| PatagoniaMet: A multi-source hydrometeorological dataset for Western Patagonia | Scientific Data | Aguayo, R.; León-Muñoz, J.; Aguayo, M.; Baez-Villanueva, O.; Zambrano-Bigiarini, M.; Fernández, A.; Jacques-Coper, M. | 2024 | Agua y Extremos; Zonas Costeras | 10.1038/s41597-023-02828-2 | https://doi.org/10.1038/s41597-023-02828-2 | art6 | Vol: 11 Issue: 1 | 20524463 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Western Patagonia (40–56°S) is a clear example of how the systematic lack of publicly available data and poor quality control protocols have hindered further hydrometeorological studies. To address these limitations, we present PatagoniaMet (PMET), a compilation of ground-based hydrometeorological data (PMET-obs; 1950–2020), and a daily gridded product of precipitation and temperature (PMET-sim; 1980–2020). PMET-obs was developed considering a 4-step quality control process applied to 523 hydrometeorological time series obtained from eight institutions in Chile and Argentina. Following current guidelines for hydrological datasets, several climatic and geographic attributes were derived for each catchment. PMET-sim was developed using statistical bias correction procedures, spatial regression models and hydrological methods, and was compared against other bias-corrected alternatives using hydrological modelling. PMET-sim was able to achieve Kling-Gupta efficiencies greater than 0.7 in 72% of the catchments, while other alternatives exceeded this threshold in only 50% of the catchments. PatagoniaMet represents an important milestone in the availability of hydro-meteorological data that will facilitate new studies in one of the largest freshwater ecosystems in the world. © 2024, The Author(s). |
| Public Perception of Drought and Extreme Rainfall Impacts in a Changing Climate: Aconcagua Valley and Chañaral, Chile | Sustainability (Switzerland) | Aldunce, P.; Haverbeck, F.; Sapiains, R.; Quilaqueo, A.; Castro, C. | 2024 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.3390/su16187916 | https://doi.org/10.3390/su16187916 | art7916 | Vol: 16.0 Issue: 18.0 | 20711050 | Thomson Reuters ISI (SCIE; SSCI) | All Open Access; Gold Open Access | English | Droughts and extreme rainfall events are two of the hazards that affect many people in the world and are frequent and complex hazards, the rate of occurrence and magnitude of which are expected to increase in a changing climate. In this context, understanding how different actors perceive changes in climate, drought, and extreme rainfall events and their impacts is relevant in contributing to successfully implementing adaptation strategies to reduce their impacts. This research seeks to explore the main changes the climate has undergone and the impacts of drought and precipitation events, as perceived at local levels by different stakeholders. A multi-method approach was applied, including qualitative methods such as observation, 51 semi-structured interviews, and document reviews in Chañaral and the Aconcagua Valley, Chile. This research shows what the perceived changes in climate are and that drought and extreme rainfall events have affected the well-being of the local people by severely impacting the economy, the environment, social interactions, quality of life, and human health. Additionally, the perception of climate change and its impacts vary depending on the type of hazard and the social, geographical, and environmental contexts in which communities live. This study is useful as it has generated knowledge relevant to inform policy decisions, practice, and theory. © 2024 by the authors. |
| HESS Opinions: The unsustainable use of groundwater conceals a "Day Zero" | Hydrology and Earth System Sciences | Alvarez-Garreton, C.; Boisier, J.; Garreaud, R.; González, J.; Rondanelli, R.; Gayó, E.; Zambrano-Bigiarini, M. | 2024 | Agua y Extremos; Ciudades Resilientes; Zonas Costeras | 10.5194/hess-28-1605-2024 | https://doi.org/10.5194/hess-28-1605-2024 | 1605-1616 | Vol: 28.0 Issue: 7.0 | 10275606 | Thomson Reuters ISI (SCIE) | | English | Water scarcity is a pressing global issue driven by increasing water demands and changing climate conditions. Based on novel estimates of water availability and water use in Chile, we examine the challenges and risks associated with groundwater (GW) withdrawals in the country's central-north region (27-35°ĝ€¯S), where extreme water stress conditions prevail. As total water use within a basin approaches the renewable freshwater resources, the dependence on GW reserves intensifies in unsustainable ways. This overuse has consequences that extend beyond mere resource depletion, manifesting into environmental degradation, societal conflict, and economic costs. We argue that the "Day Zero"scenario, often concealed by the uncertain attributes of GW resources, calls for a reconsideration of water allocation rules and a broader recognition of the long-term implications of unsustainable GW use. Our results offer insights for regions worldwide facing similar water scarcity challenges and emphasize the importance of proactive and sustainable water management strategies. © 2024 Camila Alvarez-Garreton et al. |
| On the timescale of drought indices for monitoring streamflow drought considering catchment hydrological regimes | Hydrology and Earth System Sciences | Baez-Villanueva, O.; Zambrano-Bigiarini, M.; Miralles, D.; Beck, H.; Siegmund, J.; Alvarez-Garreton, C.; Verbist, K.; Garreaud, R.; Boisier, J.; Galleguillos, M. | 2024 | Agua y Extremos; Cambio de Uso de Suelo | 10.5194/hess-28-1415-2024 | https://doi.org/10.5194/hess-28-1415-2024 | 1415-1439 | Vol: 28.0 Issue: 6.0 | 10275606 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | There is a wide variety of drought indices, yet a consensus on suitable indices and temporal scales for monitoring streamflow drought remains elusive across diverse hydrological settings. Considering the growing interest in spatially distributed indices for ungauged areas, this study addresses the following questions: (i) What temporal scales of precipitation-based indices are most suitable to assess streamflow drought in catchments with different hydrological regimes? (ii) Do soil moisture indices outperform meteorological indices as proxies for streamflow drought? (iii) Are snow indices more effective than meteorological indices for assessing streamflow drought in snow-influenced catchments? To answer these questions, we examined 100 near-natural catchments in Chile with four hydrological regimes, using the standardised precipitation index (SPI), standardised precipitation evapotranspiration index (SPEI), empirical standardised soil moisture index (ESSMI), and standardised snow water equivalent index (SWEI), aggregated across various temporal scales. Cross-correlation and event coincidence analysis were applied between these indices and the standardised streamflow index at a temporal scale of 1 month (SSI-1), as representative of streamflow drought events. Our results underscore that there is not a single drought index and temporal scale best suited to characterise all streamflow droughts in Chile, and their suitability largely depends on catchment memory. Specifically, in snowmelt-driven catchments characterised by a slow streamflow response to precipitation, the SPI at accumulation periods of 12-24 months serves as the best proxy for characterising streamflow droughts, with median correlation and coincidence rates of approximately 0.70-0.75 and 0.58-0.75, respectively. In contrast, the SPI at a 3-month accumulation period is the best proxy over faster-response rainfall-driven catchments, with median coincidence rates of around 0.55. Despite soil moisture and snowpack being key variables that modulate the propagation of meteorological deficits into hydrological ones, meteorological indices are better proxies for streamflow drought. Finally, to exclude the influence of non-drought periods, we recommend using the event coincidence analysis, a method that helps assessing the suitability of meteorological, soil moisture, and/or snow drought indices as proxies for streamflow drought events. © 2024 The Author(s). |
| Tornadoes and Waterspouts in Chile [Tornados y Trombas en Chile] | | Bastías-Curivil, C.; Rondanelli, R.; Vicencio, J.; Matus, F.; Caballero, V.; Munoz, F.; Barraza, J.; Campos, D.; Valenzuela, R.; de la Maza, A. | 2024 | Agua y Extremos; Zonas Costeras | 10.6084/M9.FIGSHARE.25119566.V3 | https://figshare.com/articles/dataset/Tornadoes_and_Waterspouts_in_Chile_Tornados_y_Trombas_en_Chile/25119566/3 | | | | Figshare | Creative Commons Attribution 4.0 International | English | We provide a dataset of tornadoes and waterspouts in Chile from 1554 to present based in chronicles, newspaper articles, social media, scientific literature and books. The database includes only those events that have been qualified as more than likely a tornado or waterspout based on a subjective qualification by the researchers. For each tornado we provide at least one geographical location point, the local and UTC hour (if known) and for most cases an estimation of the intensity based on the Enhanced Fujita damage scale.The following are the parameters contained in the database:
N°: This is the entry number or identifier for each record in the file.Location: The name of the place where the weather event occurred.Latitude: The geographical latitude coordinate of the event's location.Longitude: The geographical longitude coordinate of the event's location.Date (Gregorian Calendar): The date when the event occurred, according to the Gregorian calendar.Hour (local): The local time when the event occurred.Hour (UTC): The time of the event in Coordinated Universal Time (UTC).Sound: A binary indicator (usually 1 for 'Yes' and 0 for 'No') showing whether there was a notable sound associated with the event.Hail: A binary indicator showing whether hail was a feature of the weather event.Electric Storm: A binary indicator showing whether the event involved an electric storm.Damage: A binary indicator showing whether there was any damage resulting from the event.Tornado: A binary indicator showing whether a tornado was a part of the event.Waterspout: A binary indicator showing whether a waterspout was observed during the event.Register: This column refers to the existence of some witness account or visual material of a rotating column.Max. EF Rating: The maximum Enhanced Fujita Scale rating assigned to the tornado, indicating its intensity.Analyst: The name or initials of the person who analyzed or reported the event.Fatalities: The number of fatalities (deaths) caused by the event.Injured: The number of injuries reported due to the event.Link to Documents: References or links to documents where the event is described or recorded.Sources: The sources or references from where the information about the event is derived.Comments: Additional remarks or notes about the event, providing context or extra details.
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| A pioneering approach to measure increased resilience to face climate change: insights from the Race to Resilience campaign | Environmental Research Communications | Billi, M.; Bórquez, R.; Varela, J.; Aldunce, P.; Aspee, N.; Beauchamp, E.; Berríos, P.; Cuevas, M.; Loboguerrero, A.; Mason Bustos, F.; Patwardhan, A.; Rojas, M. | 2024 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política | 10.1088/2515-7620/ad6d37 | https://doi.org/10.1088/2515-7620/ad6d37 | art095006 | Vol: 6.0 Issue: 9.0 | 25157620 | Thomson Reuters ISI (SCIE) | | English | This paper illustrates a methodology to measure the impact of resilience-building actions on the increased resilience of people and natural systems to face climate change, developed and field-tested around the Race to Resilience Campaign. Despite increasing acknowledgment of the need for robust methodologies and indicators to monitor and evaluate efforts across adaptation planning and implementation, and provide credibility, accountability and transparency to such actions, there is still a lack of sufficiently standardized and agreed upon metrics able to capture the effect of resilience-building actions. The proposal illustrated in this manuscript offers a pioneering approach for high-level tracking, monitoring and evaluation of resilience-building efforts of non-state actors, based on two complementing sets of metrics: depth metrics measure the degree to which an action is generating a change to fundamental conditions which can demonstrably be related to increasing resilience; while magnitude metrics offer a quantification of the beneficiaries that are affected by these changes. Underlying both stand the Resilience Attributes: properties which can be soundly associated with triggering resilience across different systems, and which can then be used to assess increased resilience ‘by proxy’: that is, by seeing how an action sets forth changes in properties commonly associated with resilience. These Attributes were identified based on updated scientific literature and co-construction exercises with global experts. The integration of Depth and Magnitude indices, adjusted by a Confidence Index evaluating data reliability, allows to estimate the overall contribution of a set of actions on increasing resilience against climate challenges. Based on the above, a possible Monitoring & Evaluation cycle is proposed, and an illustration is offered on two case studies from the Race to Resilience campaign. Key strengths, lessons learned and insights are summarized to stimulate the global discussion, in the context of the Global Stocktake and Global Goal on Adaptation. © 2024 The Author(s). Published by IOP Publishing Ltd. |
| CR2LUC: Historical (1950-2020) land use and land cover in continental Chile | | Boisier, J.; Marinao, R. | 2024 | Agua y Extremos | 10.5281/ZENODO.13324250 | https://zenodo.org/doi/10.5281/zenodo.13324250 | | | | Zenodo | Creative Commons Attribution 4.0 International | | The CR2LUC product was created to track long-term land-use changes in Chile since 1950, using a method that combines historical data with satellite information. Unlike recent land use/cover estimates that rely heavily on satellite data, CR2LUC integrates various sources, including agricultural censuses and other national statistics. This reconstruction involves extensive data preprocessing, such as digitizing historical documents. Key data sources include Agricultural Censuses (1955, 1965, 1976, 1997, 2007), annual crop statistics (1997-2021), and cadastres for fruits, viticulture, and vegetation.
This dataset has been developed within the framework of the Center for Climate and Resilience Research (CR2, ANID/FONDAP/1523A0002) and the research project ANID/FSEQ210001. |
| CR2WU: Water use dataset for the period 1950-2020 in continental Chile. | | Boisier, J.; Marinao, R.; Alvarez Garreton, C. | 2024 | Agua y Extremos | 10.5281/ZENODO.13324235 | https://zenodo.org/doi/10.5281/zenodo.13324235 | | | | Zenodo | Creative Commons Attribution 4.0 International | | The CR2WU dataset includes consumptive and non-consumptive water uses as volumetric fluxes from various sectors at the commune level (the smallest administrative unit in Chile), with annual resolution from 1950 to 2020. The computation involves two distinct methodologies: one for sectors encompassing land use, land-use change, and forestry (LULUCF) and another for other water-consuming sectors.
This dataset been developed within the framework of the Center for Climate and Resilience Research (CR2, ANID/FONDAP/1523A0002) and the research project ANID/FSEQ210001. |
| Infrastructure Conditions and Service Quality in Rural Drinking Water Systems: A Cluster Analysis of Community-Based Organizations in Chile | Journal of Water Resources Planning and Management | Bopp, C.; Nicolas-Artero, C.; Blanco, E.; Fuster, R. | 2024 | Agua y Extremos | 10.1061/JWRMD5.WRENG-6318 | https://doi.org/10.1061/JWRMD5.WRENG-6318 | art05024003 | Vol: 150.0 Issue: 6.0 | 07339496 | Thomson Reuters ISI (SCIE) | | English | In many countries, the drinking water provision in rural areas is in the charge of the users themselves, who constitute rural water supply services (RWS) to operate and maintain the public infrastructure provided by the State. However, in practice, the condition of the components of the implied infrastructure managed by RWS varies considerably, which has important implications for delivering high-quality service. This case study explores the nexus among infrastructure conditions, performance outcomes, and organization characteristics using the case of Chile. Using representatives' assessments from 406 RWS regarding the need for the replacement of several components of their system's infrastructure, an index of infrastructure conditions was constructed and subjected to a cluster analysis that identified three dissimilar groups of RWS. The top condition cluster represents a reference group (benchmark) that exhibits the highest scores in water quality, quantity, and delivery reliability, which highlights the association between infrastructure conditions and performance outcomes. In addition, a comparison of RWS attributes of these three clusters allowed us to characterize them in terms of structural, organizational, management, and environmental variables. This study sheds light on the role of RWS infrastructure in enabling these organizations to deliver high-quality service, and the findings serve to guide policy actions and tailored planning. The methodology presented here can be applied in other regions beyond that of the case study because it represents a low-cost tool to measure the infrastructure condition of RWS based on representatives' assessments and is an effective and practical way to distinguish RWS most in need of support. © 2024 American Society of Civil Engineers. |
| Vegetation and environmental responses from extreme glacial to extreme interglacial conditions in central Isla Grande de Chiloé (∼42°S), northwestern Patagonia | Quaternary Science Reviews | Briones, D.; Guerra, L.; Soteres, R.; Moreno, P. | 2024 | Agua y Extremos | 10.1016/j.quascirev.2024.108927 | https://doi.org/10.1016/j.quascirev.2024.108927 | art108927 | Vol: 344.0 | 02773791 | Thomson Reuters ISI (SCIE) | | English | We examine the vegetation and environmental evolution of central Isla Grande de Chiloé (IGC), northwestern Patagonia (NWP), spanning the two climatic endmembers of the last glacial-interglacial cycle: the Last Glacial Maximum (LGM) and the Early Holocene (EH). Our results from Lago Auquilda show Evergreen Subantarctic forests interspersed with Magellanic Moorland during the early LGM (∼30.9-26.1 ka), followed by species-poor closed-canopy Nothofagus forests with low conifer abundance and absence of Magellanic Moorland during the late LGM (∼18.9-17.9 ka). Initial canopy fragmentation at ∼17.9 ka gave way to rapid densification and diversification of trees, herbs, and vines characteristic of North Patagonian rainforests (NPRF), marking the onset of the Last Glacial Termination (T1). Closed-canopy NPRF established between ∼15.5-14.8 ka, followed by mixed forests with shade- and cold-tolerant hygrophilous NPRF conifers until abrupt increases in shade-intolerant trees favored by local fires between ∼12.6-11.4 ka. NPRF conifers disappeared as thermophilous species of the Valdivian rainforest and fire activity increased between ∼11.4-8.7 ka. We interpret that temperate rainforest inhabited the periphery of the Patagonian Ice Sheet in NWP under cold and hyperhumid conditions during the LGM. Precipitation was highest in the early LGM, declined during the late LGM, diminished to an early T1 minimum between ∼17.1-16.4 ka, and then increased steadily to a maximum between ∼14.8-12.6 ka, overlapping with the Antarctic Cold Reversal (ACR). Subsequent declines at ∼12.6 ka and ∼11.4 ka led to extreme warm-dry conditions during the EH with intense fire activity. Hyperhumid conditions during the LGM and ACR imply equatorward-shifted Southern Westerly Winds (SWW), minimum precipitation during the early portion of T1 relates to poleward-shifted SWW, and the EH warm-dry phase reflects a zonally symmetric decline in SWW intensity. Our Lago Auquilda record replicates the timing and structure of changes revealed by multiple paleoclimate studies throughout western Patagonia which, in turn, are synchronous/coherent with key southern mid- and high-latitude records. © 2024 Elsevier Ltd |
| The key role of extreme weather and climate change in the occurrence of exceptional fire seasons in south-central Chile | Weather and Climate Extremes | Carrasco-Escaff, T.; Garreaud, R.; Bozkurt, D.; Jacques-Coper, M.; Pauchard, A. | 2024 | Agua y Extremos; Zonas Costeras | 10.1016/j.wace.2024.100716 | https://doi.org/10.1016/j.wace.2024.100716 | art100716 | Vol: 45.0 | 22120947 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Unprecedentedly large areas were burned during the 2016/17 and 2022/23 fire seasons in south-central Chile (34-39°S). These seasonal-aggregated values were mostly accounted for human-caused wildfires within a limited period in late January 2017 and early February 2023. In this paper, we provide a comprehensive analysis of the meteorological conditions during these events, from local to hemispheric scales, and formally assess the contribution of climate change to their occurrence. To achieve this, we gathered monthly fire data from the Chilean Forestry Corporation and daily burned area estimates from satellite sources. In-situ and gridded data provided near-surface atmospheric insights, ERA5 reanalysis helped analyze broader wildfire features, high-resolution simulations were used to obtain details of the wind field, and large-ensemble simulations allowed the assessment of climate change's impact on extreme temperatures during the fires. This study found extraordinary daily burned area values (>65,000 ha) occurring under extreme surface weather conditions (temperature, humidity, and winds), fostered by strong mid-level subsidence ahead of a ridge and downslope winds converging towards a coastal low. Daytime temperatures and the water vapor deficit reached the maximum values observed across the region, well above the previous historical records. We hypothesize that these conditions were crucial in exacerbating the spread of fire, along with longer-term atmospheric processes and other non-climatic factors such as fuel availability and increasing human-driven ignitions. Our findings further reveal that climate change has increased the probability and intensity of extremely warm temperatures in south-central Chile, underscoring anthropogenic forcing as a significant driver of the extreme fire activity in the region. © 2024 The Authors |
| Engaging diverse knowledge holders in adaptation research | Nature Climate Change | Cundill, G.; Harvey, B.; Ley, D.; Singh, C.; Huson, B.; Aldunce, P.; Biesbroek, R.; Lawrence, J.; Morchain, D.; Nalau, J.; Simpson, N.; Totin, E. | 2024 | Agua y Extremos | 10.1038/s41558-024-02056-5 | https://doi.org/10.1038/s41558-024-02056-5 | 662-664 | Vol: 14.0 Issue: 7.0 | 1758678X | Thomson Reuters ISI (SCIE; SSCI) | | en | Adaptation evidence and knowledge are
diverse and unequally represented in global
adaptation discourse. The Adaptation Futures
2023 conference sought to bring this diversity
together to advance more inclusive and
impactful adaptation science, and confronted
both the benefits and the trade-offs that this
effort entails. |
| Land Management Drifted: Land Use Scenario Modeling of Trancura River Basin, Araucanía, Chile | Land | Díaz-Jara, A.; Manuschevich, D.; Grau, A.; Zambrano-Bigiarini, M. | 2024 | Agua y Extremos | 10.3390/land13020157 | https://www.mdpi.com/2073-445X/13/2/157 | 157 | Vol: 13.0 Issue: 2.0 | 2073-445X | Thomson Reuters ISI (SSCI) | All Open Access; Gold Open Access | English | Modeling land use scenarios is critical to understand the socio-environmental impacts of current decisions and to explore future configurations for management. The management of regulations and permits by central and local governments plays an important role in shaping land use, with different complexities arising from site-specific socioeconomic dynamics. In Chile, the complexity is even more evident due to insufficient binding land regulations, fragmented government procedures, and the primacy of cities over rural areas. Yet land use must be managed to support sustainable development. This research integrates several state management dynamics into scenario modeling to support decision making at the basin scale through 2050. We employed a mixed qualitative-quantitative approach using interviews with state officials and local stakeholders as the basis for the Conversion of Land Use and its Effects (CLUE) model, which resulted in three scenarios with spatially explicit maps. Key findings indicate that opportunities for developing normative planning tools are limited, leaving state management without clear direction. However, current management practices can address problematic activities such as second-home projects and industrial monocultures while promoting small-scale agriculture. Scenario modeling is useful for understanding how the specifics that arise from the scalar dynamics of state management affect land use change and how existing management resources can be leveraged to achieve positive outcomes for both the ecosystem and society. |
| Multisequal aeolian deposition during the Holocene in southwestern Patagonia (51°S) was modulated by southern westerly wind intensity and vegetation type | Quaternary Science Reviews | Flores-Aqueveque, V.; Villaseñor, T.; Gómez-Fontealba, C.; Alloway, B.; Alfaro, S.; Pizarro, H.; Guerra, L.; Moreno, P. | 2024 | Agua y Extremos | 10.1016/j.quascirev.2024.108616 | https://doi.org/10.1016/j.quascirev.2024.108616 | art108616 | Vol: 331.0 | 02773791 | Thomson Reuters ISI (SCIE) | | English | We studied a multisequal soil succession (MSS) just south of Torres del Paine National Park (51°S), at the present-day core of the Southern Westerly Winds (SWW). The Río Serrano Section comprises paleosol horizons with associated intervening loess and sandy loess beds formed during the Holocene. Our record suggests strong and stable aeolian activity between ∼9.3–7.2 ka followed by a decline with centennial-scale variations until ∼5 ka. A strengthening commenced at ∼5 ka and culminated in a maximum between ∼2.2–0.5 ka with millennial-scale variations. Subsequent weakening of aeolian activity between ∼0.5 and 0 ka was coeval with the deposition of a ∼40 cm-thick paleosol, after which aeolian activity increased abruptly and reached an unprecedented maximum starting in the mid-20th century. The inferred wind intensity variations from our data bear partial agreement with competing hypotheses of SWW evolution, which postulate minimum SWW influence in SW Patagonia during the early Holocene and maximum influence during the Late Holocene, or vice versa. When analyzed through the lens of vegetation physiognomy/distribution and associated hydrological balance inferences from neighboring sites, our results suggest a primary control by precipitation and wind speeds associated to SWW strength at regional scale, modulated by the position of the forest/steppe ecotone east of the austral Andes. Human activities during the mid-20th century (deforestation, fire-regime shifts, livestock grazing, land use changes) caused an unprecedented increase in aeolian activity through decreased vegetation cover that increased sediment availability for aeolian transport, marking a striking difference with the magnitude of natural processes before the Anthropocene. Our results highlight the importance of climate change and natural/human-driven changes in vegetation cover for deciphering wind intensity histories, particularly in the transition from humid to semiarid environments along the eastern slope of the southern Patagonian Andes. © 2024 Elsevier Ltd |
| Atmospheric Rivers in South-Central Chile: Zonal and Tilted Events | Atmosphere | Garreaud, R.; Jacques-Coper, M.; Marín, J.; Narváez, D. | 2024 | Agua y Extremos; Zonas Costeras | 10.3390/atmos15040406 | https://doi.org/10.3390/atmos15040406 | art406 | Vol: 15.0 Issue: 4.0 | 20734433 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The extratropical west coast of South America has one of the largest frequencies of landfalling atmospheric rivers (ARs), with dozens of events per season that account for ~50% of the annual precipitation and can produce extreme rainfall events in south-central Chile. Most ARs form an acute angle with the Andes, but, in some cases, the moist stream impinges nearly perpendicular to the mountains, referred to as zonal atmospheric rivers (ZARs). Enhanced surface-based and upper-air measurements in Concepcion (36.8° S), as well as numerical simulations, were used to characterize a ZAR and a meridionally oriented AR in July 2022. They represent extremes of the broad distribution of winter storms in this region and exhibit key features that were found in a composite analysis based on larger samples of ZARs and tilted ARs. The latter is associated with an upper-level trough, broad-scale ascent, extratropical cyclone, and cold front reaching southern Chile. Instead, ZARs are associated with tropospheric-deep, strong zonal flow and a stationary front across the South Pacific, with ascent restricted upstream of the Andes. Consequently, ZARs have minimum precipitation offshore but a marked orographic precipitation enhancement and exhibit relatively warm temperatures, thus resulting in an augmented risk of hydrometeorological extreme events. © 2024 by the authors. |
| Chile’s Valparaíso hills on fire | Science | González, M.; Syphard, A.; Fischer, A.; Muñoz, A.; Miranda, A. | 2024 | Agua y Extremos; Cambio de Uso de Suelo | 10.1126/science.ado5411 | https://doi.org/10.1126/science.ado5411 | 1424 | Vol: 383.0 Issue: 6690.0 | 00368075 | Thomson Reuters ISI (SCIE) | | English | [No abstract available] |
| Recent multispecies tree-growth decline reveals a severe aridity change in Mediterranean Chile | Environmental Research Letters | González-Reyes, Á.; Christie, D.; Schneider-Valenzuela, I.; Venegas-González, A.; Muñoz, A.; Hadad, M.; Gipoulou-Zuñiga, T.; Tapia-Marzan, V.; Gibson-Carpintero, S.; Santini-Junior, L.; LeQuesne, C.; Villalba, R. | 2024 | Agua y Extremos | 10.1088/1748-9326/ad4049 | https://doi.org/10.1088/1748-9326/ad4049 | art064046 | Vol: 19.0 Issue: 6.0 | 17489326 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Soil moisture (SM) is a crucial factor in the water cycle, sustaining ecosystems and influencing local climate patterns by regulating the energy balance between the soil and atmosphere. Due to the absence of long-term, in-situ measurements of SM, studies utilizing satellite-based data and tree-ring analysis have become valuable in assessing variations of SM at regional and multi-century scales, as well as determining its effects on tree growth. This information is particularly pertinent in biodiversity hotspots made up of semi-arid ecosystems currently threatened by climate change. In the Mediterranean Chile region (MC; 30°-37° S), an ongoing megadrought since 2010 has resulted in a significant decline in the forest throughout the area. However, the impact of SM on tree growth at a multi-species and regional level remains unexplored. We analyzed a new network of 22 tree-ring width chronologies across the MC to evaluate the main spatiotemporal tree-growth patterns of nine woody species and their correlation with SM, using PCA. We also reconstructed the SM variations over the past four centuries and assessed its connection with large-scale climate forcings. Our results indicate that the primary growth patterns (PC1) explained 27% of the total variance and displayed a significant relationship with SM between 1982-2015 (r = 0.91), accurately reflecting the current megadrought. The tree-ring SM reconstruction covers the period 1616-2018 and shows a strong decrease around the year 2007, revealing an unprecedented recent change in aridity with respect to the last four centuries. The intensity of the South Pacific subtropical anticyclone, which primarily owe their existence to the subsiding branch of the Hadley Cell, appears as the primary climatic mechanism correlated with the reconstruction and the present aridity conditions in MC. The current SM conditions align with anticipated aridity changes in MC, providing a bleak perspective of future regional climate. © 2024 The Author(s). Published by IOP Publishing Ltd. |
| Orbital modulation of subtropical versus subantarctic moisture sources in the southeast Pacific mid-latitudes | Nature Communications | Kaiser, J.; Schefuß, E.; Collins, J.; Garreaud, R.; Stuut, J.; Ruggieri, N.; De Pol-Holz, R.; Lamy, F. | 2024 | Agua y Extremos | 10.1038/s41467-024-51985-4 | https://doi.org/10.1038/s41467-024-51985-4 | art7512 | Vol: 15.0 Issue: 1.0 | 20411723 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Reconstructing rainfall variability and moisture sources is a critical aspect to understand past and future hydroclimate dynamics. Here, we use changes in the deuterium content of land-plant leaf waxes from two marine sediment cores located off Chile to reconstruct changes in rainfall amount and variation in moisture sources over the last ~50 ka. The records indicate increased moisture in central Chile during precession maxima, but an obliquity modulation is evident in southern Chile. While the southern westerly winds are the dominant factor of precipitation in southern Chile by bringing moisture and perturbations from the extratropics, the subtropics represent an additional moisture source during precession maxima due to a stronger subtropical jet increasing moisture transport from the tropics to the mid-latitudes. These findings imply that a combination of orbital modulation of moisture sources and rainfall amount explains the last glacial moisture maximum and early Holocene moisture minimum in south-central Chile. © The Author(s) 2024. |
| Why the timing of climate assessments matters | Nature | Lambert, F. | 2024 | Agua y Extremos | 10.1038/d41586-024-03156-0 | https://doi.org/10.1038/d41586-024-03156-0 | 9-9 | Vol: 634.0 Issue: 8032.0 | 00280836 | Thomson Reuters ISI (SCIE) | | en | The Intergovernmental Panel on Climate Change and the Paris agreement must align their schedules — or progress will slip. © Springer Nature Limited 2024. |
| Characterizing the Atmospheric Mn Cycle and Its Impact on Terrestrial Biogeochemistry | Global Biogeochemical Cycles | Lu, L.; Li, L.; Rathod, S.; Hess, P.; Martínez, C.; Fernandez, N.; Goodale, C.; Thies, J.; Wong, M.; Alaimo, M.; Artaxo, P.; Barraza, F.; Barreto, A.; Beddows, D.; Chellam, S.; Chen, Y.; Chuang, P.; Cohen, D.; Dongarrà, G.; Gaston, C.; Gómez, D.; Morera-Gómez, Y.; Hakola, H.; Hand, J.; Harrison, R.;... | 2024 | Agua y Extremos | 10.1029/2023GB007967 | https://doi.org/10.1029/2023GB007967 | arte2023GB007967 | Vol: 38.0 Issue: 4.0 | 08866236 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | The role of manganese (Mn) in ecosystem carbon (C) biogeochemical cycling is gaining increasing attention. While soil Mn is mainly derived from bedrock, atmospheric deposition could be a major source of Mn to surface soils, with implications for soil C cycling. However, quantification of the atmospheric Mn cycle, which comprises emissions from natural (desert dust, sea salts, volcanoes, primary biogenic particles, and wildfires) and anthropogenic sources (e.g., industrialization and land-use change due to agriculture), transport, and deposition, remains uncertain. Here, we use compiled emission data sets for each identified source to model and quantify the atmospheric Mn cycle by combining an atmospheric model and in situ atmospheric concentration measurements. We estimated global emissions of atmospheric Mn in aerosols (<10 μm in aerodynamic diameter) to be 1,400 Gg Mn year−1. Approximately 31% of the emissions come from anthropogenic sources. Deposition of the anthropogenic Mn shortened Mn “pseudo” turnover times in 1-m-thick surface soils (ranging from 1,000 to over 10,000,000 years) by 1–2 orders of magnitude in industrialized regions. Such anthropogenic Mn inputs boosted the Mn-to-N ratio of the atmospheric deposition in non-desert dominated regions (between 5 × 10−5 and 0.02) across industrialized areas, but that was still lower than soil Mn-to-N ratio by 1–3 orders of magnitude. Correlation analysis revealed a negative relationship between Mn deposition and topsoil C density across temperate and (sub)tropical forests, consisting with atmospheric Mn deposition enhancing carbon respiration as seen in in situ biogeochemical studies. © 2024. The Authors. |
| Extreme coastal El Niño events are tightly linked to the development of the Pacific Meridional Modes | npj Climate and Atmospheric Science | Martinez-Villalobos, C.; Dewitte, B.; Garreaud, R.; Loyola, L. | 2024 | Agua y Extremos | 10.1038/s41612-024-00675-5 | https://doi.org/10.1038/s41612-024-00675-5 | art123 | Vol: 7.0 Issue: 1.0 | 23973722 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Coastal El Niño events—marine heatwaves instances in the far eastern Tropical Pacific during otherwise basin-scale neutral or cold conditions—can have severe societal impacts for countries along the west coast of South America, as exemplified by the 2017 and 2023 Peru-Ecuador floods. Due to the brevity of the observational record, it is not well understood whether these events are driven by local or large-scale processes. Here, to overcome this limitation we use a data-driven modeling approach to address their return period and forcing mechanisms. It is shown that extreme coastal El Niño events are a local manifestation in the eastern tropical Pacific of the constructive interactions of the Pacific Meridional Modes (PMM). Specifically, the North PMM yields a dipole-like anomaly SST pattern along the equator that favors its development, while the positive phase of the South PMM reinforces it. A smaller group of more moderate coastal events are remotely driven by zonal wind anomalies in the western tropical Pacific without the PMMs’ influence. The role of PMMs in the development of extreme coastal El Niño suggests that they may be more predictable than previously thought. © The Author(s) 2024. |
| Comparing SPI and SPEI to detect different precipitation and temperature regimes in Chile throughout the last four decades | Atmospheric Research | Meseguer-Ruiz, O.; Serrano-Notivoli, R.; Aránguiz-Acuña, A.; Fuentealba, M.; Nuñez-Hidalgo, I.; Sarricolea, P.; Garreaud, R. | 2024 | Agua y Extremos; Ciudades Resilientes | 10.1016/j.atmosres.2023.107085 | https://doi.org/10.1016/j.atmosres.2023.107085 | art107085 | Vol: 297 | 01698095 | Thomson Reuters ISI (SCIE) | | English | Droughts are one of the main environmental challenges facing the world this century. The latitudinal and orographic characteristics of continental Chile leads different areas within it to experience very different regimes of precipitation and temperature, resulting in a wide variation in the occurrence and severity of droughts. Using the CR2Met 5 × 5 km resolution gridded monthly dataset covering the years from 1979 to 2019, we calculated the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evaporation Index (SPEI) of March and September at 3-, 6-, 9-, 12- and 24-months to: 1) relate them with different climate modes, and 2) determine their temporal evolution. We found that the Pacific Decadal Oscillation shows low positive correlations with SPI but no significant correlations with SPEI. The Multivariate El Niño Southern Oscillation shows different correlations in northern Chile, as well as El Niño 1 + 2 and the Antarctic Oscillation, for both SPI and SPEI. Both SPI and SPEI show negative (drier) trends in the north and center of Chile, while positive (wetter) trends appear in the south. SPEI shows stronger and more significant negative trends, influenced by the overall warming of the country. Warming trends are lower on the coast, so SPI could be a good indicator for coastal areas, while SPEI could be a good indicator for inland areas. Climate modes are useful for monthly and annual predictions, and by being a good drought predictor, they can help inform key public policies. These results are expected to help Chilean decision makers dealing with the challenges facing water management in the immediate future. © 2023 Elsevier B.V. |
| Development of a temperate rainforest zonation on the Pacific slopes of the North Patagonian Andes since ∼18 ka | Quaternary Science Reviews | Moreno, P.; Alloway, B.; Valenzuela, M.; Villacís, L.; Villa-Martínez, R. | 2024 | Agua y Extremos | 10.1016/j.quascirev.2024.108630 | https://doi.org/10.1016/j.quascirev.2024.108630 | art108630 | Vol: 332.0 | 02773791 | Thomson Reuters ISI (SCIE) | | English | Few studies along the western slopes of the Andes in Northwestern Patagonia (NWP: 40°-44°S) allow examining vegetation development through environmental gradients in latitude and elevation along a time continuum since the Last Glacial Termination (T1, ∼18-11 ka). This complete biostratigraphic context is necessary for assessing the sequence, timing, rates, and direction of compositional/structural changes of the former vegetation, and for deciphering their environmental drivers. Here we report palynological results from two NWP sites spaced ∼22 km apart on the western Andean slopes, Caleta Puelche roadside section located near sea level and Lago Reflejos at mid elevations (∼800 m a.s.l.) and assess their continuous records since local ice-free conditions against other NWP sites. We find that cold-tolerant early successional trees dominated the initial stages of vegetation development in the Seno Reloncaví lowlands (∼18-17 ka), followed by thermophilous shade-tolerant North Patagonian rainforest (NPRF) trees, which achieved their maxima between ∼17 and 15 ka at low-elevations. A spread of cold- and shade-tolerant hygrophilous NPRF conifers ensued (∼14.8-13 ka) reaching similar magnitude at low- and mid-elevations, interrupted by increases in trees favored by canopy fragmentation linked to fire and explosive volcanism (∼13-11 ka). Thermophilous, shade-intolerant, summer-drought tolerant Valdivian rainforest (VRF) trees increased and achieved maxima between ∼10 and 8 ka, most notably in the lowlands, coeval with peak abundance of the NPRF conifers Fitzroya/Pilgerodendron and Podocarpus nubigena in mid-elevation Lago Reflejos, contemporaneous with their virtual disappearance near sea level. Widespread increases in cold-tolerant hygrophilous NPRF trees occurred after ∼8 ka, followed by mixing of NPRF and VRF elements in the lowlands after ∼6.3 ka with centennial-scale alternations. Inter-site and regional coherences of our findings suggest that variations in Southern Westerly Wind influence, along with disturbance regimes of natural and human origin, have driven the composition, structure, dynamics, and zonation of temperate rainforests in NWP since T1. We observe that Lago Reflejos features the highest abundance of Fitzroya cupressoides at regional scale since ∼12 ka, attesting to the importance of mid-elevation Andean environments for the persistence of these highly valued trees in the context of postglacial climate evolution, shifts in fire regimes, volcanic, and human disturbance in NWP. © 2024 Elsevier Ltd |
| Climatic and disturbance impacts on temperate rainforest development since ∼18 ka in central-west Isla Grande de Chiloé (42.7°S) | Quaternary Science Reviews | Moreno, P.; Gonzalorena, L.; Hernández, L. | 2024 | Agua y Extremos | 10.1016/j.quascirev.2024.108688 | https://doi.org/10.1016/j.quascirev.2024.108688 | art108688 | Vol: 333.0 | 02773791 | Thomson Reuters ISI (SCIE) | | English | Understanding the role of disturbance regimes on terrestrial ecosystems is often compounded by the paucity of time series sufficiently long and detailed to capture triggering events and the sequence of changes in species composition, community structure and dynamics along a time continuum until the present. Adding complexity to this problem, disturbance regimes and the distribution/competitive interactions of participating species may vary in time with shifts in mean climatic conditions and variability. Here we present results from sediment cores we collected from small closed-basin lakes near the Pacific coast of central Isla Grande de Chiloé, a sector with the lowest seasonality and recurrence of explosive volcanic events in Northwestern Patagonia (NWP). Our aim is examining vegetation development since the last glaciation and exploring potential climatic and disturbance impacts. We found rapid establishment of closed-canopy rainforests, which have persisted with little variation in terms of physiognomy until the present. Significant changes in species composition, structure, dynamics, and rates of change are evident over the last ∼18,000 years, along with fire maxima at ∼16.7 ka, ∼12.7 ka, between ∼11.7-9 ka, from ∼2 ka to the present, and minima in the interim. Fires precede major increases in disturbance favored taxa, which correspond in timing with fire activity maxima at NWP scale. The most recent ∼2000 years coincide with the highest number and ubiquity of human occupations at central-west and NWP scale, raising the possibility that fires were driven by human activities near our study sites. We detect a conspicuous increase in disturbance-favored trees ∼150 years after deposition of the Puma Verde Tephra (∼8.3 ka) and interpret their subsequent maintenance by frequent blowdown events after ∼7.5 ka in exposed sectors of the Coastal Range. We posit that enhanced storminess driven by stronger Southern Westerly Winds since ∼7.5 ka has favored early successional opportunistic trees in detriment of old-growth forests dominated by shade-tolerant species, generating a spatial mosaic of forest patches or gaps in different stages of recovery. © 2024 |
| Unraveling the Dynamics of Moisture Transport During Atmospheric Rivers Producing Rainfall in the Southern Andes | Geophysical Research Letters | Mudiar, D.; Rondanelli, R.; Valenzuela, R.; Garreaud, R. | 2024 | Agua y Extremos; Zonas Costeras | 10.1029/2024GL108664 | https://doi.org/10.1029/2024GL108664 | arte2024GL108664 | Vol: 51.0 Issue: 13.0 | 00948276 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Atmospheric rivers (ARs) are known to produce both beneficial and extreme rainfall, leading to natural hazards in Chile. Motivated to understand moisture transport during AR events, this study performs a moisture budget analysis along 50 zonally elongated ARs reaching the western coast of South America. We identify the convergence of moist air masses of tropical/subtropical origin along the AR as the primary source of vertically integrated water vapor (IWV). Over the open ocean, moisture convergence is nearly balanced by precipitation. The advection of moisture along the AR, although smaller compared to mass convergence, significantly increases toward the landfalling region. The near conservation of IWV over the open ocean, observed by tracking a Lagrangian atmospheric column along the ARs, is the explanation behind the seemingly tropical origin of ARs in time-lapse visualizations of IWV. © 2024. The Author(s). |
| Disponibilidad y seguridad hídrica en el desarrollo de enfermedades crónicas no transmisibles ¿Nuevos factores de riesgo? | Revista Médica de Chile | Petermann-Rocha, F.; Pizarro, A.; Nazar, G.; Zambrano-Bigiarini, M.; Plaza-Garrido, A.; Díaz-Toro, F.; Troncoso-Pantoja, C.; Celis, A.; Sugg, D.; Celis-Morales, C. | 2024 | Agua y Extremos | 10.4067/s0034-98872024000500643 | https://www.revistamedicadechile.cl/index.php/rmedica/article/view/10971 | | Vol: 152.0 Issue: 5.0 | 0717-6163 | Thomson Reuters ISI (SCIE) | Derechos de autor 2024 Revista Médica de Chile | Spanish | Las enfermedades crónicas no transmisibles
(ECNT) son enfermedades de larga duración caracterizadas por presentar una lenta progresión y afectar a todos los grupos de edad y regiones en el mundo. Aunque estas patologías suelen asociarse con la edad avanzada, los datos epidemiológicos indican que tanto niños como adultos y personas mayores son vulnerables a distintos factores de riesgo que favorecen su aparición y desarrollo.
Además de los factores de riesgo clásicos (por
ejemplo, consumo de alcohol, tabaco, dieta), se
han identificado otros factores emergentes que
podrían influir directa o indirectamente en el
desarrollo de estas enfermedades. Un ejemplo
de estos últimos es el rol que podría desempeñar
la variabilidad climática, específicamente la disponibilidad de recursos hídricos, en la evolución de estas patologías. |
| A 300-year tree-ring δ18O-based precipitation reconstruction for the South American Altiplano highlights decadal hydroclimate teleconnections | Communications Earth and Environment | Rodriguez-Caton, M.; Morales, M.; Rao, M.; Nixon, T.; Vuille, M.; Rivera, J.; Oelkers, R.; Christie, D.; Varuolo-Clarke, A.; Ferrero, M.; Magney, T.; Daux, V.; Villalba, R.; Andreu-Hayles, L. | 2024 | Agua y Extremos | 10.1038/s43247-024-01385-9 | https://doi.org/10.1038/s43247-024-01385-9 | art269 | Vol: 5.0 Issue: 1.0 | 26624435 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Tropical South American climate is influenced by the South American Summer Monsoon and the El Niño Southern Oscillation. However, assessing natural hydroclimate variability in the region is hindered by the scarcity of long-term instrumental records. Here we present a tree-ring δ18O-based precipitation reconstruction for the South American Altiplano for 1700–2013 C.E., derived from Polylepis tarapacana tree rings. This record explains 56% of December–March instrumental precipitation variability in the Altiplano. The tree-ring δ18O chronology shows interannual (2–5 years) and decadal (~11 years) oscillations that are remarkably consistent with periodicities observed in Altiplano precipitation, central tropical Pacific sea surface temperatures, southern-tropical Andean ice core δ18O and tropical Pacific coral δ18O archives. These results demonstrate the value of annual-resolution tree-ring δ18O records to capture hydroclimate teleconnections and generate robust tropical climate reconstructions. This work contributes to a better understanding of global oxygen-isotope patterns, as well as atmospheric and oceanic processes across the tropics. © The Author(s) 2024. |
| Toward a South American High-Impact Weather Reports Database | Bulletin of the American Meteorological Society | Salio, P.; Bechis, H.; Ribeiro, B.; de Lima Nascimento, E.; Galligani, V.; Garcia, F.; Alvarenga, L.; de los Milagros Alvarezs Imaz, M.; Baissac, D.; Barle, M.; Bastías-Curivil, C.; Benedicto, M.; Cancelada, M.; da Costa, I.; D’Amen, D.; de Elia, R.; Diaz, D.; Páez, A.; González, S.; Goede, V.; Goñi... | 2024 | Agua y Extremos; Zonas Costeras | 10.1175/BAMS-D-23-0063.1 | https://doi.org/10.1175/BAMS-D-23-0063.1 | E1204-E1217 | Vol: 105.0 Issue: 7.0 | 00030007 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Despite southern South America being recognized as a hotspot for deep convective storms, little is known about the socioenvironmental impacts of high-impact weather (HIW) events. Although there have been past efforts to collect severe weather reports in the region, they have been highly fragmented among and within countries, sharing no common protocol, and limited to a particular phenomenon, a very specific region, or a short period of time. There is a pressing need for a more comprehensive understanding of the present risks linked to HIW events, specifically deep convective storms, on a global scale as well as their variability and potential future evolution in the context of climate change. A database of high-quality and systematic HIW reports and associated socioenvironmental impacts is essential to understand the regional atmospheric conditions leading to hazardous weather, to quantify its predictability, and to build robust early warning systems. To tackle this problem and following successful initiatives in other regions of the world, researchers, national weather service members, and weather enthusiasts from Argentina, Brazil, Chile, Paraguay, and Uruguay have embarked on a multinational collaboration to generate a standardized database of reports of HIW events principally associated with convective storms and their socioenvironmental impacts in South America. The goal of this paper is to describe this unprecedented initiative over the region, to summarize first results, and to discuss the potential applications of this collaboration. SIGNIFICANCE STATEMENT: The South American Meteorological Hazards and their Impacts Database represents a collaborative multinational initiative aimed at systematically gathering data on high-impact weather events. Cross-border information exchange and collaborative efforts between national weather services, the academic sector, users, and weather enthusiasts will improve multihazard-impact-based forecasts and risk management strategies in the region. © 2024 American Meteorological Society. |
| Climate change perceptions in Latin America: From regional consensus to sociodemographic differences | Population and Environment | Sapiains, R.; Azocar, G.; Palomo-Vélez, G.; Ugarte, A.; Aldunce, P. | 2024 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.1007/s11111-024-00464-5 | https://doi.org/10.1007/s11111-024-00464-5 | art23 | Vol: 46.0 Issue: 4.0 | 01990039 | Thomson Reuters ISI (SSCI) | | English | Despite its low contribution to greenhouse gases emission, Latin America is one of the most vulnerable regions to climate change. Economic, social, and political factors make difficult the preparation for ongoing and future impacts. Few studies have explored how people in this region perceive and respond to climate change. In this scenario, we conducted an online survey to address the following research question: How sociodemographic factors are influencing perceptions and emotional responses associated with climate change in LA countries? The final sample consisted of 7232 people, with an error of 2.8% for the total population from 18 countries, representing 67% of the region’s internet-accessible population. Data analysis involved descriptive statistics, cross-tabulations, and mixed linear models. Results indicate a consensus on the fact that climate change is already happening, that is totally or partially caused by human activities, that will worsen poverty and inequalities but also that is an opportunity to build a fairer society. Sociodemographic differences were also found, showing the importance of sex, age and having or not having children in multiple variables. We hope this study will contribute to a better understanding of this complex social issue, informing policies to encourage a greater engagement with climate action. © The Author(s), under exclusive licence to Springer Nature B.V. 2024. |
| Changes in South American surface ozone trends: exploring the influences of precursors and extreme events | Atmospheric Chemistry and Physics | Seguel, R.; Castillo, L.; Opazo, C.; Rojas, N.; Nogueira, T.; Cazorla, M.; Gavidia-Calderón, M.; Gallardo, L.; Garreaud, R.; Carrasco-Escaff, T.; Elshorbany, Y. | 2024 | Agua y Extremos; Ciudades Resilientes | 10.5194/acp-24-8225-2024 | https://doi.org/10.5194/acp-24-8225-2024 | 8225-8242 | Vol: 24.0 Issue: 14.0 | 16807316 | Thomson Reuters ISI (SCIE) | | English | In this study, trends of 21st-century ground-level ozone and ozone precursors were examined across South America, a less-studied region where trend estimates have rarely been comprehensively addressed. Therefore, we provided an updated regional analysis based on validated surface observations. We tested the hypothesis that the recent increasing ozone trends, mostly in urban environments, resulted from intense wildfires driven by extreme meteorological events impacting cities where preexisting volatile organic compound (VOC)-limited regimes dominate. We applied the quantile regression method based on monthly anomalies to estimate trends, quantify their uncertainties and detect trend change points. Additionally, the maximum daily 8 h average (MDA8) and peak-season metrics were used to assess short- and long-term exposure levels, respectively, for the present day (2017–2021). Our results showed lower levels in tropical cities (Bogotá and Quito), varying between 39 and 43 nmol mol−1 for short-term exposure and between 26 and 27 nmol mol−1 for long-term exposure. In contrast, ozone mixing ratios were higher in extratropical cities (Santiago and São Paulo), with a short-term exposure level of 61 nmol mol−1 and long-term exposure levels varying between 40 and 41 nmol mol−1. Santiago (since 2017) and São Paulo (since 2008) exhibited positive trends of 0.6 and 0.3 nmol mol−1 yr−1, respectively, with very high certainty. We attributed these upward trends, or no evidence of variation, such as in Bogotá and Quito, to a well-established VOC-limited regime. However, we attributed the greater increase in the extreme percentile trends (≥ 90th) to heat waves and, in the case of southwestern South America, to wildfires associated with extreme meteorological events. © Author(s) 2024. |
| Paleolimnology of Lago Pichilaguna over the past ∼12,600 years based on a fine-resolution diatom record, northwestern Patagonia (41°S) | Quaternary Science Reviews | Sepúlveda-Zúñiga, E.; Villacís, L.; Maidana, N.; Sagredo, E.; Moreno, P. | 2024 | Agua y Extremos | 10.1016/j.quascirev.2024.108835 | https://doi.org/10.1016/j.quascirev.2024.108835 | art108835 | Vol: 339.0 | 02773791 | Thomson Reuters ISI (SCIE) | | English | The Pacific sector of Northwestern Patagonia (NWP, 40°-44°S) is key for examining the interaction between climate variability, explosive volcanism, and human influences on southern mid-latitude ecosystems. A limited number of studies in this region, however, have focused on aquatic ecosystem and hydrologic balance (HB) changes throughout the Holocene. Here we report a fossil diatom record from Lago Pichilaguna, a small closed-basin lake located in the lowlands of the Chilean Lake District, that reveals prominent changes in species composition and functional groups since ∼12.6 cal ka BP. We interpret positive HB between ∼12.6–11.4 cal ka BP and from ∼5.7 cal ka BP until recent that alternate with negative HB between ∼11.4–6.9 cal ka BP. We observe centennial-scale fluctuations since ∼5.7 cal ka BP that culminate with a negative HB phase over the past ∼270 years. Coherent responses in terrestrial and aquatic ecosystems recorded in the Lago Pichilaguna sediments underscore the influence of variations in the Southern Westerly Winds in NWP from multimillennial to centennial timescales since ∼12.6 cal ka BP. These inferences replicate the timing and direction of changes from previous studies at regional, pan-Patagonian, and zonal scales. The magnitude and rapidity of changes in diatom assemblages that started at ∼0.2 cal ka BP exceeds the ranges of local natural variability since ∼12.6 cal ka BP. This abrupt change is associated with a negative HB phase at centennial timescale, deposition of a tephra layer, and large-scale disturbance by Chilean/European settlers. © 2024 Elsevier Ltd |
| New insights on the interannual surface mass balance variability on the South Shetland Islands glaciers, northerly Antarctic Peninsula | Global and Planetary Change | Torres, C.; Bozkurt, D.; Carrasco-Escaff, T.; Bolibar, J.; Arigony-Neto, J. | 2024 | Agua y Extremos; Zonas Costeras | 10.1016/j.gloplacha.2024.104506 | https://doi.org/10.1016/j.gloplacha.2024.104506 | art104506 | Vol: 239.0 | 09218181 | Thomson Reuters ISI (SCIE) | | English | Few studies have assessed a comprehensive understanding of how the seasonal and interannual variability and trends of the surface mass balance (SMB), including the influence of atmospheric river (ARs), are governed by the climate on the South Shetland Islands (SSI) glaciers located in the northerly Antarctic Peninsula (AP). To address this gap, we comprehensively analyzed the correlations and regressions between seasonal and annual SMB with regional to global climate indices and a state-of-the-art AR tracking database from 1980 to 2019. The daily and monthly SMB was obtained from two physical glaciological models, which was verified against 19 years of annual and seasonal glacier-wide SMB observations available in three glaciers (Johnsons, Hurd, and Bellingshausen), showing a good ability to capture interannual and seasonal variability. Results indicate a low dependence of the SMB on main atmospheric modes of variability (e.g., El Niño-Southern Oscillation and the Southern Annular Mode), and a moderate dependence on regional climate indices based on atmospheric pressure anomalies and sea surface temperature anomalies over the Drake Passage. Furthermore, our findings reveal that ARs have different effects on the SMB depending on the season. For example, winter ARs tend to boost accumulation due to increased snowfall, while summer ARs tend to intensify surface melting due to increased sensible heat flux. Our study highlights the Drake Passage as a key region that has the potential to influence the interannual and seasonal variability of the SMB and other climate variables, such as air temperature and snowfall over the SSI. We suggest that future work should consider this region to better understand the past, present and future climate changes on the SSI and surrounding areas. © 2024 |
| Review article: Drought as a continuum – memory effects in interlinked hydrological, ecological, and social systems | Natural Hazards and Earth System Sciences | Van Loon, A.; Kchouk, S.; Matanó, A.; Tootoonchi, F.; Alvarez-Garreton, C.; Hassaballah, K.; Wu, M.; Wens, M.; Shyrokaya, A.; Ridolfi, E.; Biella, R.; Nagavciuc, V.; Barendrecht, M.; Bastos, A.; Cavalcante, L.; de Vries, F.; Garcia, M.; Mård, J.; Streefkerk, I.; Teutschbein, C.; Tootoonchi, R.; Wees... | 2024 | Agua y Extremos; Cambio de Uso de Suelo | 10.5194/nhess-24-3173-2024 | https://doi.org/10.5194/nhess-24-3173-2024 | 3173-3205 | Vol: 24.0 Issue: 9.0 | 15618633 | Thomson Reuters ISI (SCIE) | Creative Commons Attribution 4.0 International | en | Droughts are often long-lasting phenomena, without a distinct start or end and with impacts cascading across sectors and systems, creating long-term legacies. Nevertheless, our current perceptions and management of droughts and their impacts are often event-based, which can limit the effective assessment of drought risks and reduction of drought impacts. Here, we advocate for changing this perspective and viewing drought as a hydrological–ecological–social continuum. We take a systems theory perspective and focus on how “memory” causes feedback and interactions between parts of the interconnected systems at different timescales. We first discuss the characteristics of the drought continuum with a focus on the hydrological, ecological, and social systems separately, and then we study the system of systems. Our analysis is based on a review of the literature and a study of five cases: Chile, the Colorado River basin in the USA, northeast Brazil, Kenya, and the Rhine River basin in northwest Europe. We find that the memories of past dry and wet periods, carried by both bio-physical (e.g. groundwater, vegetation) and social systems (e.g. people, governance), influence how future drought risk manifests. We identify four archetypes of drought dynamics: impact and recovery, slow resilience building, gradual collapse, and high resilience–big shock. The interactions between the hydrological, ecological, and social systems result in systems shifting between these types, which plays out differently in the five case studies. We call for more research on drought preconditions and recovery in different systems, on dynamics cascading between systems and triggering system changes, and on dynamic vulnerability and maladaptation. Additionally, we advocate for more continuous monitoring of drought hazards and impacts, modelling tools that better incorporate memories and adaptation responses, and management strategies that increase societal and institutional memory. This will help us to better deal with the complex hydrological–ecological–social drought continuum and identify effective pathways to adaptation and mitigation. Copyright: © 2024 Anne F. Van Loon et al. |
| p2 The Extraordinary March 2022 East Antarctica “Heat” Wave. Part II: Impacts on the Antarctic Ice Sheet | Journal of Climate | Wille, J.; Alexander, S.; Amory, C.; Baiman, R.; Barthélemy, L.; Bergstrom, D.; Berne, A.; Binder, H.; Blanchet, J.; Bozkurt, D.; Bracegirdle, T.; Casado, M.; Choi, T.; Clem, K.; Codron, F.; Datta, R.; Di Battista, S.; Favier, V.; Francis, D.; Fraser, A.; Fourré, E.; Garreaud, R.; Genthon, C.; Gorod... | 2024 | Agua y Extremos; Zonas Costeras | 10.1175/JCLI-D-23-0176.1 | https://doi.org/10.1175/JCLI-D-23-0176.1 | 779-799 | Vol: 37.0 Issue: 3.0 | 08948755 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Between 15 and 19 March 2022, East Antarctica experienced an exceptional heat wave with widespread 308–408C temperature anomalies across the ice sheet. In Part I, we assessed the meteorological drivers that generated an intense atmospheric river (AR) that caused these record-shattering temperature anomalies. Here, we continue our large collaborative study by analyzing the widespread and diverse impacts driven by the AR landfall. These impacts included widespread rain and surface melt that was recorded along coastal areas, but this was outweighed by widespread high snowfall accumulations resulting in a largely positive surface mass balance contribution to the East Antarctic region. An analysis of the surface energy budget indicated that widespread downward longwave radiation anomalies caused by large cloud-liquid water contents along with some scattered solar radiation produced intense surface warming. Isotope measurements of the moisture were highly elevated, likely imprinting a strong signal for past climate reconstructions. The AR event attenuated cosmic ray measurements at Concordia, something previously never observed. Last, an extratropical cyclone west of the AR landfall likely triggered the final collapse of the critically unstable Conger Ice Shelf while further reducing an already record low sea ice extent. © 2024 American Meteorological Society. |
| p1 The Extraordinary March 2022 East Antarctica “Heat” Wave. Part I: Observations and Meteorological Drivers | Journal of Climate | Wille, J.; Alexander, S.; Amory, C.; Baiman, R.; Barthélemy, L.; Bergstrom, D.; Berne, A.; Binder, H.; Blanchet, J.; Bozkurt, D.; Bracegirdle, T.; Casado, M.; Choi, T.; Clem, K.; Codron, F.; Datta, R.; Di Battista, S.; Favier, V.; Francis, D.; Fraser, A.; Fourré, E.; Garreaud, R.; Genthon, C.; Gorod... | 2024 | Agua y Extremos; Zonas Costeras | 10.1175/JCLI-D-23-0175.1 | https://doi.org/10.1175/JCLI-D-23-0175.1 | 757-778 | Vol: 37.0 Issue: 3.0 | 08948755 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Between 15 and 19 March 2022, East Antarctica experienced an exceptional heat wave with widespread 30°–40°C temperature anomalies across the ice sheet. This record-shattering event saw numerous monthly temperature records being broken including a new all-time temperature record of -9.4°C on 18 March at Concordia Station despite March typically being a transition month to the Antarctic coreless winter. The driver for these temperature extremes was an intense atmospheric river advecting subtropical/midlatitude heat and moisture deep into the Antarctic interior. The scope of the temperature records spurred a large, diverse collaborative effort to study the heat wave’s meteorological drivers, impacts, and historical climate context. Here we focus on describing those temperature records along with the intricate meteorological drivers that led to the most intense atmospheric river observed over East Antarctica. These efforts describe the Rossby wave activity forced from intense tropical convection over the Indian Ocean. This led to an atmospheric river and warm conveyor belt intensification near the coastline, which reinforced atmospheric blocking deep into East Antarctica. The resulting moisture flux and upper-level warm-air advection eroded the typical surface temperature inversions over the ice sheet. At the peak of the heat wave, an area of 3.3 million km2 in East Antarctica exceeded previous March monthly temperature records. Despite a temperature anomaly return time of about 100 years, a closer recurrence of such an event is possible under future climate projections. In Part II we describe the various impacts this extreme event had on the East Antarctic cryosphere. © 2024 American Meteorological Society. |
| When another one bites the dust: Environmental impact of global copper demand on local communities in the Atacama mining hotspot as registered by tree rings | Science of the Total Environment | Zanetta-Colombo, N.; Scharnweber, T.; Christie, D.; Manzano, C.; Blersch, M.; Gayo, E.; Muñoz, A.; Fleming, Z.; Nüsser, M. | 2024 | Agua y Extremos; Ciudades Resilientes | 10.1016/j.scitotenv.2024.170954 | https://doi.org/10.1016/j.scitotenv.2024.170954 | art170954 | Vol: 920.0 | 00489697 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | Assessing the impact of mining activity on the availability of environmental pollutants is crucial for informing health policies in anticipation of future production scenarios of critical minerals essential for the transition to a net-zero carbon society. However, temporal and spatial monitoring is often sparse, and measurements may not extend far enough back in time. In this study, we utilize variations of chemical elements contained in tree-rings collected in local villages from an area heavily affected by copper mining in the Atacama Desert since the early 20th century to evaluate the temporal distribution of pollutants and their relationship with local drivers. By combining time-varying data on local drivers, such as copper production and the dry tailings deposit area, we show how the surge in copper production during the 1990s, fueled by trade liberalization and increased international demand, led to a significant increment in the availability of metal(loid)s related to mining activities on indigenous lands. Our findings suggest that the environmental legislation in Chile may be underestimating the environmental impact of tailing dams in neighboring populations, affecting the well-being of Indigenous Peoples from the Atacama mining hotspot region. We argue that future changes in production rates driven by international demand could have negative repercussions on the environment and local communities. Therefore, mining emissions and the management of tailing dams should be carefully considered to anticipate their potential negative effects on human and ecosystem health. © 2024 The Authors |
| Advances and knowledge gaps on climate change impacts on honey bees and beekeeping: A systematic review | Global Change Biology | Zapata-Hernández, G.; Gajardo-Rojas, M.; Calderón-Seguel, M.; Muñoz, A.; Yáñez, K.; Requier, F.; Fontúrbel, F.; Ormeño-Arriagada, P.; Arrieta, H. | 2024 | Agua y Extremos | 10.1111/gcb.17219 | https://doi.org/10.1111/gcb.17219 | arte17219 | Vol: 30.0 Issue: 3.0 | 13541013 | Thomson Reuters ISI (SCIE) | | English | The Western honey bee Apis mellifera is a managed species that provides diverse hive products and contributing to wild plant pollination, as well as being a critical component of crop pollination systems worldwide. High mortality rates have been reported in different continents attributed to different factors, including pesticides, pests, diseases, and lack of floral resources. Furthermore, climate change has been identified as a potential driver negatively impacting pollinators, but it is still unclear how it could affect honey bee populations. In this context, we carried out a systematic review to synthesize the effects of climate change on honey bees and beekeeping activities. A total of 90 articles were identified, providing insight into potential impacts (negative, neutral, and positive) on honey bees and beekeeping. Interest in climate change's impact on honey bees has increased in the last decade, with studies mainly focusing on honey bee individuals, using empirical and experimental approaches, and performed at short-spatial (<10 km) and temporal (<5 years) scales. Moreover, environmental analyses were mainly based on short-term data (weather) and concentrated on only a few countries. Environmental variables such as temperature, precipitation, and wind were widely studied and had generalized negative effects on different biological and ecological aspects of honey bees. Food reserves, plant-pollinator networks, mortality, gene expression, and metabolism were negatively impacted. Knowledge gaps included a lack of studies at the apiary and beekeeper level, a limited number of predictive and perception studies, poor representation of large-spatial and mid-term scales, a lack of climate analysis, and a poor understanding of the potential impacts of pests and diseases. Finally, climate change's impacts on global beekeeping are still an emergent issue. This is mainly due to their diverse effects on honey bees and the potential necessity of implementing adaptation measures to sustain this activity under complex environmental scenarios. © 2024 John Wiley & Sons Ltd. |
| The influence of human activities on streamflow reductions during the megadrought in central Chile | Hydrology and Earth System Sciences | Álamos, N.; Alvarez-Garreton, C.; Muñoz, A.; González-Reyes, Á. | 2024 | Agua y Extremos | 10.5194/hess-28-2483-2024 | https://doi.org/10.5194/hess-28-2483-2024 | 2483-2503 | Vol: 28.0 Issue: 11.0 | 10275606 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Since 2010, central Chile has experienced a protracted megadrought with annual precipitation deficits ranging from 25 % to 70 %. An intensification of drought propagation has been attributed to the effect of cumulative precipitation deficits linked to catchment memory. Yet, the influence of water extractions on drought intensification is still unclear. Our study assesses climate and water use effects on streamflow reductions during a high-human-influence period (1988–2020) in four major agricultural basins. We performed this attribution by contrasting observed streamflow (driven by climate and water use) with near-natural streamflow simulations (driven mainly by climate) representing what would have occurred without water extractions. Near-natural streamflow estimations were obtained from rainfall–runoff models trained over a reference period with low human intervention (1960–1988). Annual and seasonal streamflow reductions were examined before and after the megadrought onset, and hydrological drought events were characterized for the complete evaluation period in terms of their frequency, duration, and intensity. Our results show that before the megadrought onset (1988–2009) the mean annual deficits in observed streamflow ranged between 2 % and 20 % across the study basins and that 81 % to 100 % of those deficits were explained by water extractions. During the megadrought (2010–2020), the mean annual deficits in observed streamflow were 47 % to 76 % among the basins. During this time, the relative contribution of precipitation deficits on streamflow reduction increased while the contribution of water extractions decreased, accounting for 27 % to 51 % of the streamflow reduction. Regarding drought events during the complete evaluation period, we show that human activities have amplified drought propagation, with almost double the intensity of hydrological droughts in some basins compared to those expected by precipitation deficits only. We conclude that while the primary cause of streamflow reductions during the megadrought has been the lack of precipitation, water uses have not diminished during this time, causing an exacerbation of the hydrological drought conditions and aggravating their impacts on water accessibility in rural communities and natural ecosystems. © Author(s) 2024. |
| Hydroclimate variability in the Tropical Andes recorded by δ18O isotopes from a new network of Polylepis tarapacana tree-rings | Global and Planetary Change | Álvarez, C.; Christie, D.; González-Reyes, Á.; Veblen, T.; Helle, G.; LeQuesne, C.; Rodriguez-Caton, M.; Szejner, P.; Flores-Sáez, F.; Gipoulou-Zúñiga, T.; Suazo-Álvarez, M.; Muñoz-Salazar, T.; Aliste, D.; Morales, M.; Muñoz, A.; Villalba, R. | 2024 | Agua y Extremos | 10.1016/j.gloplacha.2024.104503 | https://doi.org/10.1016/j.gloplacha.2024.104503 | art104503 | Vol: 239.0 | 09218181 | Thomson Reuters ISI (SCIE) | | English | Stable oxygen isotopes records (δ18O) in tree-rings are commonly used to assess the response of trees to environmental variability being a valuable tool for studying past climate at different temporal and spatial scales. This is particularly relevant in semi-arid regions like the southern Tropical Andes, where ongoing environmental changes coincide with a rapidly increasing demand for hydrological resources, presenting a challenge for ecosystem dynamics and water resource management. In this study, we aim to determine the main spatio-temporal variability of a new network of δ18O Polylepis tarapacana chronologies during the last century, and their relationships with hydroclimate and tropical circulation at local to subcontinental scales throughout the Tropical Andes. For this purpose, we develop six δ18O P. tarapacana tree-ring chronologies across a 450 km latitudinal moisture gradient in the southern Tropical Andes adjacent to the Atacama Desert, covering the period 1900–2007. Results show a clear latitudinal gradient in the δ18O values across the network and significant relationships are observed with other δ18O tree-ring chronologies in Tropical South America, demonstrating clear regional climate influences at a subcontinental scale. A principal component analysis of the δ18O tree-ring chronologies demonstrate a strong regional environmental signal contained in the network, exhibiting a main temporal pattern (PC1 δ18O) that explains 63% of the total variance during the period 1900–2007. Comparisons between PC1 δ18O and environmental variables showed significant negative relationships with precipitation and soil moisture, and positive relationships with temperature and vapor pressure deficit (VPD) during summer when the South American monsoon occurs. The main δ18O tree-ring network signal clearly records tropical atmospheric and circulation patterns across South America. The easterly wind flux conditions from the Amazon basin favor lower δ18O values, and the PC1 δ18O exhibit significant positive correlations with VPD across the entire Tropical Andes and the northern portion of the Amazon basin, and as well as outgoing longwave radiation across the southern Tropical Andes and part of the Amazon basin. The close relationships between the regional signals from our δ18O tree-ring network with the previously mentioned parameters, highlight the potential to develop future hydroclimatic-related reconstructions with these δ18O records to assess climate variability and change across the Tropical Andes. © 2023 |
| Dendroecological analysis of the remote endemic Nothomyrcia fernandeziana forests of Robinson Crusoe Island in the Southeast Pacific | Dendrochronologia | Almonacid, P.; Rojas-Badilla, M.; LeQuesne, C.; Muñoz-Salazar, T.; Christie, D. | 2023 | Agua y Extremos | 10.1016/j.dendro.2023.126129 | https://doi.org/10.1016/j.dendro.2023.126129 | art126129 | Vol: 81 | 11257865 | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | Juan Fernández Archipelago National Park is located in the Southeast Pacific Ocean ∼670 km off the coast of Chile. Composed by three islands, encompasses an ecosystem with 208 native plant species of which 64% are endemic. Robinson Crusoe Island (RCI) is the largest and the only with a permanent human population. Among the tree species of RCI, Nothomyrcia fernandeziana is the most abundant and dominant forming part of this fragile forest ecosystem. Despite this, there is very little information regarding its autoecology and conservation. Therefore, the objective of this work was to determine the radial growth patterns of N. fernandeziana and its longevity using dendrochronological methods. For this purpose, cross sections of trees blown down by wind were collected in conjunction with park rangers from five different sites and analyzed using tree-ring methods. Our results confirm that N. fernandeziana is a shade-tolerant species capable of maintaining extremely low initial growth rates under the canopy for several decades. Individual growth series were found to respond rapidly to changes in environmental conditions, revealed by abrupt positive and negative changes in their annual growth. Our data indicate a longevity of up to 450 years, with one N. fernandeziana individual established in the mid XVII century before the arrival of humans to the pristine island ecosystem. The results of this study are essential to strengthen RCI conservation plans considering restoration actions based on the autoecology of this rare endemic tree species, and the control of exotic invasive species that presently threatens the RCI forests ecosystems. © 2023 Elsevier GmbH |
| Protecting environmental flows to achieve long-term water security | Journal of Environmental Management | Alvarez-Garreton, C.; Boisier, J.; Billi, M.; Lefort, I.; Marinao, R.; Barría, P. | 2023 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.1016/j.jenvman.2022.116914 | https://linkinghub.elsevier.com/retrieve/pii/S0301479722024872 | 116914 | Vol: 328 | 0301-4797 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | In this work, we propose a new approach to diagnose if a water allocation scheme is compatible with long-term water security at the catchment scale, and suggest steps to achieve such compatibility. We argue that when the remaining flow of a river after upstream withdrawals is not sufficient to safeguarding ecological river functions, the basin is at extreme risk of water scarcity, which indicates that the water management is failing. To test this, we analysed the water scarcity risks and the safeguarded environmental flows (e-flows) in 277 basins across a wide range of hydro-climatic conditions in Chile (17–55°S). For each basin, water scarcity risks were assessed based on water stress indices (WSIs, computed as the ratio of withdrawals to water availability), considering two water-use scenarios: (i) WSImax, where total withdrawals correspond to the maximum consumptive water allowed by the law, i.e., where only the e-flows protected by law remain in the river, and (ii) WSIalloc, where total withdrawals correspond to the actual allocated consumptive water uses within the basins. Further, we evaluated the adequacy of the water management system to protect ecological river functions by contrasting the e-flows protected in Chile with those safeguarded in six other countries. The water allocation system in Chile incorporated the protection of minimum e-flows in 2005 and established that these do not exceed 20% of the mean annual streamflow, except in some exceptional cases. This upper limit is consistently lower than the e-flows safeguarded in other countries, where 20%–80% of the mean annual streamflow are protected. This turns out in WSImax values between 80% and 100% in all basins, well above the threshold associated with over-committed basins under extreme risk of water scarcity (70% typically). When moving from the legally allowed to the actually allocated water use scenario, we found contrasting results: about 70% of the basins show low water scarcity risk (WSIalloc <40%), while an 18% have WSIalloc above 100%, indicating the allocation is going beyond current law limits and even beyond physical limits. Our results reveal that the link between e-flows, water allocation and water security has not been adequately incorporated in the current law. E-flows stipulated by law are insufficient to fulfil environmental requirements, while placing the basins under extreme risk of water scarcity if the total allowed withdrawals were exerted. To move towards a system that can effectively achieve long-term water security, we recommend: (i) To define tolerable water scarcity risks for basins, considering environmental requirements. (ii) To translate those risks into measurable basin indices to measure water security, such as the WSI. (iii) To set maximum water use limits (or minimum e-flows) within the basins that are compatible to the water security goals. If, under current and projected water availability conditions, the existing withdrawals exceed these limits, water managers should be able to adapt total consumption to the required limits. © 2022 The Authors |
| Historical Reconstruction of Beekeeping Public Policies in Chile (1968-2022): Transitioning between a Protagonist State, State Withdrawal and Public-Private Articulation; [Reconstrucción histórica de las políticas públicas apícolas en Chile (1968-2022): transitando entre un Estado protagonista, el retiro estatal y la articulación público privada] | Cuadernos de Desarrollo Rural | Calderón-Seguel, M.; Muñoz, A.; Esper, E.; Sánchez, A.; Bravo, J.; Yáñez, K.; Zapata-Hernández, G.; Gajardo-Rojas, M.; Prieto, M.; Marchant Santiago, C.; Urquiza, A. | 2023 | Agua y Extremos; Ciudades Resilientes | 10.11144/Javeriana.cdr20.rhpp | https://doi.org/10.11144/Javeriana.cdr20.rhpp | | Vol: 20.0 | 01221450 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | Spanish | Beekeeping worldwide and in Chile is an activity of great importance for the rural economy, the protection of the melliferous flora and food security, through pollination services. For this reason, international organizations and States consider it a strategic activity for rural development and, accordingly, recent policies formulated in Chile have subscribed to some of these perspectives. There are currently multiple threats to honey bees and other pollinators, which are expressed differently in different countries. Consequently, the study of beekeeping policies is of utmost relevance. In this article, through the analysis of archives and bibliographic sources, a historical reconstruction of the beekeeping policies promoted in Chile between 1968 and 2022 is carried out. Four stages were identified according to institutional designs, thematic orientations and scales of application. It concludes with the main challenges detected for the study of these policies in the country. © 2023, Pontificia Universidad Javeriana. All rights reserved. |
| Climatic control of the surface mass balance of the Patagonian Icefields | Cryosphere | Carrasco-Escaff, T.; Rojas, M.; Garreaud, R.; Bozkurt, D.; Schaefer, M. | 2023 | Agua y Extremos; Zonas Costeras | 10.5194/tc-17-1127-2023 | https://doi.org/10.5194/tc-17-1127-2023 | 1127-1149 | Vol: 17 Issue: 3 | 1994-0416 | Thomson Reuters ISI (SCIE) | | English | The Patagonian Icefields (Northern and Southern Patagonian Icefield) are the largest ice masses in the Andes Cordillera. Despite its importance, little is known about the main mechanisms that underpin the interaction between these ice masses and climate. Furthermore, the nature of large-scale climatic control over the surface mass variations of the Patagonian Icefields still remains unclear. The main aim of this study is to understand the present-day climatic control of the surface mass balance (SMB) of the Patagonian Icefields at interannual timescales, especially considering large-scale processes. We modeled the present-day (1980-2015) glacioclimatic surface conditions for the southern Andes Cordillera by statistically downscaling the output from a regional climate model (RegCMv4) from a 10km spatial resolution to a 450m resolution grid and then using the downscaled fields as input for a simplified SMB model. Series of spatially averaged modeled fields over the Patagonian Icefields were used to derive regression and correlation maps against fields of climate variables from the ERA-Interim reanalysis. Years of relatively high SMB are associated with the establishment of an anomalous low-pressure center near the Drake Passage, the Drake low, that induces an anomalous cyclonic circulation accompanied with enhanced westerlies impinging on the Patagonian Icefields, which in turn leads to increases in the precipitation and the accumulation over the icefields. Also, the Drake low is thermodynamically maintained by a core of cold air that tends to reduce the ablation. Years of relatively low SMB are associated with the opposite conditions. We found low dependence of the SMB on main atmospheric modes of variability (El Niño-Southern Oscillation, Southern Annular Mode), revealing a poor ability of the associated indices to reproduce the interannual variability of the SMB. Instead, this study highlights the Drake Passage as a key region that has the potential to influence the SMB variability of the Patagonian Icefields. © 2023 The Author(s). |
| Freshwater diatom evidence for Southern Westerly Wind evolution since ∼18 ka in northwestern Patagonia | Quaternary Science Reviews | Díaz, C.; Moreno, P.; Villacís, L.; Sepúlveda-Zúñiga, E.; Maidana, N. | 2023 | Agua y Extremos | 10.1016/j.quascirev.2023.108231 | https://doi.org/10.1016/j.quascirev.2023.108231 | art108231 | Vol: 316 | 02773791 | Thomson Reuters ISI (SCIE) | | English | We report a fossil diatom record from small closed-basin Lago Lepué (43°S) to examine past changes in freshwater ecosystems and hydrologic balance in northwestern Patagonia since ∼18 ka. The record starts with abundant staurosiroids and the heavily silicified Aulacoseira granulata suggesting deep turbulent mixing during a low lake level stand between ∼18- 16.4 ka. A. distans increased shortly after ∼16.4 ka and achieved maximum abundance between ∼15.4-13.6 ka, while A. granulata disappeared at ∼15.8 ka and A. alpigena rose at ∼14.9 ka to its maximum between ∼13-12 ka. We infer turbulent, cold, and circumneutral to slightly acid lake conditions contemporaneous with a steady lake level rise that started at ∼16.4 ka and culminated between ∼13-12 ka. These trends reversed between ∼11-7.8 ka with the dominance of Discostella stelligera and staurosiroids, suggesting warmer lake conditions and shallower mixing. Subsequent changes include increases of A. distans with D. stelligera between ∼7.8-5.8 ka, dominance of the former between ∼5.8-3.3 ka, a rapid increase in A. perglabra at ∼3.3 ka, and ensuing diversification of benthic acidophilous species. We infer a rapid lake-level decline between ∼11-7.8 ka, with subsequent rising pulses at ∼7.8 ka and ∼5.8 ka, a multimillennial-scale lake acidification trend, and overall high lake levels with centennial-scale reversals between ∼6-0 ka. Coherent variations in terrestrial and aquatic ecosystem changes recorded in the same core suggest negative hydrologic balance between ∼18-16.4 ka and ∼11–7.8 ka, positive balance between ∼14.9-12 ka and ∼6–0 ka, with transitional conditions in the interim, overprinted by millennial-scale changes and enhanced variability since ∼6 ka. Covariation with paleoclimate records at regional, pan-Patagonian, and hemispheric scale suggests millennial to centennial-scale variability superimposed upon a multi-millennial pacing of Southern Westerly Wind evolution since ∼18 ka. © 2023 Elsevier Ltd |
| The impact of local and climate change drivers on the formation, dynamics, and potential recurrence of a massive fish-killing microalgal bloom in Patagonian fjord | Science of The Total Environment | Díaz, P.; Pérez-Santos, I.; Basti, L.; Garreaud, R.; Pinilla, E.; Barrera, F.; Tello, A.; Schwerter, C.; Arenas-Uribe, S.; Soto-Riquelme, C.; Navarro, P.; Díaz, M.; Álvarez, G.; Linford, P.; Altamirano, R.; Mancilla-Gutiérrez, G.; Rodríguez-Villegas, C.; Figueroa, R. | 2023 | Agua y Extremos; Zonas Costeras | 10.1016/j.scitotenv.2022.161288 | https://linkinghub.elsevier.com/retrieve/pii/S0048969722083929 | 161288 | Vol: 865 | 00489697 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Harmful algal blooms (HABs) in southern Chile are a serious threat to public health, tourism, artisanal fisheries, and aquaculture in this region. Ichthyotoxic HAB species have recently become a major annual threat to the Chilean salmon farming industry, due to their severe economic impacts. In early austral autumn 2021, an intense bloom of the raphidophyte Heterosigma akashiwo was detected in Comau Fjord, Chilean Patagonia, resulting in a high mortality of farmed salmon (nearly 6000 tons of biomass) within 15 days. H. akashiwo cells were first detected at the head of the fjord on March 16, 2021 (up to 478 cells mL−1). On March 31, the cell density at the surface had reached a maximum of 2 × 105 cells mL−1, with intense brown spots visible on the water surface. Strong and persistent high-pressure anomalies over the southern tip of South America, consistent with the positive phase of the Southern Annular Mode (SAM), resulted in extremely dry conditions, high solar radiation, and strong southerly winds. A coupling of these features with the high water retention times inside the fjord can explain the spatial-temporal dynamics of this bloom event. Other factors, such as the internal local physical uplift process (favored by the north-to-south orientation of the fjord), salt-fingering events, and the uplift of subantarctic deep-water renewal, likely resulted in the injection of nutrients into the euphotic layer, which in turn could have promoted cell growth and thus high microalgal cell densities, such as reached by the bloom. © 2022 Elsevier B.V. |
| From lipophilic to hydrophilic toxin producers: Phytoplankton succession driven by an atmospheric river in western Patagonia | Marine Pollution Bulletin | Díaz, P.; Álvarez, G.; Figueroa, R.; Garreaud, R.; Pérez-Santos, I.; Schwerter, C.; Díaz, M.; López, L.; Pinto-Torres, M.; Krock, B. | 2023 | Agua y Extremos | 10.1016/j.marpolbul.2023.115214 | https://doi.org/10.1016/j.marpolbul.2023.115214 | art: 115214 | Vol: 193 | 0025-326X | Thomson Reuters ISI (SCIE) | | English | Phytoplankton succession is related to hydroclimatic conditions. In this study we provide the first description of a toxic phytoplankton succession in the Patagonian Fjord System. The shift was modulated by atmospheric-oceanographic forcing and consisted of the replacement of the marine dinoflagellate Dinophysis acuta in a highly stratified water column during austral summer by the diatom Pseudo-nitzschia calliantha in a mixed water column during late summer and early autumn. This transition, accompanied by a change in the biotoxin profiles (from lipophilic dinophysis toxins to hydrophilic domoic acid), was induced by the arrival of an intense atmospheric river. The winds in Magdalena Sound may have been further amplified, due to its west-east orientation and its location within a tall, narrow mountain canyon. This work also documents the first known appearance of toxic P. calliantha in Northern Patagonian. The potential impacts of the biotoxins of this species on higher trophic levels are discussed. © 2023 Elsevier Ltd |
| The economics impacts of long-run droughts: Challenges, gaps, and way forward | Journal of Environmental Management | Fernández, F.; Vásquez-Lavín, F.; Ponce, R.; Garreaud, R.; Hernández, F.; Link, O.; Zambrano, F.; Hanemann, M. | 2023 | Agua y Extremos; Cambio de Uso de Suelo | 10.1016/j.jenvman.2023.118726 | https://doi.org/10.1016/j.jenvman.2023.118726 | art118726 | Vol: 344 | 03014797 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | Quantifying drought's economic impacts has been key for decision-making to build future strategies and improve the development and implementation of proactive plans. However, climate change is changing drought frequency, intensity, and durability. These changes imply modifications of their economic impact, as longer droughts result in greater cumulative economic losses for water users. Though the longer the drought lasts, other factors also play a crucial role in its economic outcomes, such as Infrastructure capacity (IC), the Amount of Water in Storage (AWS) in reservoirs and aquifers, and short- and long-term responses to it. This study proposes and applies an analytical framework for the economic assessment of long-run droughts, assessing and explaining central Chile megadrought economic effects through the factors that begin to influence the economic impact level in this setting. High levels of both IC and the AWS, as well as short- and long-term responses of water users, allow for high resilience to long-run droughts, tolerating extraordinary water disruption in its society with relatively low total economic impacts. Despite this adaptability, long-term droughts bring places to a water-critical threshold where long-term adaptation strategies may be less flexible than short-term strategies, escalating the adverse economic effects. This fact suggests that the economic evaluation of megadrought needs to focus on future tipping points (substantial water scarcity). The tipping point depends on the IC, how water users manage the AWS, and adaptation strategies. Establishing the tipping point should be a priority for future interdisciplinary research. © 2023 |
| Chilean long-term Socio-Ecological Research Network: progresses and challenges towards improving stewardship of unique ecosystems: Red Chilena de Investigación Socio-Ecológica de Largo Plazo: Avances y desafíos para el manejo responsable de ecosistemas únicos | Revista Chilena de Historia Natural | Frêne, C.; Armesto, J.; Nespolo, R.; Gaxiola, A.; Navarrete, S.; Troncoso, A.; Muñoz, A.; Corcuera, L. | 2023 | Agua y Extremos | 10.1186/s40693-023-00114-4 | https://doi.org/10.1186/s40693-023-00114-4 | art: 1 | Vol: 96 Issue: 1 | 0716-078X | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Ecosystems provide a variety of benefits to human society and humanity’s utilization of ecosystems affects their composition, structure, and functions. Global change drivers demand us to study the interactions between ecological and social systems, and advise strategies to protect the large fraction of Chilean unique ecosystems. Long-term research and monitoring are vital for meaningful understanding of human impacts and socio-ecological feedback, which occur over multiple spatial and time-scales and can be invisible to traditional grant-sponsored short-term studies. Despite the large fraction of unique ecosystems, Chilean government agencies have not established long-term monitoring programs to inform and guide management decisions for use, conservation, and adaptation to climate change. Responding to this void, the Chilean Long-Term Socio-Ecological Research Network (LTSER-Chile) was created, comprising nine study sites funded by a variety of private and public institutions, that broadly seeks to understand how global change is altering biodiversity and ecosystem functions. The LTSER-Chile is currently in a phase of institutional consolidation to achieve its objectives of alignment with international efforts, fill the need for high-quality, long-term data on social, biological and physical components of Chilean ecosystems, and develop itself as an open research platform for the world. Despite the wide diversity of ecosystems ecncompased by LTSER-Chile sites, several common variables are monitored, especially climatic and hydrographic variables and many ecological indicator variables that consider temporal fluctuations, population and community dynamics. The main challenges currently facing the LTSER-Chile are to secure funding to maintain existing long-term monitoring programs, to persuade public and private decision-makers about its central role in informing and anticipating socio-ecological problems, and to achieve greater ecosystem representation by integrating new long-term study sites. This will require a more decisive political commitment of the State, to improve the stewardship of our unique terrestrial and marine ecosystems, and the realization that sound ecologically-sustainable policies will never be possible without a national monitoring network. We argue that the State should build on LTSER and several other private and university initiatives to provide the country with a monitoring network. In the absence of this commitment, the LTSER system is subject to discontinuity and frequent interruptions, which jeopardizes the long-term effort to understand the functioning of nature and its biodiversity. © 2023, The Author(s). |
| Cooling the Coldest Continent The 4 December 2021 Total Solar Eclipse over Antarctica | Bulletin of the American Meteorological Society | Garreaud, R.; Bozkurt, D.; Spangrude, C.; Carrasco-Escaff, T.; Rondanelli, R.; Muñoz, R.; Jubier, X.; Lazzara, M.; Keller, L.; Rojo, P. | 2023 | Agua y Extremos; Zonas Costeras | 10.1175/BAMS-D-22-0272.1 | https://doi.org/10.1175/BAMS-D-22-0272.1 | E2265-E2285 | Vol: 104 Issue: 12 | 00030007 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Total solar eclipses (TSEs) are impressive astronomical events that have attracted people’s curiosity since ancient times. Their abrupt alterations to the radiation balance have stimulated studies on “eclipse meteorology,” most of them documenting events in the Northern Hemisphere while only one TSE (23 November 2003) has been described over Antarctica. On 4 December 2021—just a few days before the austral summer solstice—the moon blocked the sun over the austral high latitudes, with the path of totality arching from the Weddell Sea to the Amundsen Sea, thus producing a ∼2-min central TSE. In this work we present high-resolution meteorological observations from Union Glacier Camp (80°S, 83°W), the only location with a working station under totality, and South Pole station. These observations were complemented with meteorological records from 37 surface stations across Antarctica. Notably, the largest cooling (∼5°C) was observed over the East Antarctic dome, where obscurity was ∼85% while many sectors experienced insignificant temperature changes. This heterogenous cooling distribution, at odds with the seemingly homogeneous land surface of Antarctica, is partially captured by a simple radiative model. To further diagnose the effect of the eclipse on the surface meteorology, we ran multiple pairs of simulations (eclipse enabled and disabled) using the Weather Research and Forecasting (WRF) Model. The overall pattern and magnitude of the simulated cooling agree well with the observations and reveal that, in addition to the solar radiation deficit and cloud cover, low-level winds and the height of the planetary boundary layer are key determinants of the temperature changes and their spatial variability. © 2023 American Meteorological Society. This published article is licensed under the terms of the default AMS reuse license. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses). |
| Evolution of heatwaves in Chile since 1980 | Weather and Climate Extremes | González-Reyes, Á.; Jacques-Coper, M.; Bravo, C.; Rojas, M.; Garreaud, R. | 2023 | Agua y Extremos; Zonas Costeras | 10.1016/j.wace.2023.100588 | https://doi.org/10.1016/j.wace.2023.100588 | art100588 | Vol: 41 | 22120947 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Heatwaves (HWs) are highly dangerous threats to human and ecosystem health, as well as to many economic sectors around the world. In the present work focused on Chile, we use a high-resolution (∼5 km) gridded product (CR2Met v2.0) to evaluate the spatiotemporal distribution and trends of HWs. We analyze daily maximum temperatures (Tx) from late austral spring to early autumn (November to March) to evaluate the HWs behavior during 1980–2020, using three criteria: i) three consecutive days with Tx > 30°C, ii) three consecutive days with Tx > 90th percentile (P90), and iii) three consecutive days with Tx > 95th percentile (P95). We validated our results using HWs statistics based on eighteen official meteorological stations; this procedure revealed a coherence with gridded data mainly over the Central Valley and the Andes. Using the P90 threshold, we found upward trends across the Andes between 20° and 36°S (>1 events per decade), and in the Central Valley between 34° - 43°S (>0.75 events per decade). In addition, using the P90 and P95 thresholds, HWs exhibit upward trends (>1 and 0.5 events per decade, respectively) throughout most of Chile, including Andes and Patagonia. Moreover, using all thresholds, we found an increase in HW frequency during the 2011–2020 megadrought period (ranging from 1 to 4 HWs events/decade) in comparison to the previous period (1980–2010). Meteorological factors such as an increase in the frequency of Puelche (Föhn-like) winds are proposed as an amplifying mechanism of HWs in South-Central Chile. © 2023 |
| Earth system justice needed to identify and live within Earth system boundaries | Nature Sustainability | Gupta, J.; Liverman, D.; Prodani, K.; Aldunce, P.; Bai, X.; Broadgate, W.; Ciobanu, D.; Gifford, L.; Gordon, C.; Hurlbert, M.; Inoue, C.; Jacobson, L.; Kanie, N.; Lade, S.; Lenton, T.; Obura, D.; Okereke, C.; Otto, I.; Pereira, L.; Rockström, J.; Scholtens, J.; Rocha, J.; Stewart-Koster, B.; David T... | 2023 | Agua y Extremos | 10.1038/s41893-023-01064-1 | https://doi.org/10.1038/s41893-023-01064-1 | 630-638 | Vol: 6 | 2398-9629 | Thomson Reuters ISI (SCIE; SSCI) | | English | Living within planetary limits requires attention to justice as biophysical boundaries are not inherently just. Through collaboration between natural and social scientists, the Earth Commission defines and operationalizes Earth system justice to ensure that boundaries reduce harm, increase well-being, and reflect substantive and procedural justice. Such stringent boundaries may also affect ‘just access’ to food, water, energy and infrastructure. We show how boundaries may need to be adjusted to reduce harm and increase access, and challenge inequality to ensure a safe and just future for people, other species and the planet. Earth system justice may enable living justly within boundaries. © 2023, Springer Nature Limited. |
| Panta Rhei benchmark dataset: socio-hydrological data of paired events of floods and droughts | Earth System Science Data | Kreibich, H.; Schröter, K.; Di Baldassarre, G.; Van Loon, A.; Mazzoleni, M.; Abeshu, G.; Agafonova, S.; Aghakouchak, A.; Aksoy, H.; Alvarez-Garreton, C.; Aznar, B.; Balkhi, L.; Barendrecht, M.; Biancamaria, S.; Bos-Burgering, L.; Bradley, C.; Budiyono, Y.; Buytaert, W.; Capewell, L.; Carlson, H.; Ca... | 2023 | Agua y Extremos | 10.5194/essd-15-2009-2023 | https://doi.org/10.5194/essd-15-2009-2023 | 2009-2023 | Vol: 15 Issue: 5 | 1866-3508 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | As the adverse impacts of hydrological extremes increase in many regions of the world, a better understanding of the drivers of changes in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is currently a lack of comprehensive, empirical data about the processes, interactions, and feedbacks in complex human-water systems leading to flood and drought impacts. Here we present a benchmark dataset containing socio-hydrological data of paired events, i.e. two floods or two droughts that occurred in the same area. The 45 paired events occurred in 42 different study areas and cover a wide range of socio-economic and hydro-climatic conditions. The dataset is unique in covering both floods and droughts, in the number of cases assessed and in the quantity of socio-hydrological data. The benchmark dataset comprises (1) detailed review-style reports about the events and key processes between the two events of a pair; (2) the key data table containing variables that assess the indicators which characterize management shortcomings, hazard, exposure, vulnerability, and impacts of all events; and (3) a table of the indicators of change that indicate the differences between the first and second event of a pair. The advantages of the dataset are that it enables comparative analyses across all the paired events based on the indicators of change and allows for detailed context- and location-specific assessments based on the extensive data and reports of the individual study areas. The dataset can be used by the scientific community for exploratory data analyses, e.g. focused on causal links between risk management; changes in hazard, exposure and vulnerability; and flood or drought impacts. The data can also be used for the development, calibration, and validation of socio-hydrological models. The dataset is available to the public through the GFZ Data Services (Kreibich et al., 2023, 10.5880/GFZ.4.4.2023.001). © 2023 Heidi Kreibich et al. |
| Recent Deoxygenation of Patagonian Fjord Subsurface Waters Connected to the Peru–Chile Undercurrent and Equatorial Subsurface Water Variability | Global Biogeochemical Cycles | Linford, P.; Pérez‐Santos, I.; Montes, I.; Dewitte, B.; Buchan, S.; Narváez, D.; Saldías, G.; Pinilla, E.; Garreaud, R.; Díaz, P.; Schwerter, C.; Montero, P.; Rodríguez‐Villegas, C.; Cáceres‐Soto, M.; Mancilla‐Gutiérrez, G.; Altamirano, R. | 2023 | Agua y Extremos | 10.1029/2022GB007688 | https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GB007688 | e2022GB007688 | Vol: 37 Issue: 6 | 0886-6236, 1944-9224 | Thomson Reuters ISI (SCIE) | | English | In recent decades, global dissolved oxygen (DO) measurements have registered a decrease of ∼1%–2% in oxygen content, raising concerns regarding the negative impacts of ocean deoxygenation on marine life and the greenhouse gas cycle. By combining in situ data from 2016 to 2022, satellite remote sensing, and outputs from a physical-biogeochemical model, we revealed the deoxygenation process in the Patagonian fjords for the first time. Deoxygenation was associated with the advection of equatorial subsurface water (ESSW) mass into the northern region of Patagonia. An analysis of the circulation regime using the Mercator-Ocean global high-resolution model confirmed the importance of the Peru–Chile undercurrent (PCUC) in transporting the ESSW poleward, contributing to the entrance of ESSW into the northern Patagonian fjords. A mooring system installed in the water interchange area between the Pacific Ocean and Patagonian fjords detected a decreasing DO of −21.66 μmol L−1 over 7 years, which was explained by the increase in PCUC transport of 1.46 Sv. Inside the Puyuhuapi fjord system, a second DO time series exhibited more marked deoxygenation with −88.6 μmol L−1 over 3 years linked with the influence of ESSW and local processes, such as DO consumption by the organic matter degradation. The recent deoxygenation registered in the northern Patagonian fjords demonstrates the significance of studying DO in the context of reducing the global oxygen content, further warranting the quantification of the impacts of deoxygenation on life cycles of marine organisms that inhabit the Patagonian fjords and channels and the Humboldt current system. © 2023. American Geophysical Union. All Rights Reserved. |
| Extreme harmful algal blooms, climate change, and potential risk of eutrophication in Patagonian fjords: Insights from an exceptional Heterosigma akashiwo fish-killing event | Progress in Oceanography | Mardones, J.; Paredes-Mella, J.; Flores-Leñero, A.; Yarimizu, K.; Godoy, M.; Artal, O.; Corredor-Acosta, A.; Marcus, L.; Cascales, E.; Pablo Espinoza, J.; Norambuena, L.; Garreaud, R.; González, H.; Iriarte, J. | 2023 | Agua y Extremos | 10.1016/j.pocean.2022.102921 | https://www.sciencedirect.com/science/article/pii/S007966112200180X | 102921 | Vol: 210 | 00796611 | Thomson Reuters ISI (SCIE) | | English | The Patagonian fjords have experienced intense harmful algal blooms (HABs) in the last decade, affecting important aquaculture areas in southern Chile. Climatic anomalies have recently triggered ‘super blooms’ of opportunistic toxic microalgal genera, especially due to persistent thermal stratification which likely provides an optimal niche for HABs development in fjord systems. In March-April 2021, an intense and widespread bloom of the raphidophyte Heterosigma akashiwo caused high salmon mortalities (>6,000 t) in the Comau fjord, Los Lagos Region. A climate variability analysis showed the effects of the positive phase of the Southern Annular Mode (SAM > 1.2 hPa) overcame those of La Niña (Niño3.4 = -0.9 °C) leading to an intense drought on the northern part of Patagonia with record low rainfall (the 2nd driest summer in the last 70 years) and increased water temperature. A regional satellite analysis revealed an extreme and persistent shallow Mixed Layer Depth (MLD) during summer periods since 2019 within the inland seas. In situ vertical fine-resolution measurements during the bloom event showed high cell abundances in the first 3 m of the water column (max. ∼ 70,000 cells mL−1), associated with warmer water temperature (∼15.5 – 17.5 °C), low salinity (∼25–30 psu), moderate to high dissolved oxygen (5 – 8.5 mg/L) and extremely high fluorescence signals in dense superficial cell aggregations (max. 74.9 µg/L). A 18S rRNA metabarcoding analysis formally confirmed the presence of H. akashiwo and its almost monospecific bloom development at the water surface. HPLC pigment analysis showed the carotenoid fucoxanthin in high proportion (48.8 %) compared to other photosynthetic pigments, becoming a potential pigment biomarker for early satellite H. akashiwo detection. Cell growth and cytotoxic in vitro experiments revealed high phenotypic plasticity of Chilean H. akashiwo against sudden changes in salinity. An RTgill-W1 gill cell assay revealed high cytotoxic activity (viability down to ∼ 50 – 30 % of controls) only at high cell abundances (>40,000H. akashiwo cells mL−1), which was in accordance with histological examination of moribund salmon that showed gill damage and circulatory disorders mainly due to long-term exposure to hypoxic conditions and not to potent cytotoxic effects. The Party-MOSA particles dispersion model revealed a high retention of water masses within the Comau fjord during the H. akashiwo outbreak, a scenario that may have boosted fish kills due to enhanced cells patchiness, ichthyotoxins persistence and hypoxic conditions. A historical dissolved inorganic nutrient data analysis showed that inner Patagonian fjords maintain low N and P concentrations including those environments considered of high eutrophication risk. Low N:P (<16:1) ratios measured at Comau fjord during the 2021 suggests that toxic flagellates growth could be favored over diatoms; however, low N:Si (<1:1 – N deficiency) evidences a clear need for better understanding of the role of mixotrophy in the persistence of the 2021H. akashiwo bloom for several weeks. These results highlight the fact that HABs responses against climate drivers and potential eutrophication are not universal and need to be assessed yearly and locally, particularly because extreme droughts and intensive aquaculture in northern Patagonia are expected to continue throughout the 21st century. © 2022 Elsevier Ltd |
| Widespread synchronous decline of Mediterranean-type forest driven by accelerated aridity | Nature Plants | Miranda, A.; Syphard, A.; Berdugo, M.; Carrasco, J.; Gómez-González, S.; Ovalle, J.; Delpiano, C.; Vargas, S.; Squeo, F.; Miranda, M.; Dobbs, C.; Mentler, R.; Lara, A.; Garreaud, R. | 2023 | Agua y Extremos; Cambio de Uso de Suelo | 10.1038/s41477-023-01541-7 | https://doi.org/10.1038/s41477-023-01541-7 | 1810-1817 | Vol: 9 Issue: 11 | 20550278 | Thomson Reuters ISI (SCIE) | | English | Large-scale, abrupt ecosystem change in direct response to climate extremes is a critical but poorly documented phenomenon1. Yet, recent increases in climate-induced tree mortality raise concern that some forest ecosystems are on the brink of collapse across wide environmental gradients2,3. Here we assessed climatic and productivity trends across the world’s five Mediterranean forest ecosystems from 2000 to 2021 and detected a large-scale, abrupt forest browning and productivity decline in Chile (>90% of the forest in <100 days), responding to a sustained, acute drought. The extreme dry and warm conditions in Chile, unprecedented in the recent history of all Mediterranean-type ecosystems, are akin to those projected to arise in the second half of the century4. Long-term recovery of this forest is uncertain given an ongoing decline in regional water balance. This dramatic plummet of forest productivity may be a spyglass to the future for other Mediterranean ecosystems. © 2023, The Author(s), under exclusive licence to Springer Nature Limited. |
| Drought increase since the mid-20th century in the northern South American Altiplano revealed by a 389-year precipitation record | Climate of the Past | Morales, M.; Crispín-DelaCruz, D.; Álvarez, C.; Christie, D.; Ferrero, M.; Andreu-Hayles, L.; Villalba, R.; Guerra, A.; Ticse-Otarola, G.; Rodríguez-Ramírez, E.; LLocclla-Martínez, R.; Sanchez-Ferrer, J.; Requena-Rojas, E. | 2023 | Agua y Extremos | 10.5194/cp-19-457-2023 | https://cp.copernicus.org/articles/19/457/2023/ | 457-476 | Vol: 19 Issue: 2 | 1814-9324 | Thomson Reuters ISI (SCIE) | | English | Abstract. Given the short span of instrumental precipitation
records in the South American Altiplano, longer-term hydroclimatic records
are needed to understand the nature of climate variability and to improve
the predictability of precipitation, a key natural resource for the
socioeconomic development in the Altiplano and adjacent arid lowlands. In
this region grows Polylepis tarapacana, a long-lived tree species that is very sensitive to
hydroclimatic changes and has been widely used for tree-ring studies in the
central and southern Altiplano. However, in the northern sector of the
Peruvian and Chilean Altiplano (16–19∘ S)
still exists a gap of high-resolution hydroclimatic data based on tree-ring
records. Our study provides an overview of the temporal evolution of the
late-spring–mid-summer precipitation for the period 1625–2013 CE at the
northern South American Altiplano, allowing for the identification of wet or
dry periods based on a regional reconstruction from three P. tarapacana chronologies. An
increase in the occurrence of extreme dry events, together with a decreasing
trend in the reconstructed precipitation, has been recorded since the 1970s
in the northern Altiplano within the context of the last ∼4 centuries. The average precipitation over the last 17 years stands out
as the driest in our 389-year reconstruction. We reveal a temporal and
spatial synchrony across the Altiplano region of dry conditions since the
mid-1970s. Independent tree-ring-based hydroclimate reconstructions and
several paleoclimatic records based on other proxies available for the
tropical Andes record this synchrony. The influence of El Niño–Southern
Oscillation (ENSO) on the northern Altiplano precipitation was detected by
our rainfall reconstruction that showed past drier conditions in our study
region associated with ENSO warm events. The spectral properties of the
rainfall reconstruction showed strong imprints of ENSO variability at
decadal, sub-decadal, and inter-annual timescales, in particular from the
Pacific NIÑO 3 sector. Overall, the recent reduction in precipitation in
comparison with previous centuries, the increase in extreme dry events and
the coupling between precipitation and ENSO variability reported by this
work is essential information in the context of the growing demand for water
resources in the Altiplano. This study will contribute to a better
understanding of the vulnerability and resilience of the region to the
projected evapotranspiration increase for the 21st century associated with
global warming. |
| Environmental evolution of western Tierra del Fuego (∼54°S) since ice-free conditions and its zonal/hemispheric implications | Quaternary Science Reviews | Moreno, P.; Lambert, F.; Hernández, L.; Villa-Martínez, R. | 2023 | Agua y Extremos; Ciudades Resilientes | 10.1016/j.quascirev.2023.108387 | https://doi.org/10.1016/j.quascirev.2023.108387 | art108387 | Vol: 322 | 02773791 | Thomson Reuters ISI (SCIE) | | English | By virtue of its position adjacent to the Drake Passage, Tierra del Fuego in South America allows examining the vegetation and environmental history of the southernmost continental landmass outside Antarctica, and the evolution of the Southern Westerly Winds-Southern Ocean (SWW–SO) coupled system since the Last Glacial Maximum (LGM). For that purpose, we studied sediment cores from Lago Charquito, a small closed-basin lake in central-west Tierra del Fuego with a continuous lacustrine record since ∼17.3 ka. Ice-free conditions at the site imply a ∼70 km retreat of the Bahía Inútil glacier lobe from its LGM position during a ∼800-year interval, a trend that continued until its disappearance ∼100 km upstream from L. Charquito, ∼800 years later. Our palynological data show an open landscape dominated by cold-tolerant shrubs and herbs between ∼17.3–12.9 ka, with increases in precipitation of SWW origin at ∼16.3 ka, ∼14.7 ka, between ∼8.7–7.6 ka, and after ∼6.8 ka. Warming at ∼12.9 ka initiated an abrupt afforestation trend that stalled during the early Holocene (∼12–8.7 ka) owing to a precipitation decline and wildfires, and later resumed in response to invigorated SWW. We hypothesize that sparse Nothofagus tree populations inhabited the periphery of the Patagonian Ice Sheet (PIS) during the LGM and migrated toward the Andes contemporaneous with glacier recession as temperature rose during the Last Glacial Termination (T1). We posit that besides establishing topographic and climatic barriers for land biota, the PIS enabled the connectivity of cold-tolerant hygrophilous plant populations along a humid fringe adjacent to its land-based perimeter, despite the presumably dry conditions downwind from the eastern PIS margin. Our results suggest that southward shifts or expansion of the SWW toward or beyond Tierra del Fuego enhanced upwelling and ventilation of deep waters in the SO, northward shifts or weakening had the opposite effect. We observe that the time evolution of atmospheric CO2 concentrations, high-latitude air and sea-surface temperatures, and sea level during T1 fall short in explaining the timing and abruptness of the Bahía Inútil glacier lobe collapse, and quite possibly multiple other glacier lobes from the PIS. © 2023 Elsevier Ltd |
| Fires and rates of change in the temperate rainforests of northwestern Patagonia since ∼18 ka | Quaternary Science Reviews | Moreno, P.; Méndez, C.; Henríquez, C.; Fercovic, E.; Videla, J.; Reyes, O.; Villacís, L.; Villa-Martínez, R.; Alloway, B. | 2023 | Agua y Extremos | 10.1016/j.quascirev.2022.107899 | https://www.sciencedirect.com/science/article/pii/S0277379122005303?via%3Dihub | 107899 | Vol: 300 | 02773791 | Thomson Reuters ISI (SCIE) | | English | We examine the temporal and spatial structure of wildfires and rates of vegetation change in the Pacific sector of northwestern Patagonia (40°-44°S) over the last ∼18,000 years. Macroscopic Charcoal Accumulation Rates (CHAR), a proxy of past local fires, shows a geographic variation that mirrors the modern north-to-south and low-to-high elevation increase in annual precipitation and decrease in precipitation seasonality, and the frequency of explosive volcanic events. Variability in past fires is evident at multiple timescales, with a significant multi-millennial low between ∼18–13.1 ka, an abrupt rise between ∼13.1–12.5 ka, and heightened fire activity between ∼11.4–8.2 ka with significant high values between ∼10–9.4 ka. A subsequent decline led to the lowest Holocene values between ∼6–5.4 ka, which rose and led to significant high values between ∼3.1 ka and the present. Andean and Western Upwind Environments share a multi-millennial structure of fire activity since ∼18 ka, overprinted by millennial and centennial-scale divergences. These differences underscore the role of explosive volcanism as a trigger or modulator of fire activity in the vicinity of Andean eruptive centers. We posit that fire activity in Western Upwind Environments was driven primarily by hydroclimate variations, namely changes in the intensity of the Southern Westerly Winds. Compilations of CHAR and the Rates of Change (ROC) parameter, a measure of the magnitude and rapidity of changes in the pollen records, covary during the onset of the interglacial fire regime at ∼13.1 ka and the last ∼4000 years, suggesting that fires catalyzed vegetation changes during specific intervals since the last glaciation. Highly mobile human occupations deployed along the coasts started at ∼6.2 ka, increased in pulses, and spread widely during the last two millennia. Covariation with CHAR and ROC since ∼4 ka suggests that hunter-gatherer-fishers contributed to enhanced fire activity and abrupt vegetation changes at regional scale. The ubiquitous fire maximum over the last four centuries relates to widespread settlement and associated large-scale land clearance conducted by European/Chilean settlers. © 2022 Elsevier Ltd |
| Multiproxy Approach to Reconstruct the Fire History of Araucaria araucana Forests in the Nahuelbuta Coastal Range, Chile | Forests | Muñoz, A.; González, M.; Schneider-Valenzuela, I.; Klock-Barría, K.; Madariaga-Burgos, M.; Rodríguez, C.; Abarzúa, A.; Solari, M.; Martel-Cea, A.; Velásquez, B.; Paredes, B.; Guerrero, F.; Montiel, M.; Tapia-Marzán, V.; Riquelme, T.; Sheppard, P. | 2023 | Agua y Extremos; Cambio de Uso de Suelo | 10.3390/f14061082 | https://doi.org/10.3390/f14061082 | art1082 | Vol: 14 Issue: 6 | 19994907 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Multiproxy reconstructions of fire regimes in forest ecosystems can provide a clearer understanding of past fire activity and circumvent some limitations of single proxy reconstructions. While inferring fire history from scars in trees is the most precise method to reconstruct temporal fire patterns, this method is limited in Araucaria araucana forests by rot after fire injuries, successive fires that destroy the evidence and the prohibition of sample extraction from living Araucaria trees. In this context, dendrochemical studies in Araucaria trees and charcoal analysis from sediment cores can complement and extend the time perspective of the fire history in the relictual Araucaria-Nothofagus forests of the coastal range. We used dendrochemical, fire scar and charcoal records from the Nahuelbuta Coastal Range (37.8° S; 73° W) spanning the last 1000 years to reconstruct the fire history. The results indicate that periods with higher fire activity occurred between 1400 and 1650 AD. Long-term changes in the fire regime are related to increased climate variability over the last 1000 years, and especially with the arrival of settlers to the area after 1860 CE. The most severe fire events in the Nothofagus and Araucaria forests occurred when suitable fire-prone conditions were superimposed with high human densities. © 2023 by the authors. |
| New Observations of the Meteorological Conditions Associated with Particulate Matter Air Pollution Episodes in Santiago, Chile | Atmosphere | Muñoz-M, R.; Garreaud, R.; Rutllant, J.; Seguel, R.; Corral, M. | 2023 | Agua y Extremos; Ciudades Resilientes | 10.3390/atmos14091454 | https://doi.org/10.3390/atmos14091454 | art1454 | Vol: 14 Issue: 9 | 20734433 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The meteorological factors of the severe wintertime particulate matter (PM) air pollution problem of the city of Santiago, Chile, are investigated with newly available observations, including a 30 m tower measuring near-surface stability, winds and turbulence, as well as lower-tropospheric vertical profiles of temperature and winds measured by commercial airplanes operating from the Santiago airport (AMDAR database). Focusing on the cold season of the years 2017–2019, high-PM days are defined using an index of evening concentrations measured in the western part of the city. The diurnal cycles of the different meteorological variables computed over 25 PM episodes are compared against the overall diurnal cycles. PM episodes are associated with enhanced surface stability and weaker surface winds and turbulence during the evening and night. AMDAR vertical profiles of temperature and winds during episodes reveal a substantial lower-tropospheric warming attributed to enhanced regional subsidence, which is consistent with the shallower daytime boundary layer depth and the increased surface thermal amplitude observed during these days. An explanation for the weak surface winds during PM episodes was not evident, considering that these are clear days that would strengthen the local valley wind system. Two possible mechanisms are put forward to resolve this issue, which can be tested in the future using high-resolution numerical modeling validated with the new data described here. © 2023 by the authors. |
| The international and historical dimensions of Chilean water bureaucracy | Water International | Nicolas-Artero, C. | 2023 | Agua y Extremos | 10.1080/02508060.2023.2220512 | https://doi.org/10.1080/02508060.2023.2220512 | 480-499 | Vol: 48 Issue: 4 | 02508060 | Thomson Reuters ISI (SCIE) | | English | This article explores the global dimension of Chilean water bureaucracy through the lens of its peripheral global position. The study relies on historical sources and identifies three periods. The first period extends from the end of World War II to the 1973 military coup. During this time, the establishment of water policies, influenced by multilateral and direct US aid, resulted in the formation of a water bureaucracy. US influence persisted during the dictatorship (1973-1990) due to support for the military junta. Since the transition to democracy, the water bureaucracy has relied on foreign capital to implement various water policies. © 2023 International Water Resources Association. |
| Irrigated systems in Chile: towards the end of water turns?; [Les systèmes irrigués au Chili: vers la fin des tours d'eau ?] | Cahiers Agricultures | Nicolas-Artero, C. | 2023 | Agua y Extremos | 10.1051/cagri/2023021 | https://doi.org/10.1051/cagri/2023021 | art29 | Vol: 32 | 11667699 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | This paper studies the transformation of irrigated systems in the semi-arid Elqui Valley in Chile. We use the notion of hydrosocial territory to analyze the effects of new hydraulic infrastructures on irrigation practices and institutional water rules. The methodology is based on the collection and analysis of qualitative and quantitative data. The installation of new infrastructures associated with the rise of commercial agriculture, financed by the State, leads to a gradual abandonment of canals and water turns and disintegrates the collective decision-making process within the irrigators'associations. © C.N. Nicolas-Artero, Hosted by EDP Sciences 2023. |
| Volatile organic compounds measured by proton transfer reaction mass spectrometry over the complex terrain of Quintero Bay, Central Chile | Environmental Pollution | Seguel, R.; Garreaud, R.; Muñoz, R.; Bozkurt, D.; Gallardo, L.; Opazo, C.; Jorquera, H.; Castillo, L.; Menares, C. | 2023 | Agua y Extremos; Ciudades Resilientes; Zonas Costeras | 10.1016/j.envpol.2023.121759 | https://doi.org/10.1016/j.envpol.2023.121759 | 121759 | Vol: 330 | 02697491 | Thomson Reuters ISI (SCIE) | | English | This research provides new evidence regarding the different kinds of air quality episodes, and their underlying mechanisms, that frequently impact the urban area of Quintero Bay in Central Chile, which is located along complex coastal terrain and is surrounded by industries. The monitoring campaign was carried out in January 2022 and encompassed two distinctive meteorological regimes. The first part of the month was dominated by a coastal low centered to the south of Quintero, which resulted in prevailing northerly flow (or weak southerlies) and a deep cloud-topped marine boundary layer. After a 2–3-day transition, the latter collapsed, and a clear-sky regime ensued, which was characterized by a shallow boundary layer and strong southerly winds during the daytime that lasted until the end of the campaign. By using proton transfer reaction time of flight mass spectrometry (PTR–TOF–MS) at a high temporal resolution (1 s), we measured high levels of volatile organic compounds (VOCs) during air quality episodes in real time. The episodes detected were associated with different prevailing meteorological regimes, suggesting that different point sources were involved. In the first episode, propene/cyclopropane, butenes, benzene, toluene and ethylbenzene/xylenes were associated with north and northwesterly weak winds. Complaints associated with hydrocarbon odor were reported. The pollution originated from industrial and petrochemical units located to the north of Quintero, which transport and store natural gas, liquified petroleum gas and oil. The second episode was linked to an oil refinery located south of our measurement site. In this case, high levels of phenol, furan and cresols occurred under strong southwesterly winds. During this event, headaches and dizziness were reported. By contrast, the levels of other aromatic compounds (benzene, toluene, ethylbenzene/xylenes) were lower than in the first air pollution episode. © 2023 Elsevier Ltd |
| Ecosystem services of Chilean sclerophyllous forests and shrublands on the verge of collapse: A review | Journal of Arid Environments | Smith-Ramírez, C.; Grez, A.; Galleguillos, M.; Cerda, C.; Ocampo-Melgar, A.; Miranda, M.; Muñoz, A.; Rendón-Funes, A.; Díaz, I.; Cifuentes, C.; Alaniz, A.; Seguel, O.; Ovalle, J.; Montenegro, G.; Saldes-Cortés, A.; Martínez-Harms, M.; Armesto, J.; Vita, A. | 2023 | Agua y Extremos; Cambio de Uso de Suelo | 10.1016/j.jaridenv.2022.104927 | https://www.sciencedirect.com/science/article/pii/S0140196322002221 | 104927 | Vol: 211 | 01401963 | Thomson Reuters ISI (SCIE) | | English | Dryland forests are the areas most threatened by climate change, urbanization and land-use change simultaneously. Ecosystem services provided by Mediterranean dryland forests are have been in steep decline, and are extensively studied in the Mediterranean basin, however considerably less in other areas with Mediterranean climates. Knowledge of these services is necessary for the promotion of their conservation and restoration. Here, we synthesize current knowledge regarding the main ecosystem services provided by Chilean Mediterranean sclerophyllous forests and shrublands (SFSh). This knowledge allows for the valuation of SFSh in order to conserve, restore and study them. We found 158 studies, including technical reports, theses, and scientific literature regarding the social and environmental benefits derived from Chilean SFSh, though many did not use the term “ecosystem services” (ES). We found data on 19 ecosystem services with four or more studies per service. ES studies in Chile increased in number a couple years after Millennium Ecosystem Assessment published its synthesis in 2005. The most frequently reported services were provisioning services, especially medicinal plants and extracts. Despite the advances in knowledge, ecosystem services of SFSh appear to be rarely quantified, most frequently using oversimplified variable indicators. Services related to animal biodiversity, such as pollination and plague control, are poorly known. In recent years social studies of perception and valuation have increased, showing people's high valuation of SFSh. Additional studies are needed especially regarding water regulation and provision, as global warming will significantly reduce water supply in Mediterranean climates. Finally, we reflect on the advances necessary to enhance conservation, restoration and adaptation of ecosystems and their benefits to people, especially considering political, social and scientific factors. © 2023 Elsevier Ltd |
| Environmental control of the present-day sediment export along the extratropical Andes | Geomorphology | Vergara, I.; Garreaud, R.; Araneo, D.; Leyton, F. | 2023 | Agua y Extremos | 10.1016/j.geomorph.2023.108911 | https://doi.org/10.1016/j.geomorph.2023.108911 | art108911 | Vol: 441 | 0169555X | Thomson Reuters ISI (SCIE) | | English | Understanding how the environmental factors that determine erosion operate is essential to know the past and future evolution of the Earth and adequately manage natural resources. In this work, the main controlling factors of the current sediment export in the western side of the extratropical Andes (20°-55°S) are investigated using multidecadal series of specific suspended sediment yields from 42 rivers, as well as land cover, climatic, cryospheric, topographic, seismological and geological data. Through an automatic selection of Generalized Additive Models based on predictability and complexity, it was found that the combined effects of extreme runoff, glacier cover and channel steepness explain ~90 % of the spatial variability of sediment export. The runoff effect varies from positive for hyper-arid and semi-arid settings to slightly negative for moderate and wet settings, probably because of an associated increase in vegetation coupled with a recurrence and magnitude of floods that becomes greater than the time it takes for the basins to generate sediment. Cryosphere and channel steepness influences were also observed on the average suspended sediment concentration, which is less associated with water availability and more associated with erodibility and sediment availability. © 2023 Elsevier B.V. |
| A freshwater diatom perspective on the evolution of the southern westerlies for the past ∼14,000 years in southwestern Patagonia | Quaternary Science Reviews | Villacís, L.; Moreno, P.; Vilanova, I.; Henríquez, C.; Henríquez, W.; Villa-Martínez, R.; Sepúlveda-Zúñiga, E.; Maidana, N. | 2023 | Agua y Extremos | 10.1016/j.quascirev.2022.107929 | https://www.sciencedirect.com/science/article/pii/S0277379122005601 | 107929 | Vol: 301 | 02773791 | Thomson Reuters ISI (SCIE) | | English | Conflicting, even opposite interpretations on the evolution of the Southern Westerly Winds (SWW) are evident in paleoenvironmental records from southwestern Patagonia since the last ice age. These divergences call for new approaches utilizing different, ideally independent indicators of paleoenvironmental/paleoclimatic change from sensitive sites in climatically relevant locations. Here we present a multidecadally resolved diatom record from Lago Cipreses (51°S), a small closed-basin lake located in a bedrock depression along the eastern foothills of the southern Patagonian Andes. The hydrological balance evolution of this isolated lake affords a direct tie with SWW intensity in a mountainous sector where zonal wind strength and local precipitation are highly correlated. We detect cold-tolerant diatoms (small fragilarioids) between ∼14-11.9 cal. ka BP followed by a shift to planktonic assemblages (Discostella pseudostelligera, Aulacoseira spp.) under warmer Holocene conditions. Diatom assemblages indicative of stratified water-column conditions (Discostella pseudostelligera, Achnanthidium aff tepidaricola, Achnanthidium sieminskae) reached their maximum stability between ∼9.1-7.4 cal. ka BP. Stronger water-column mixing is evident by an abrupt species turnover to Aulacoseira spp. between ∼7.4-3.1 cal. ka BP, superimposed on centennial-scale alternations between assemblages since ∼6.1 cal. ka BP. Cold-tolerant diatoms resurge at ∼3.1 cal. ka BP and persist until the present. Our record offers assemblage-based evidence we interpret as sub-centennial to multimillennial scale changes in hydroclimate indicative of: (i) strong SWW influence between ∼14-11.9 cal. ka BP, (ii) a transition between ∼11.9-11.3 cal. ka BP to weak SWW influence between ∼11.3-6.5 cal. ka BP, with a SWW minimum between ∼9.1-7.4 cal. ka BP, and (iii) strong SWW influence since ∼6.5 cal. ka BP, with a Holocene SWW maximum since ∼3.1 cal. ka BP. We posit that enhanced hydroclimate variability since ∼6.1 cal. ka BP attests to the onset of Southern Annular Mode-like changes at centennial-to sub-centennial timescales. We detect a remarkably coherent and synchronous response of terrestrial and aquatic ecosystems at local scale since ∼14 cal. ka BP, highlighting the overriding importance of variations in SWW influence in terrestrial and aquatic environments at multiple timescales. © 2022 Elsevier Ltd |
| Refinement of the tephrostratigraphy straddling the northern Patagonian Andes (40–41°S): new tephra markers, reconciling different archives and ascertaining the timing of piedmont deglaciation | Journal of Quaternary Science | Alloway, B.; Pearce, N.; Moreno, P.; Villarosa, G.; Jara, I.; Henríquez, C.; Sagredo, E.; Ryan, M.; Outes, V. | 2022 | Agua y Extremos | 10.1002/jqs.3389 | https://onlinelibrary.wiley.com/doi/10.1002/jqs.3389 | 441-477 | Vol: 37 Issue: 3 | 0267-8179, 1099-1417 | Thomson Reuters ISI (SCIE) | | English | We describe the stratigraphy, age, geochemistry and correlation of tephra from west to east across the northern Patagonian Andes (c. 40–41°S) with a view to further refining the eruptive history of this region back to the onset of the Last Glacial Termination (~18 cal. ka). Eastwards across the Andes, rhyodacite to rhyolitic tephra markers of dominantly Puyehue-Cordón Caulle source are persistently recognised and provide a stratigraphic context for more numerously erupted intervening tephra of basalt to basaltic–andesite composition. Tephra from distal eruptive centres are also recognised. West of the Andean Cordillera, organic-rich cores from a small closed lake basin (Lago Pichilafquén) reveal an exceptional high-resolution record of lowland vegetation–climate change and eruptive activity spanning the last 15 400 years. Three new rhyodacite tephra (BT6-T1, -T2 and -T4) identified near the base of the Pichilafquén record, spanning 13.2 to 13.9 cal. ka bp, can be geochemically matched with correlatives in basal andic soil sequences closely overlying regolith and/or basement rock. The repetitiveness of this tephrostratigraphy across this Andean transect suggests near-synchronous tephra accretion and onset of up-building soil formation under more stable (revegetating) ground-surface conditions following rapid piedmont deglaciation on both sides of the Cordillera by at least ~14 cal. ka bp. |
| Seasonal Variations in Fjord Sediment Grain Size: A Pre‐requisite for Hydrological and Climate Reconstructions in Partially Glacierized Watersheds (Baker River, Patagonia) | Journal of Geophysical Research: Earth Surface | Amann, B.; Bertrand, S.; Alvarez‐Garreton, C.; Reid, B. | 2022 | Agua y Extremos | 10.1029/2021JF006391 | https://onlinelibrary.wiley.com/doi/10.1029/2021JF006391 | arte2021JF006391 | Vol: 127 Issue: 2 | 2169-9003, 2169-9011 | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | Fjord sediments are increasingly recognized as high-resolution archives of past hydrological and climate variability. Using them as such, however, requires a comprehensive understanding of the variables that affect their accumulation rates and properties. Here, we conduct a spatial and temporal study of sediment samples collected at the head of Martínez Channel (Chilean Patagonia, 48°S), to understand how the fjord's sediments register changes in the hydrology of Baker River, Chile's largest river in terms of mean annual discharge. We apply end-member modeling to particle-size distributions of: (a) river suspended sediments, (b) surface sediments collected along a proximal-distal transect at the fjord head, and (c) fjord sediments collected in a sequential sediment trap at 15-day resolution during two consecutive years. We then validate the use of the grain-size end members for hydrological and climate reconstructions, using a sediment core that covers the last 35 years. Results show that the river suspended sediments and fjord sediments are consistently composed of two grain-size subpopulations. The finest end member (EM1; mode 4.03 μm) reflects the meltwater contribution, which dominates in all but the winter season. The coarser end member (EM2; mode 18.7 μm) dominates in winter, when meltwater contribution is reduced, and is associated with rainfall. We show that the fluxes of EM1 and EM2 provide quantitative estimates of baseflow (r = 0.87, p < 0.001) and quickflow (r = 0.86, p < 0.001), respectively. Additionally, we propose that log (EM1/EM2) can be used to reconstruct meltwater production (r = 0.67, p < 0.001) and temperature (r = 0.81, p < 0.001) in the lower Baker River watershed. These results support the use of fjord sediments for quantitative reconstructions of hydrological and climate variability in partially glacierized watersheds. © 2022. American Geophysical Union. All Rights Reserved. |
| Prosopis L. woody growth in relation to hydrology in South America: A review | Dendrochronologia | Ambite, S.; Ferrero, M.; Piraino, S.; Badagian, J.; Muñoz, A.; Aguilera-Betti, I.; Gamazo, P.; Roig, F.; Lucas, C. | 2022 | Agua y Extremos | 10.1016/j.dendro.2022.126017 | https://linkinghub.elsevier.com/retrieve/pii/S1125786522000972 | 126017 | Vol: 76 | 11257865 | Thomson Reuters ISI (SCIE) | | English | Arboreal species of the genus Prosopis L. have played an important role in the development of tree-ring research in arid and semi-arid ecoregions of South America. Given the distribution of Prosopis across a broad precipitation gradient from 0 to 2000 mm y−1 and its unique role as a phreatophyte, the relationship between Prosopis species growth and water has been a recurring theme over the past century. We conducted a systematic review of the literature addressing Prosopis and water research in South America, and combined site coordinates with GIS data of mean annual precipitation (MAP), elevation, biome, and soil moisture from online databases to understand the spatial distribution of research to date. We compiled 40 publications from 1931 to 2022, including results from 11 species of Prosopis among four countries, on the relationship between Prosopis spp and precipitation, groundwater levels, soil humidity, among other hydrological parameters. The spatial distribution of research sites spans tropical-subtropical and temperate latitudes from 4° to 35°S, excluding regions where the genus is present in Patagonia and northeastern South America. Studies covered a broad range of elevations from 30 to 3500 m a.s.l. but was limited to 1–730 mm y−1 MAP, excluding more humid climates where Prosopis occurs. Results obtained from 32 dendrochronological studies and eight studies relating to Prosopis and hydrology, were grouped into sub-disciplines of tree-ring formation and the hydrosystem, dendroclimatology, dendrohydrology, and dendroecology. The review highlights the unique affinities of Prosopis to arid conditions, and the use of tree rings as a proxy for historical droughts and variability in water tables. Nonetheless, there are opportunities to expand the geographical-climatological extent of Prosopis growth research to humid climates, as well as to incorporate novel techniques such as stable isotopes and vessel size chronologies to understand how this genus records hydrological change throughout South America. © 2022 Elsevier GmbH |
| Comment on: “The impact of a lack of government strategies for sustainable water management and land use planning on the hydrology of water bodies: lessons learned from the disappearance of the Aculeo Lagoon in central Chile” by Valdés-Pineda et al. 2022 in Sustainability, 14(1), 413 | Regional Environmental Change | Barría, P.; Ocampo-Melgar, A.; Chadwick, C.; Galleguillos, M.; Garreaud, R.; Díaz-Vasconcellos, R.; Poblete, D.; Rubio-Álvarez, E. | 2022 | Agua y Extremos; Cambio de Uso de Suelo | 10.1007/s10113-022-01991-3 | https://link.springer.com/10.1007/s10113-022-01991-3 | 131 | Vol: 22 Issue: 4 | 1436-3798, 1436-378X | Thomson Reuters ISI (SCIE; SSCI) | | English | Valdés-Pineda et al. (Sustainability 14:413, 2022) present data for changes in climate, socio-economic, and land use and land cover (LULC) from diverse sources, concluding that the main causes for the desiccation of the Aculeo Lake were the river deviations and aquifer pumping, along with the impact of reduced precipitation. Based on that, they infer that the previous study of Barría et al. (Reg Environ Change 21:1–5, 2021a), which concluded that the impact of the decade-long drought was ten times larger than the increase of human extractions on the lake desiccation lacks scientific validity. We disagree with the conclusions from Valdés-Pineda et al. (Sustainability 14:413, 2022) and document that their article uses fragmentary information of a complex system, misinterprets of our results, and fails to present a reliable attribution methodology. We show that the hypothesis that the disappearance of Aculeo Lake was largely due to local anthropogenic uses is unsupported. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. |
| Reestatización del agua potable y resiliencia neoliberal en Uruguay | urbe. Revista Brasileira de Gestão Urbana | Bascans, M.; Nicolas-Artero, C.; Gautreau, P.; Santos, C. | 2022 | Agua y Extremos | 10.1590/2175-3369.014.e20210133 | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2175-33692022000100212&tlng=es | e20210133 | Vol: 14 | 2175-3369 | Thomson Reuters ISI (ESCI) | All Open Access; Gold Open Access | Spanish | Resumen El artículo discute sobre la neoliberalización de la naturaleza a partir del estudio de la reestatización de los servicios de distribución del agua potable y saneamiento en Uruguay durante el gobierno progresista del Frente Amplio. Se propone el concepto de “resiliencia neoliberal” para entender la reproducción de una lógica neoliberal en la gestión de estos servicios a pesar del reconocimiento del derecho humano al agua en la Constitución del país. A partir de una metodología cualitativa y cuantitativa, se reconstruye el proceso de privatización de los servicios hídricos y sus repercusiones sociales. Se identifican cuatro procesos que frenan la vuelta a servicios públicos y estatales: la permanencia de concesiones con capitales privados, la fragilización del sistema de subsidios cruzados, la desmovilización de la oposición y la inserción en un modelo de desarrollo económico neoliberal.
,
Abstract The article discusses the neoliberalisation of nature based on the study of the re-establishment of drinking water and sanitation services in Uruguay during the progressive government of the Frente Amplio. The concept of neoliberal resilience is proposed to understand the reproduction of a neoliberal logic in the management of these services despite the recognition of the human right to water in the Constitution. Using a qualitative and quantitative methodology, we reconstruct the process of privatisation of drinking water services and its social repercussions. Four processes are identified that slow down the return to public and state services: the permanence of concessions with private capital, the weakening of the system of cross-subsidies, the demobilisation of the opposition and the insertion of a neoliberal economic development model.
,
Resumo O artigo discute a neoliberalização da natureza com base no estudo do restabelecimento dos serviços de distribuição de água potável e saneamento no Uruguai durante o governo progressista da Frente Ampla. O conceito de resiliência neoliberal é proposto para compreender a reprodução de uma lógica neoliberal na gestão destes serviços, apesar do reconhecimento do direito humano à água na Constituição. Utilizando uma metodologia qualitativa e quantitativa, reconstruímos o processo de privatização dos serviços de água potável e suas repercussões sociais. São identificados quatro processos que abrandam o regresso aos serviços públicos e estatais: a permanência das concessões com capital privado, o enfraquecimento do sistema de subsídios cruzados, a desmobilização da oposição e a inserção num modelo de desenvolvimento econômico neoliberal. |
| Global wood anatomical perspective on the onset of the Late Antique Little Ice Age (LALIA) in the mid-6th century CE | Science Bulletin | Büntgen, U.; Crivellaro, A.; Arseneault, D.; Baillie, M.; Barclay, D.; Bernabei, M.; Bontadi, J.; Boswijk, G.; Brown, D.; Christie, D.; Churakova, O.; Cook, E.; D’Arrigo, R.; Davi, N.; Esper, J.; Fonti, P.; Greaves, C.; Hantemirov, R.; Hughes, M.; Kirdyanov, A.; Krusic, P.; Le Quesne, C.; Ljungqvist... | 2022 | Agua y Extremos | 10.1016/j.scib.2022.10.019 | https://linkinghub.elsevier.com/retrieve/pii/S2095927322004790 | 2336-2344 | Vol: 67 Issue: 22 | 2095-9273 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | Linked to major volcanic eruptions around 536 and 540 CE, the onset of the Late Antique Little Ice Age has been described as the coldest period of the past two millennia. The exact timing and spatial extent of this exceptional cold phase are, however, still under debate because of the limited resolution and geographical distribution of the available proxy archives. Here, we use 106 wood anatomical thin sections from 23 forest sites and 20 tree species in both hemispheres to search for cell-level fingerprints of ephemeral summer cooling between 530 and 550 CE. After cross-dating and double-staining, we identified 89 Blue Rings (lack of cell wall lignification), nine Frost Rings (cell deformation and collapse), and 93 Light Rings (reduced cell wall thickening) in the Northern Hemisphere. Our network reveals evidence for the strongest temperature depression between mid-July and early-August 536 CE across North America and Eurasia, whereas more localised cold spells occurred in the summers of 532, 540–43, and 548 CE. The lack of anatomical signatures in the austral trees suggests limited incursion of stratospheric volcanic aerosol into the Southern Hemisphere extra-tropics, that any forcing was mitigated by atmosphere-ocean dynamical responses and/or concentrated outside the growing season, or a combination of factors. Our findings demonstrate the advantage of wood anatomical investigations over traditional dendrochronological measurements, provide a benchmark for Earth system models, support cross-disciplinary studies into the entanglements of climate and history, and question the relevance of global climate averages. © 2022 Science China Press |
| Worldwide Signature of the 2022 Tonga Volcanic Tsunami | Geophysical Research Letters | Carvajal, M.; Sepúlveda, I.; Gubler, A.; Garreaud, R. | 2022 | Agua y Extremos | 10.1029/2022GL098153 | https://onlinelibrary.wiley.com/doi/10.1029/2022GL098153 | arte2022GL098153 | Vol: 49 Issue: 6 | 0094-8276, 1944-8007 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | The eruption of the Hunga Tonga-Hunga Ha'apai Volcano in January 2022 in the southwest Pacific islands of Tonga triggered a tsunami that was detected beyond the Pacific basin. Here we show its spatiotemporal signature as revealed by hundreds of publicly available coastal tide gauge records from around the world. The Tonga tsunami was characterized by a uniformly small leading wave that arrived earlier than theoretically expected for a tsunami wave freely propagating away from the volcano. In contrast, the largest waves, of up to +3 m high, were concentrated in the Pacific and their timing agrees well with tsunami propagation times from the volcano. While the leading waves were caused by a previously reported fast-moving atmospheric pressure pulse generated in the volcanic explosion, the large waves observed later in the Pacific were likely originated in the vicinity of the volcano although its generation mechanism(s) cannot be identified by the tide gauge data alone. © 2022. American Geophysical Union. All Rights Reserved. |
| High ENSO sensitivity in tree rings from a northern population of Polylepis tarapacana in the Peruvian Andes | Dendrochronologia | Crispín-DelaCruz, D.; Morales, M.; Andreu-Hayles, L.; Christie, D.; Guerra, A.; Requena-Rojas, E. | 2022 | Agua y Extremos | 10.1016/j.dendro.2021.125902 | https://linkinghub.elsevier.com/retrieve/pii/S1125786521000989 | 125902 | Vol: 71 | 1125-7865 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Polylepis tarapacana is the highest-elevation tree species worldwide growing between 4000 and 5000 m a.s.l. along the South American Altiplano. P. tarapacana is adapted to live in harsh conditions and has been widely used for drought and precipitation tree-ring based reconstructions. Here, we present a 400-year tree-ring width (TRW) chronology located in southern Peru (17ºS; 69ºW) at the northernmost limit of P. tarapacana tree species distribution. The objectives of this study are to assess tree growth sensitivity of a northern P. tarapacana population to (1) precipitation, temperature and El Niño Southern Oscillation (ENSO) variability; (2) to compare its growth variability and ENSO sensitivity with southern P. tarapacana forests. Our results showed that this TRW record is highly sensitive to the prior summer season (Nov-Jan) precipitation (i.e. positive correlation) when the South American Summer Monsoon (SASM) reaches its maximum intensity in this region. We also found a positive relationship with current year temperature that suggests that radial growth may be enhanced by warm, less cloudy, conditions during the year of formation. A strong positive relationship was found between el Niño 3.4 and tree growth variability during the current growing season, but negative during the previous growth period. Growth variability in our northern study site was in agreement with other populations that represent almost the full range of P. tarapacana latitudinal distribution (~ 18ºS to 23ºS). Towards the south of the P. tarapacana TRW network there was a decrease in the strength of the agreement of growth variability with our site,with the exception of higher correlation with the two southeastern sites. Similarly, the TRW chronologies recorded higher sensitivity to ENSO influences in the north and southeastern locations, which are wetter, than the drier southwestern sites. These patterns hold for the entire period, as well as for periods of high and low ENSO activity. Overall, P. tarapacana tree growth at the north of its distribution is mostly influenced by prior year moisture availability and current year temperature that are linked to large-scale climate patterns such as the SASM and ENSO, respectively. |
| Running a scientific conference during pandemic times | Bulletin of the American Meteorological Society | Garreaud, R.; Ralph, M.; Wilson, A.; Ramos, A.; Eiras-Barca, J.; Steen-Larsen, H.; Rutz, J.; Albano, C.; Tilinina, N.; Warner, M.; Viale, M.; Rondanelli, R.; McPhee, J.; Valenzuela, R.; Gorodetskaya, I. | 2022 | Agua y Extremos; Zonas Costeras | 10.1175/BAMS-D-22-0023.1 | https://journals.ametsoc.org/view/journals/bams/aop/BAMS-D-22-0023.1/BAMS-D-22-0023.1.xml | E1650-E1657 | Vol: 103 | 0003-0007, 1520-0477 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | |
| A Cross‐Cutting Approach for Relating Anthropocene, Environmental Injustice and Sacrifice Zones | Earth's Future | Gayo, E.; Muñoz, A.; Maldonado, A.; Lavergne, C.; Francois, J.; Rodríguez, D.; Klock‐Barría, K.; Sheppard, P.; Aguilera‐Betti, I.; Alonso‐Hernández, C.; Mena‐Carrasco, M.; Urquiza, A.; Gallardo, L. | 2022 | Agua y Extremos; Ciudades Resilientes | 10.1029/2021EF002217 | https://onlinelibrary.wiley.com/doi/10.1029/2021EF002217 | arte2021EF002217 | Vol: 10 Issue: 4 | 2328-4277, 2328-4277 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The Anthropocene is an uneven phenomenon. Accelerated shifts in the functioning of the Earth System are mainly driven by the production and consumption of wealthy economies. Social, environmental and health costs of such industrialization, however, bear on low-income communities inhabiting severely degraded territories by polluting activities (i.e., sacrifice zones). How global, national and local socio-economic and governance processes have interacted in perpetuating socio-environmental inequalities in these territories has been rarely explored. Here, we develop an historical quantitative approach integrating a novel chemostratigraphic record, data on policy making, and socio-economic trends to evaluate the feedback relationship between environmental injustice and Anthropocene in sacrifice zones. We specifically outline a case study for the Puchuncaví valley -one of the most emblematic sacrifice zones from Chile-. We verify an ever-growing burden of heavy metals and metalloids over the past five decades paced by the staggering expansion of local industrial activities, which has ultimately been spurred by national and transnational market forces. Local poverty levels have declined concomitantly, but this path toward social equality is marginal as costs of pollution have grown through time. Indeed, national and international pollution control actions appear insufficient in mitigating the cumulative impact brought by highly toxic elements. Thus, our sub-decadal reconstruction for pollution trends over the past 136 years from a sediment record, emerges as a science-based tool for informing the discussion on Anthropocene governance. Furthermore, it helps to advance in the assessment of environmental inequality in societal models that prioritize economic growth to the detriment of socio-environmental security. © 2022 The Authors. Earth's Future published by Wiley Periodicals LLC on behalf of American Geophysical Union. |
| A coupled modeling approach to assess the effect of forest policies in water provision: A biophysical evaluation of a drought-prone rural catchment in south-central Chile | Science of The Total Environment | Gimeno, F.; Galleguillos, M.; Manuschevich, D.; Zambrano-Bigiarini, M. | 2022 | Agua y Extremos; Cambio de Uso de Suelo | 10.1016/j.scitotenv.2022.154608 | https://linkinghub.elsevier.com/retrieve/pii/S0048969722017016 | 154608 | Vol: 830 | 0048-9697 | Thomson Reuters ISI (SCIE) | | English | The effect of different forest conservation policies on water provision has been poorly investigated due to a lack of an integrative methodological framework that enables its quantification. We developed a method for assessing the effects of forest conservation policies on water provision for rural inhabitants, based on a land-use model coupled with an eco-hydrological model. We used as a case study the Lumaco catchment, Chile, a territory dominated by native forests (NF) and non-native tree farms, with an extended dry period where nearly 12,600 people of rural communities get drinking water through water trucks. We analyzed three land-use policy scenarios: i) a baseline scenario based on historical land-cover maps; ii) a NF Recovery and Protection (NFRP) scenario, based on an earlier implementation of the first NF Recovery and Forestry Development bill; and iii) a Pristine (PR) scenario, based on potential vegetation belts; the latter two based on Dyna CLUE, and simulated between 1990 and 2015. Impacts on water provision from each scenario were computed with SWAT. The NFRP scenario resulted in an increase of 6974 ha of NF regarding the baseline situation, and the PR scenario showed an increase of 26,939 ha of NF. Despite large differences in NF areas, slight increases in inflows (Q) were found between the NFRP and the PR scenarios, with relative differences with respect to the baseline of 0.3% and 2.5% for NFRP and PR, respectively. Notwithstanding, these small differences in the NFRP scenario, they become larger if we analyze the cumulative values during the dry season only (December, January, and February), where they reach 1.1% in a normal year and 3.1% in a dry year. Flows increases were transformed into water truck costs resulting in up to 441,876 USD (monthly) of fiscal spending that could be avoided during a dry period. © 2022 Elsevier B.V. |
| Drivers of Flammability of Eucalyptus globulus Labill Leaves: Terpenes, Essential Oils, and Moisture Content | Forests | Guerrero, F.; Carmona, C.; Hernández, C.; Toledo, M.; Arriagada, A.; Espinoza, L.; Bergmann, J.; Taborga, L.; Yañez, K.; Carrasco, Y.; Muñoz, A. | 2022 | Agua y Extremos | 10.3390/f13060908 | https://www.mdpi.com/1999-4907/13/6/908 | 908 | Vol: 13 Issue: 6 | 1999-4907 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Mediterranean climate regions have become more vulnerable to fire due to the extreme weather conditions and numerous Eucalyptus globulus plantation areas. The aim of this study is to analyze the fire hazard related to E. globulus in a forest fire scenario, based on the contrast of thermochemical parameters and their relationship with chemical properties, considering the predominant exotic forest species (E. globulus, Pinus radiata, Acacia dealbata, and Acacia melanoxylon) present in the Valparaiso region, Chile. The results revealed that although all of the studied species were highly flammable, E. globulus was extremely flammable, as its leaves contain high concentrations of essential oils, monoterpenes, and sesquiterpenes, which can generate a flammable atmosphere due to their low flashpoint and the strong negative influence shown between the essential oils, volatile terpenes, and limonene concentration. Moreover, the heat of combustion of E. globulus was positively correlated with its high essential oil contents. Finally, all of the studied species had low flashpoints and high heating values; therefore, they are predisposed to ignite in the presence of a heat source, releasing high amounts of energy during combustion, which contributes to the risk of the formation and spread of canopy fires among these tree formations. |
| Hydrologic Sensitivities and ENSO Variability Across Hydrological Regimes in Central Chile (28°–41°S) | Water Resources Research | Hernandez, D.; Mendoza, P.; Boisier, J.; Ricchetti, F. | 2022 | Agua y Extremos | 10.1029/2021WR031860 | https://onlinelibrary.wiley.com/doi/10.1029/2021WR031860 | arte2021WR031860 | Vol: 58 Issue: 9 | 0043-1397, 1944-7973 | Thomson Reuters ISI (SCIE) | | English | There is strong evidence of El Niño-Southern Oscillation (ENSO) teleconnections in the South Pacific and related impacts on the precipitation regime in Chile; nonetheless, many aspects of the hydrological propagation and temperature responses to ENSO remain unclear in this region. We examine fluctuations across 59 near-natural catchments in central Chile (28°–41°S) under contrasting ENSO phases during the period 1981–2019. Our results show statistically significant ENSO-related hydroclimatic anomalies in almost all watersheds analyzed, which confirms the major influence of ENSO within this domain. By comparing El Niño phases against La Niña, we observe generally wetter conditions, warmer winters, cooler late springs, lower (higher) runoff ratios in snowmelt-driven (rainfall-driven) basins, and longer storm durations while storm frequencies (i.e., number of events of consecutive days with precipitation) are preserved. Additionally, low (high) elevation catchments are related to positive (negative) streamflow sensitivities to winter temperature, which increase in magnitude with the evaporative index; besides, catchments with sharp warm-and-dry conditions yield largely negative sensitivities to late spring temperature. Further, positive streamflow anomalies in rainfall-driven catchments are explained by temperature and precipitation ENSO-related amplitudes (El Niño minus La Niña) that separately favor streamflow; however, in mixed regimes and snowmelt-driven basins these results are spatially scattered. Hence, this study supports that meteorological, hydrological, and physiographic attributes modulate the translation of climate variability into river hydrology. The results presented here unravel the joint effects of precipitation and seasonal temperature fluctuations through different hydrological regimes, across a region that encloses populated cities and water-intensive activities. © 2022. American Geophysical Union. All Rights Reserved. |
| The challenge of unprecedented floods and droughts in risk management | Nature | Kreibich, H.; Van Loon, A.; Schröter, K.; Ward, P.; Mazzoleni, M.; Sairam, N.; Abeshu, G.; Agafonova, S.; AghaKouchak, A.; Aksoy, H.; Alvarez-Garreton, C.; Aznar, B.; Balkhi, L.; Barendrecht, M.; Biancamaria, S.; Bos-Burgering, L.; Bradley, C.; Budiyono, Y.; Buytaert, W.; Capewell, L.; Carlson, H.; ... | 2022 | Agua y Extremos | 10.1038/s41586-022-04917-5 | https://www.nature.com/articles/s41586-022-04917-5 | 80-86 | Vol: 608 Issue: 7921 | 0028-0836, 1476-4687 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | Abstract
Risk management has reduced vulnerability to floods and droughts globally
1,2
, yet their impacts are still increasing
3
. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data
4,5
. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change
3
. |
| Cross-continental hydroclimate proxies: Tree-rings in Central Chile reconstruct historical streamflow in Southeastern South American rivers | Progress in Physical Geography: Earth and Environment | Lucas, C.; Aguilera-Betti, I.; Muñoz, A.; Puchi, P.; Sapriza, G.; Profumo, L.; Maxwell, R.; Venegas-González, A. | 2022 | Agua y Extremos | 10.1177/03091333211067466 | http://journals.sagepub.com/doi/10.1177/03091333211067466 | 030913332110674 | Vol: 46 | 0309-1333 | Thomson Reuters ISI (SCIE) | | English | Regional teleconnections permit cross-continental modeling of hydroclimate throughout the world. Tree-rings are a good hydroclimatic proxy used to reconstruct drought and streamflow in regions that respond to common global forcings. We used a multi-species dataset of 32 tree-ring width chronologies from Chile and Uruguay as a climate proxy to infer annual streamflow (Q) variability in the Negro River basin, a grassland-dominated watershed of lowland Southeastern South America. A positive linear correlation between tree-ring chronologies from Central Chile and annual Negro River instrumental streamflow from 1957 to 2012 indicated a cross-continental teleconnection between hydroclimate variability in Central Chile and Northeastern Uruguay. This relationship was mediated in part by the El Niño Southern Oscillation (ENSO), whereby the El Nino 3.4 Index was positively correlated with regional rainfall, annual tree growth, and Q anomalies. Despite the proximity of Uruguayan tree-ring chronologies to Negro River hydrometric stations, the Chilean tree-ring chronologies best predicted annual streamflow. Thus, using tree-ring data from four long-term moisture-sensitive chronologies of the species Cryptocarya alba in Central Chile (32–34°S), we present the first streamflow reconstruction (1890–2009) in the lower La Plata Basin. The reconstruction supports regional evidence for increasing frequency of extreme flood years over the past century in Uruguay. We demonstrate how climate teleconnections that mediate local hydroclimate variability permit the cross-continental reconstruction of streamflow, filling a major geographical gap in historical proxies for flooding and drought in grassland biomes of the southern hemisphere. |
| Direct effects of tephra fallout from the Puyehue–Cordón Caulle Volcanic Complex on Nothofagus pumilio ring widths in northern Patagonia | Dendrochronologia | Montiel, M.; González, M.; Christie, D.; Muñoz, A.; Crisafulli, C. | 2022 | Agua y Extremos; Cambio de Uso de Suelo | 10.1016/j.dendro.2022.125998 | https://linkinghub.elsevier.com/retrieve/pii/S1125786522000789 | 125998 | Vol: 75 | 11257865 | Thomson Reuters ISI (SCIE) | | English | We evaluated the radial growth response of adult Nothofagus pumilio (Poepp. et Endl) Krasser trees affected by tephra deposition following historical volcanic eruptions of the Puyehue–Cordón Caulle Volcanic Complex (PCCVC) in northern Patagonia. Standard tree–ring width chronologies were developed for trees from two sites that were affected by up to 55 cm of tephra during the 2011 eruption, which allowed us to detect the general tree–growth response to eruptions VEI ≥ 3 and VEI ≤ 2. The tree growth trend satisfactorily followed the mean temperature record (r = 0.42); however, the analysis of studentized residuals identified outliers (≥ ± 2 SD) directly related to the volcanic eruptions of the years 1921–1922 and 2011 and the respective post–eruption years, while for the 1960 eruption and following year, they largely exceeded the mean value of the residuals. The large amount of tephra deposited during the 1921–22 and 2011 eruptions caused physical damage to the tree canopy leading to the appearance of white rings and to locally absent rings. The rate of change in radial growth of trees during these eruptions presented significant declines in relation to the growth of five years before the eruption and to the following year. The low amount of tephra deposited during the 1960 eruption did not cause damage to the stands and trees increased their radial growth. In general, trees that had reduced radial growth experienced a remarkable recovery starting in the second or third post–eruption year. The amount of tephra deposited and the time of year of the volcanic eruptions had an important influence on tree rings. Some ecophysiological causes that could explain the growth responses of N. pumilio to tephra fall are discussed herein. Our study may provide useful insights to clarify the uncertain characteristics of some eruptions in the past or to detect the occurrence of large, undocumented volcanic eruptions throughout the Andes. © 2022 Elsevier GmbH |
| Glacier and terrestrial ecosystem evolution in the Chilotan archipelago sector of northwestern Patagonia since the Last Glacial Termination | Earth-Science Reviews | Moreno, P.; Fercovic, E.; Soteres, R.; Ugalde, P.; Sagredo, E.; Villa-Martínez, R. | 2022 | Agua y Extremos | 10.1016/j.earscirev.2022.104240 | https://linkinghub.elsevier.com/retrieve/pii/S0012825222003245 | 104240 | Vol: 235 | 0012-8252 | Thomson Reuters ISI (SCIE) | | English | We examine the glacier, terrestrial ecosystem, and climate evolution since the Last Glacial Termination (T1) based on glacial sediments/landform assemblages and palynological data from the Chilotan archipelago (41°30′S-43°30′S), northwestern Patagonia. Deglacial warming drove recession of the Golfo Corcovado glacier lobe from the Last Glacial Maximum moraines in the interior of Isla Grande de Chiloé (IGC) before ∼17.8 ka, along with a rapid and irreversible trend toward arboreal dominance. Subsequent glacier stabilization led to deposition of the innermost moraines in eastern IGC and adjacent islands sometime between ∼17.5–16.9 ka, followed by an acceleration in glacial retreat that vacated the Chilotan Interior Sea in ∼200 years or less. Early successional cold-tolerant shade-intolerant trees prevailed during the initial stages of T1, followed by temperate rainforests dominated by thermophilous shade-tolerant species between ∼15–14.5 ka. A mixed forest with cold-tolerant hygrophilous conifers established between ∼14.5–12.6 ka, implying cooler climate and stronger Southern Westerly Wind (SWW) influence during the Antarctic Cold Reversal. Stand-replacing fires favored early successional shade-intolerant trees, shrubs, and herbs between ∼12.6–10.8 ka in response to milder temperatures and weaker SWW during Younger Dryas time. The early Holocene (∼10.8–7.5 ka) features a maximum in shade-intolerant thermophilous trees, absence of conifers, and peak fire activity, signaling a warm/dry interval with minimum SWW influence. Cooler/wetter conditions have prevailed over the last ∼7500 years driven by strong SWW influence. We conclude that Patagonian glaciers and terrestrial ecosystems responded simultaneously to climate changes at regional, hemispheric, and global scales multiple times since T1. We adhere to the concept that millennial-scale variations in the SWW linked the response of the hydro- bio and cryosphere across the southern mid- and high southern latitudes, and were teleconnected with northern hemisphere events through the atmospheric concentration of greenhouse gases, latitudinal shifts in the Intertropical convergence zone, and deep ocean circulation. © 2022 Elsevier B.V. |
| Examining the potential of Austrocedrus chilensis tree rings as indicators of past late-spring frost events in central Chile | Dendrochronologia | Muñoz-Salazar, T.; LeQuesne, C.; Rozas, V.; Christie, D.; Rojas-Badilla, M. | 2022 | Agua y Extremos | 10.1016/j.dendro.2022.125962 | https://linkinghub.elsevier.com/retrieve/pii/S112578652200042X | 125962 | Vol: 74 | 11257865 | Thomson Reuters ISI (SCIE) | | English | Austrocedrus chilensis is a South American conifer broadly distributed across the subtropical and extratropical Andes that is widely utilized in tree-ring studies. This species has clear annual growth rings that are sensitive to the moisture supply and has been extensively used to reconstruct the past hydroclimate during the last millennium. Despite a great number of dendrochronological studies based on tree-ring width, little is known about the potential of the species to record intra-annual anomalies and particularly frost rings. In this study, the main traits of A. chilensis frost rings were studied and the ability of this endemic Cupressaceae to record spring frosts at five sites across a latitudinal gradient between the Mediterranean and Northern Patagonian Andes was evaluated. The average ages of trees in the study sites varied from 168 to 343 years, with minimum and maximum ages of 33 and 919 years. The results indicated that 85% of the frost rings occurred at the beginning of the earlywood and 15% showed a mid intra-ring position. Regarding the portion of the ring circumference affected by frost damage in cross sections, 59% of the injuries partially affected the entire ring, 30% affected the complete ring circumference, and 11% resulted in a ring fracture. Freezing temperatures that generated frost rings in A. chilensis from the upper treeline coincided with events below 0 °C recorded in the agricultural Central Valley of Chile. We estimated the potential time window of the formation of A. chilensis frost rings over a two and a half month period from the end of September to mid-November (early spring). Our results indicated that tree age was a determinant factor affecting the ability of trees to record frost rings. The maximum frequency of frost rings occurred at 12 years and the maximum age at which 95% of the total frost injuries occurred within our network was about 120 years. Both the exceptional longevity and the excellent state of preservation of relict wood demonstrates that A. chilensis frost rings provide a reliable proxy for monitoring and reconstructing late-spring frost events in central Chile. © 2022 Elsevier GmbH |
| Using Commercial Aircraft Meteorological Data to Assess the Heat Budget of the Convective Boundary Layer Over the Santiago Valley in Central Chile | Boundary-Layer Meteorology | MuñozR, R.; Whiteman, C.; Garreaud, R.; Rutllant, J.; Hidalgo, J. | 2022 | Agua y Extremos | 10.1007/s10546-021-00685-3 | https://link.springer.com/10.1007/s10546-021-00685-3 | 295-319 | Vol: 183 Issue: 2 | 0006-8314, 1573-1472 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | The World Meteorological Organization Aircraft Meteorological Data Relay (AMDAR) programme refers to meteorological data gathered by commercial aircraft and made available to weather services. It has become a major source of upper-air observations whose assimilation into global models has greatly improved their performance. Near busy airports, AMDAR data generate semi-continuous vertical profiles of temperature and winds, which have been utilized to produce climatologies of atmospheric-boundary-layer (ABL) heights and general characterizations of specific cases. We analyze 2017–2019 AMDAR data for Santiago airport, located in the centre of a
$$40\times 100$$
40
×
100
km
$$^2$$
2
subtropical semi-arid valley in central Chile, at the foothills of the Andes. Profiles derived from AMDAR data are characterized and validated against occasional radiosondes launched in the valley and compared with routine operational radiosondes and with reanalysis data. The cold-season climatology of AMDAR temperatures reveals a deep nocturnal inversion reaching up to 700 m above ground level (a.g.l.) and daytime warming extending up to 1000 m a.g.l. Convective-boundary-layer (CBL) heights are estimated based on AMDAR profiles and the daytime heat budget of the CBL is assessed. The CBL warming variability is well explained by the surface sensible heat flux estimated with sonic anemometer measurements at one site, provided advection of the cool coastal ABL existing to the west is included. However, the CBL warming accounts for just half of the mean daytime warming of the lower troposphere, suggesting that rather intense climatological diurnal subsidence affects the dynamics of the daytime valley ABL. Possible sources of this subsidence are discussed. |
| Ensuring access to water in an emergency context: Towards an overexploitation and contamination of water resources? | Social & Legal Studies | Nicolas-Artero, C. | 2022 | Agua y Extremos | 10.1177/09646639211031626 | http://journals.sagepub.com/doi/10.1177/09646639211031626 | 459-476 | Vol: 31 Issue: 3 | 1461-7390 | Thomson Reuters ISI (SSCI) | | English | This article shows how geo-legal devices created to deal with environmental crisis situations make access to drinking water precarious and contribute to the overexploitation and contamination of water resources. It relies on qualitative methods (interviews, observations, archive work) to identify and analyse two geo-legal devices applied in the case study of the Elqui Valley in Chile. The first device, generated by the Declaration of Water Scarcity, allows private sanitation companies to concentrate water rights and extend their supply network, thus producing an overexploitation of water resources. In the context of mining pollution, the second device is structured around the implementation of the Rural Drinking Water Programme and the distribution of water by tankers, which has made access to drinking water more precarious for the population and does nothing to prevent pollution. |
| Modes of access to water for domestic use in rural Chile: a typological proposal | Water Policy | Nicolas-Artero, C.; Blanco, G.; Bopp, C.; Carrasco, N. | 2022 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | 10.2166/wp.2022.026 | https://iwaponline.com/wp/article/24/7/1179/89257/Modes-of-access-to-water-for-domestic-use-in-rural | 1179-1194 | Vol: 24 Issue: 7 | 1366-7017, 1996-9759 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | A typology is proposed regarding the modes of access to water for the rural population in Chile as well as four explanatory dimensions of its heterogeneity. The typology emerges from a systematic review of the literature and an analysis of quantitative data based on rural water organizations' databases. The modes of access are defined by the following five criteria: their socio-technical system, their type of management, their level of spatial action, the source of their financing, and the type of technical assistance they received. The findings dispute the systemic vision of access to water in rural areas and invite us to consider the structural heterogeneity in regulations and public policies to guarantee the human right to water. |
| Chlorine-36 Surface Exposure Dating of Late Holocene Moraines and Glacial Mass Balance Modeling, Monte Sierra Nevada, South-Central Chilean Andes (38°S) | Frontiers in Earth Science | Price, B.; Stansell, N.; Fernández, A.; Licciardi, J.; Lesnek, A.; Muñoz, A.; Sorensen, M.; Jaque Castillo, E.; Shutkin, T.; Ciocca, I.; Galilea, I. | 2022 | Agua y Extremos | 10.3389/feart.2022.848652 | https://www.frontiersin.org/articles/10.3389/feart.2022.848652/full | 848652 | Vol: 10 | 2296-6463 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The development of robust chronologies of Neoglaciation from individual glaciers throughout the high-altitude Andes can provide fundamental knowledge of influences such as regional temperature and precipitation variability, and aid in predicting future changes in the Andean climate system. However, records of Late Holocene glaciation from the Central Chilean Andes are sparse, and often poorly constrained. Here, we present
36
Cl surface exposure ages, dendrochronologic constraints, and glacial mass balance modeling simulations of Late Holocene glacier fluctuations in the Central-South Chilean Andes. A series of concentric moraine ridges were identified on Monte Sierra Nevada (38°S), where exposure dating of basaltic boulders was used to establish a chronology of ice recession. We infer that moraine abandonment of the most distal ridge in the valley commenced by ∼4.2 ka, and was followed by glacier margin retreat to an up-valley position. Exposure ages of the oldest Late Holocene boulders (∼2.5–0.8 ka) along the marginal extents of the moraine complex indicate fluctuations of the glacier terminus prior to ∼0.65 ka. A final expansion of the ice margin reoccupied the position of the 4.2 ka moraine, with abatement from the outermost composite moraine occurring by ∼0.70 ka, as constrained by tree-ring data from live
Araucaria araucana
trees. Finally, a series of nested moraines dating to ∼0.45–0.30 ka, formed from a pulsed ice recession during the latest Holocene when the lower reaches of the glacial snout was most likely debris mantled. A distributed temperature index model combined with a glacier flow model was used to quantify an envelope of possible climatic conditions of Late Holocene glaciation. The glacial modeling results suggest conditions were ∼1.5°C colder and 20% wetter during peak Neoglaciation relative to modern conditions. These records also suggest a near-coeval record of Late Holocene climate variability between the middle and high southern latitudes. Furthermore, this study presents some of the youngest
36
Cl exposure ages reported for moraines in the Andes, further supporting this method as a valuable geochronologic tool for assessing Late Holocene landscape development. |
| Coping Strategies and Tactics to Deal With Social Vulnerability in the Flood Disaster of March 25, 2015, in Chañaral and Diego de Almagro, Chile | Frontiers in Climate | Pérez Tello, S.; Aldunce Ide, P.; Flores-Haverbeck, F.; Mena Maldonado, D.; Castro Correa, C.; Wyndham Vásquez, K. | 2022 | Agua y Extremos | 10.3389/fclim.2022.763413 | https://doi.org/10.3389/fclim.2022.763413 | art: 763413 | Vol: 4 | 2624-9553 | Thomson Reuters ISI (ESCI) | All Open Access; Gold Open Access | English | A socio-natural disaster event exacerbates pre-existing socio-economic crises and disrupts the life projects of the people affected, generating the deployment of strategic or tactical actions to deal with it. When societies have populations living in conditions of social vulnerability prior to disasters, such actions are more complex and difficult to manage. On March 25, 2015 (25M), the inhabitants of the towns of Chañaral and Diego de Almagro, in the Atacama Region of Chile, were faced with a flood that produced a crisis of great magnitude. This qualitative research describes the actions the inhabitants used to reduce social vulnerability, before, during and after the emergency. These actions were analyzed to describe the extent of planning, meanings, resources and structures of opportunities present in the actions. Content analysis was carried out on semi-structured interviews with 38 affected people, selected using intentional sampling technique together with snowball sampling. Subjective resources were identified: sense of family, solidarity, autonomy and restitution of rights. The superimposed mobilization of these resources resulted in a complex situation of resilience. It is concluded that the way of learning actions includes family and cultural habits, daily learning and previous experiences, and imitation, among others. Recommendations are made to be considered for the reduction of risks of socio-natural disasters. Specifically, policies that include educational strategies that are based on theways of acting shown by the communities. Copyright © 2022 Pérez Tello, Aldunce Ide, Flores-Haverbeck, Mena Maldonado, Castro Correa and Wyndham Vásquez. |
| Hydroclimate and ENSO Variability Recorded by Oxygen Isotopes From Tree Rings in the South American Altiplano | Geophysical Research Letters | Rodriguez‐Caton, M.; Andreu‐Hayles, L.; Daux, V.; Vuille, M.; Varuolo‐Clarke, A.; Oelkers, R.; Christie, D.; D’Arrigo, R.; Morales, M.; Palat Rao, M.; Srur, A.; Vimeux, F.; Villalba, R. | 2022 | Agua y Extremos | 10.1029/2021GL095883 | https://onlinelibrary.wiley.com/doi/10.1029/2021GL095883 | arte2021GL095883 | Vol: 49 Issue: 4 | 0094-8276, 1944-8007 | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | Hydroclimate variability in tropical South America is strongly regulated by the South American Summer Monsoon (SASM). However, past precipitation changes are poorly constrained due to limited observations and high-resolution paleoproxies. We found that summer precipitation and the El Niño-Southern Oscillation (ENSO) variability are well registered in tree-ring stable oxygen isotopes (δ18OTR) of Polylepis tarapacana in the Chilean and Bolivian Altiplano in the Central Andes (18–22°S, ∼4,500 m a.s.l.) with the northern forests having the strongest climate signal. More enriched δ18OTR values were found at the southern sites likely due to the increasing aridity toward the southwest of the Altiplano. The climate signal of P. tarapacana δ18OTR is the combined result of moisture transported from the Amazon Basin, modulated by the SASM, ENSO, and local evaporation, and emerges as a novel tree-ring climate proxy for the southern tropical Andes. © 2022. The Authors. |
| Are Citizens Ready for Active Climate Engagement or Stuck in a Game of Blame? Local Perceptions of Climate Action and Citizen Participation in Chilean Patagonia | Sustainability | Sapiains, R.; Azócar, G.; Moraga, P.; Valenzuela, C.; Aldunce, P.; Cornejo, C.; Rojas, M.; Pulgar, A.; Medina, L.; Bozkurt, D. | 2022 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | 10.3390/su141912034 | https://www.mdpi.com/2071-1050/14/19/12034 | 12034 | Vol: 14 Issue: 19 | 2071-1050 | Thomson Reuters ISI (SCIE; SSCI) | All Open Access; Gold Open Access | English | Deep structural transformations aimed at strengthening climate action and community participation are occurring in Chile, especially after the social unrest of October 2019. The ongoing political crisis has even generated the unprecedented possibility of writing a new constitution through an entirely democratic process. This article explores to what extent these structural transformations are also associated with cognitive and relational changes in the population, especially in terms of community participation. An online survey (n = 1.117) was applied to people over 18 years old in Punta Arenas in November 2020. This is the southernmost city of the American continent, one of the areas most affected by climate change, highly isolated from the rest of the country, and with a strong regional ecological identity. Results show that climate change is perceived as the main environmental problem affecting the city, with multiple negative consequences, but also with some potentially positive impacts. At the same time, environmental and constitutional expectations suggest the state of the environment is deemed to be critical for the future of the city. However, a traditional top-down understanding of community participation still prevails as most participants perceive the citizens’ role in dealing with environmental issues as limited to individual, passive, and reactive actions, or reduced to being responsible consumers. These results show that transforming institutions, rules and regulations alone does not guarantee a broader engagement of local communities in more ambitious, committed, and lasting climate action, even with a high climate change concern in the population. Creating strategies aimed at more profound cognitive and relational changes from a bottom-up perspective will also be necessary to avoid negative transformation trajectories. |
| The last millennium viewed from a fine-resolution freshwater diatom record from northwestern Patagonia | Quaternary Science Reviews | Sepúlveda-Zúñiga, E.; Maidana, N.; Villacís, L.; Sagredo, E.; Moreno, P. | 2022 | Agua y Extremos | 10.1016/j.quascirev.2022.107806 | https://linkinghub.elsevier.com/retrieve/pii/S0277379122004371 | 107806 | Vol: 296 | 0277-3791 | Thomson Reuters ISI (SCIE) | | English | Little is known about the response of terrestrial and aquatic ecosystems to changes in climatic and human influences during the last millennium in northwestern Patagonia (NWP, 40°-44°S). By virtue of their sensitivity and specificity, diatoms are ideal for examining past changes in aquatic ecosystems and deciphering the ranges of variability under natural and human-induced conditions. To date, however, very few fossils diatom studies have examined in detail the environmental evolution during the last millennium throughout Patagonia. Here we present a fine-resolution diatom record from a lake-sediment core collected from Lago Pichilaguna (41°S), a closed-basin and shallow lake with a small catchment area located in the lowlands of the Chilean Lake District in NWP. The record spans the last millennium with a median time resolution of ∼12 years between samples, and shows abundant small Aulacoseira spp. between ∼1000-900 and ∼600-300 cal yr BP, which alternate in dominance with small fragilarioids and small raphid diatoms between ∼900-600 and ∼300-200 cal yr BP. A rapid shift to planktonic diatoms started at ∼200 cal yr BP and led to their modern dominance. We interpret centennial-scale changes in temperature, precipitation, and lake turbulence, with warm/dry/stratified phases between ∼1000-900 and ∼600-300 cal yr BP related to weak westerly winds, and intervals of cold/wet and mixed water column conditions between ∼900-600 and ∼300-200 cal yr BP, favored by stronger winds. The transition from periphytic to planktonic diatoms that started at ∼200 cal yr BP suggests juxtaposition of the warmest/driest phase of the last millennium and the onset of large-scale disturbance by Chilean/European settlers in NWP. Our results reveal that human disturbance during historical time surpassed the natural ranges of variability and resilience of aquatic and terrestrial ecosystems over the last millennium, generating abrupt changes in biodiversity, species composition, and community structure. © 2022 Elsevier Ltd |
| Glacier fluctuations in the northern Patagonian Andes (44°S) imply wind-modulated interhemispheric in-phase climate shifts during Termination 1 | Scientific Reports | Soteres, R.; Sagredo, E.; Kaplan, M.; Martini, M.; Moreno, P.; Reynhout, S.; Schwartz, R.; Schaefer, J. | 2022 | Agua y Extremos | 10.1038/s41598-022-14921-4 | https://www.nature.com/articles/s41598-022-14921-4 | 10842 | Vol: 12 Issue: 1 | 2045-2322 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Abstract
The Last Glacial Termination (T1) featured major changes in global circulation systems that led to a shift from glacial to interglacial climate. While polar ice cores attest to an antiphased thermal pattern at millennial timescales, recent well-dated moraine records from both hemispheres suggest in-phase fluctuations in glaciers through T1, which is inconsistent with the bipolar see-saw paradigm. Here, we present a glacier chronology based on 30 new
10
Be surface exposure ages from well-preserved moraines in the Lago Palena/General Vintter basin in northern Patagonia (~ 44°S). We find that the main glacier lobe underwent profound retreat after 19.7 ± 0.7 ka. This recessional trend led to the individualization of the Cerro Riñón glacier by ~ 16.3 ka, which underwent minor readvances at 15.9 ± 0.5 ka during Heinrich Stadial 1, during the Antarctic Cold Reversal with successive maxima at 13.5 ± 0.4, 13.1 ± 0.4, and 13.1 ± 0.5 ka, and a minor culmination at 12.5 ± 0.4 ka during Younger Dryas time. We conclude that fluctuations of Patagonian glaciers during T1 were controlled primarily by climate anomalies brought by shifts in the Southern Westerly Winds (SWW) locus. We posit that the global covariation of mountain glaciers during T1 was linked to variations in atmospheric CO
2
(atmCO
2
) promoted by the interplay of the SWW-Southern Ocean system at millennial timescales. |
| Glacial geomorphology of the central and southern Chilotan Archipelago (42.2°S–43.5°S), northwestern Patagonia | Journal of Maps | Soteres, R.; Sagredo, E.; Moreno, P.; Lowell, T.; Alloway, B. | 2022 | Agua y Extremos | 10.1080/17445647.2021.2008538 | https://www.tandfonline.com/doi/full/10.1080/17445647.2021.2008538 | 1-17 | Vol: 18 | 1744-5647 | Thomson Reuters ISI (SCIE; SSCI) | All Open Access; Gold Open Access | English | We present a geomorphic map of the glacial landforms associated with the Golfo Corcovado ice lobe in northwestern Patagonia. Built upon prior studies, our map elaborates on the central and southern sectors of Isla Grande de Chiloé and neighboring islands. Through a combination of remote sensing techniques and exhaustive fieldwork, we identified a suite of ice-marginal, subglacial, and glaciofluvial features created by the Golfo Corcovado ice lobe during four maxima within the last glacial cycle, in none of which the ice-front reached the Pacific coast of Isla Grande de Chiloé. Our mapping builds a foundation and provides insights for future interdisciplinary research on the Late Quaternary sequence of glacial and paleoclimatic events in this key sector of northwestern Patagonia. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. |
| An extraordinary dry season precipitation event in the subtropical Andes: Drivers, impacts and predictability | Weather and Climate Extremes | Valenzuela, R.; Garreaud, R.; Vergara, I.; Campos, D.; Viale, M.; Rondanelli, R. | 2022 | Agua y Extremos; Zonas Costeras | 10.1016/j.wace.2022.100472 | https://linkinghub.elsevier.com/retrieve/pii/S2212094722000548 | 100472 | Vol: 37 | 2212-0947 | Thomson Reuters ISI (SCIE) | | English | A major storm impacted the subtropical Andes during 28–31 January 2021 producing 4-days accumulated precipitation up to 100 mm over central-south Chile. These are high accumulations even for winter events but the storm occurred in the middle of the summer when precipitation is virtually absent, conferring it an extraordinary character. Similar storms have occurred only 2–3 times in the past century. The January 2021 event included periods of high rainfall intensity, hail and lighting, causing dozens of landslides and flash floods with the concomitant social impacts and economical losses. Here we examine the meteorological drivers of this storm at multiples scales, its climatological context, the associated surface impacts, and some aspects of its predictability. About a week before the storm development over central Chile, a large-scale perturbation in the central South Pacific set the stage for the formation of a zonal jet aloft and zonal atmospheric river (ZAR) that extended eastward until reaching the west coast of South America. The ZAR landfalled at 39°S and its subsequent northward displacement resulted in copious orographic precipitation over the Andes and adjacent lowlands, concomitant with a relatively warm environment during the first phase of the storm (28–29 January). During the second phase (30–31 January) the ZAR decayed rapidly but left behind significant amount of water vapor and the formation of a cut-off low (COL) in its poleward flank. The COL facilitated both advection of cyclonic vorticity and cold air at mid-levels, setting the environment for deep convection, intense rain showers, significant lightning activity, and hail. An assessment of the quantitative precipitation forecast (QPF) from the operational Global Forecast System (GFS) indicates that the model captured well the 96-h precipitation accumulation (28–31 January) in terms of timing and spatial extent. However, specific zones with the largest accumulations varied as a function of lead time. The more stable precipitation during the ZAR phase was better predicted than the convective precipitation during the COL phase. Proper dissemination of these forecast and recently established infrastructure contributed to ease the impact of this extraordinary event on the general population. © 2022 The Authors |
| Sclerophyllous Forest Tree Growth Under the Influence of a Historic Megadrought in the Mediterranean Ecoregion of Chile | Ecosystems | Venegas-González, A.; Muñoz, A.; Carpintero-Gibson, S.; González-Reyes, A.; Schneider, I.; Gipolou-Zuñiga, T.; Aguilera-Betti, I.; Roig, F. | 2022 | Agua y Extremos | 10.1007/s10021-022-00760-x | https://link.springer.com/10.1007/s10021-022-00760-x | 344-361 | Vol: 26 | 1432-9840, 1435-0629 | Thomson Reuters ISI (SCIE) | | English | The Mediterranean-type Ecosystems of Central Chile is one of the most threatened regions in South America by global change, particularly evidenced by the historical megadrought that has occurred in central Chile since 2010. The sclerophyllous forest stands out, whose history and relationship with drought conditions has been little studied. Cryptocarya alba and Beilschmiedia miersii (Lauraceae), two large endemic trees, represent an opportunity to analyze the incidence of intense droughts in the growth of sclerophyllous forests by analyzing their tree rings. Here, we considered > 400 trees from nineteen populations of C. alba and B. miersii growing across a latitudinal gradient (32°–35° S). To study the influence of local and large-scale climatic variability on tree growth, we first grouped the sites by species and explored the relationships between tree-growth patterns of C. alba and B. miersii with temperature, precipitation, and climate water deficit (CWD). Second, we performed Principal Component Analysis to detect common modes of variability and to explore relationships between growth patterns and their relationship to Palmer Drought Severity Index (PDSI), ENSO and SAM indices. We detected a breaking point as of 2002 at regional level, where a persistent and pronounced decrease in tree growth occurred, mainly influenced by the increase in CWD and the decrease in winter-spring rainfall. In addition, a positive (negative) relationship was showed between PC1 growth-PDSI and PC1 growth-ENSO (growth-SAM), that is, growth increases (decreases) in the same direction as PDSI and ENSO (SAM). Despite the fact that sclerophyllous populations are highly resistant to drought events, we suggest that the sclerophyllous populations studied here experienced a generalized growth decline, and possibly the natural dynamics of their forests have been altered, mainly due to the accumulating effects of the unprecedented drought since 2010. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature. |
| Sharp Increase of Extreme Turbidity Events Due To Deglaciation in the Subtropical Andes | Journal of Geophysical Research: Earth Surface | Vergara, I.; Garreaud, R.; Ayala, Á. | 2022 | Agua y Extremos | 10.1029/2021JF006584 | https://onlinelibrary.wiley.com/doi/10.1029/2021JF006584 | arte2021JF006584 | Vol: 127 Issue: 6 | 2169-9003, 2169-9011 | Thomson Reuters ISI (SCIE) | | English | Climate change may affect sediment fluvial export from high mountain regions, leading to downstream environmental disruptions and direct impacts on human activities. In this paper, three decades (1990–2020) of turbidity measurements, along with climate and hydro-glaciological variables, were used to investigate the interannual and interdecadal variability in the number of extreme turbidity events (ETE) in the glacierized Maipo River basin, located in the western subtropical Andes. ETE are defined as a sequence of days (most often 1 or 2) during which the daily maximum turbidity was in the 99% quantile of the entire study period. Some of these events compromised the drinking water provision for the city of Santiago, with more than 6 million inhabitants. ETE are more frequent during summer and are mostly associated with melt-favourable conditions. The number of ETE tends to increase in summers with large glacier ice melt and low snowmelt (outside or over glaciers). Most notable, the mean annual number of ETE exhibits a 6-fold increase in the last decade compared with the 1990–2010 period. After 2010, ETE also shifted their seasonal maximum from late spring to mid-summer and their occurrence became strongly coupled with large ice melt rates. We hypothesize that such regime change was caused by an enhanced hydrological connectivity of subglacial sediment pools that increased the sensitivity of the sediment system to glacier melt. The latter is in line with recent research and is consistent with the ongoing glacier retreat due to strong regional warming and drying. © 2022. American Geophysical Union. All Rights Reserved. |
| Exploring the association between landslides and fluvial suspended sediment in a semi-arid basin in central Chile | Geomorphology | Vergara, I.; Garreaud, R.; Moreiras, S.; Araneo, D.; Beigt, D. | 2022 | Agua y Extremos | 10.1016/j.geomorph.2022.108129 | https://linkinghub.elsevier.com/retrieve/pii/S0169555X22000228 | 108129 | Vol: 402 | 0169-555X | Thomson Reuters ISI (SCIE) | | English | The systematic monitoring of landslides is an essential input for their characterization and subsequent reduction of their risk. Along the western subtropical Andes, field monitoring is scarce, so alternative methods that can improve the monitoring are valuable. In this work, the capacity of fluvial suspended sediment to detect the occurrence of landslides in a basin was explored, emphasizing how the relationship varies depending on the hydro-sedimentological variable, the triggering causal factor and the landslide type. The values of suspended sediment concentration (SSC), water discharge (Q) and specific suspended sediment yield (SSY) associated with mass movements were collected from a fluviometric station, as well as maxima of these variables that were not associated with landslides. With these data, different General Linear Models were constructed considering possible non-linear effects of the covariates. Flow-type landslides triggered by rain (most of the events) are correctly predicted, especially using the linear effects of SSC and Q. For this mass movement type the prediction is suitable even for events triggered by isolated, short-lived rains, which are difficult to detect in mountainous areas with meteorological devices. © 2022 Elsevier B.V. |
| Evolution of Glacial Lake Cochrane During the Last Glacial Termination, Central Chilean Patagonia (∼47°S) | Frontiers in Earth Science | Vásquez, A.; Flores-Aqueveque, V.; Sagredo, E.; Hevia, R.; Villa-Martínez, R.; Moreno, P.; Antinao, J. | 2022 | Agua y Extremos | 10.3389/feart.2022.817775 | https://www.frontiersin.org/articles/10.3389/feart.2022.817775/full | 817775 | Vol: 10 | 2296-6463 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Large ice-dammed lakes developed along the eastern margin of the Patagonian Ice Sheet (PIS) during the Last Glacial Termination (T1). Their spatial/temporal evolution, however, remains poorly constrained despite their importance for deciphering fluctuations of the shrinking PIS, isostatic adjustments, and climate forcing. Here we examine the distribution and age of shoreline features deposited or sculpted by Glacial Lake Cochrane (GLC) in the Lago Cochrane/Pueyrredón (LCP) basin, Central Patagonia, following recession of the LCP glacier lobe from its final Last Glacial Maximum (LGM) moraines. GLC drained initially toward the Atlantic Ocean and continuing ice shrinking opened new drainage routes allowing the discharge toward the Pacific Ocean. We identify five clusters of lake terraces, shorelines, and deltas between elevations ∼600–500 (N5), ∼470–400 (N4), ∼360–300 (N3), ∼230–220 (N2), and ∼180–170 masl (N1) throughout the LCP basin. The distribution of these clusters and associated glaciolacustrine deposits provide constraints for the evolving position of the damming glacier bodies. Elevation gradients within the landform clusters reveal glacio-isostatic adjustments that enable us to quantify the magnitude of deglacial rebound and construct isostatically corrected surfaces for the different phases in the evolution of GLC. Our chronology, based principally on radiocarbon dates from lake sediment cores and new OSL dating, suggests that these phases developed between ∼20.7–19.3 ka (N5), ∼19.3–14.8 ka (N4), ∼14.8–11.3 ka (N3), and shortly thereafter (N2 and N1). The N3 landforms are the most ubiquitous, well-preserved, and voluminous, attributes that resulted from a ∼3,500-year long period of glacial stability, enhanced sediment supply by peak precipitation regime, and profuse snow and ice melting during the most recent half of T1. This scenario differs from the cold and dry conditions that prevailed during the brief N5 phase and the moderate amount of precipitation during the N4 phase. We interpret the limited development of the N2 and N1 landforms as ephemeral stabilization events following the final and irreversible disappearance of GLC after N3. This event commenced shortly after the onset of an early Holocene westerly minimum at pan-Patagonian scale at ∼11.7 ka, contemporaneous with peak atmospheric and oceanic temperatures in the middle and high latitudes of the Southern Hemisphere. |
| Analysis of Climate-Related Risks for Chile’s Coastal Settlements in the ARClim Web Platform | Water | Winckler, P.; Contreras-López, M.; Garreaud, R.; Meza, F.; Larraguibel, C.; Esparza, C.; Gelcich, S.; Falvey, M.; Mora, J. | 2022 | Agua y Extremos | 10.3390/w14223594 | https://www.mdpi.com/2073-4441/14/22/3594 | 3594 | Vol: 14 Issue: 22 | 2073-4441 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The web-based tool ARClim provides an atlas of climate change-related risk assessments spanning over 50 environmental and productive sectors in Chile. This paper illustrates the implementation of ARClim on two coastal sectors, operational downtime in fishing coves and flooding in coastal settlements, aiming to provide a tool to visualize comparative estimates of risk, which may enable decision makers and stakeholders to prioritize adaptation measures. The risk is calculated as a function of the hazard, exposure, and sensitivity. Exposure and sensitivity are characterized using present day information. To assess the hazard, wave climate for a historical period (1985–2004) and a projection (2026–2045) were modeled with six general circulation models (GCMs) for an RCP8.5 scenario. Similarly, sea-level rise was computed from 21 GCMs. Results show that the flooding hazard is mostly dependent on sea-level rise, with waves playing a minor role. However, the flooding risk is highly variable along the coast, due to differences in the exposure, which strongly depends on the population of each settlement. The analysis of increased operational downtime in fishing coves also shows risk, which is dependent of the size of each site. Lastly, limitations of the analysis and opportunities for improvement are discussed. |
| Hydrological droughts in the southern Andes (40–45°S) from an ensemble experiment using CMIP5 and CMIP6 models | Scientific Reports | Aguayo, R.; León-Muñoz, J.; Garreaud, R.; Montecinos, A. | 2021 | Agua y Extremos | 10.1038/s41598-021-84807-4 | http://www.nature.com/articles/s41598-021-84807-4 | 5530 | Vol: 11 Issue: 1 | 2045-2322 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The decrease in freshwater input to the coastal system of the Southern Andes (40–45°S) during the last decades has altered the physicochemical characteristics of the coastal water column, causing significant environmental, social and economic consequences. Considering these impacts, the objectives were to analyze historical severe droughts and their climate drivers, and to evaluate the hydrological impacts of climate change in the intermediate future (2040–2070). Hydrological modelling was performed in the Puelo River basin (41°S) using the Water Evaluation and Planning (WEAP) model. The hydrological response and its uncertainty were compared using different combinations of CMIP projects (n = 2), climate models (n = 5), scenarios (n = 3) and univariate statistical downscaling methods (n = 3). The 90 scenarios projected increases in the duration, hydrological deficit and frequency of severe droughts of varying duration (1 to 6 months). The three downscaling methodologies converged to similar results, with no significant differences between them. In contrast, the hydroclimatic projections obtained with the CMIP6 and CMIP5 models found significant climatic (greater trends in summer and autumn) and hydrological (longer droughts) differences. It is recommended that future climate impact assessments adapt the new simulations as more CMIP6 models become available. |
| Recent Changes in the Low-Level Jet along the Subtropical West Coast of South America | Atmosphere | Aguirre, C.; Flores-Aqueveque, V.; Vilches, P.; Vásquez, A.; Rutllant, J.; Garreaud, R. | 2021 | Agua y Extremos; Zonas Costeras | 10.3390/atmos12040465 | https://www.mdpi.com/2073-4433/12/4/465 | 465 | Vol: 12 Issue: 4 | 2073-4433 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Surface winds along the subtropical west coast of South America are characterized by the quasi-weekly occurrences of low-level jet events. These short lived but intense wind events impact the coastal ocean environment. Hence, identifying long-term trends in the coastal low-level jet (CLLJ) is essential for understanding changes in marine ecosystems. Here we use ERA5 reanalysis (1979–2019) and an objective algorithm to track anticyclones to investigate recent changes in CLLJ events off central Chile (25–43 °S). Results present evidence that the number of days with intense wind (≥10 ms−1), and the number and duration of CLLJ events have significantly changed off central Chile in recent decades. There is an increase in the number of CLLJ events in the whole study area during winter (June-July-August; JJA), while during summer (December–January–February; DJF) a decrease is observed at lower latitudes (29–34 °S), and an increase is found at the southern boundary of the Humboldt system. We suggest that changes in the central pressures and frequency of extratropical, migratory anticyclones that reach the coast of South America, which force CLLJs, have played an important role in the recent CLLJ changes observed in this region. |
| High-Frequency Variability of the Surface Ocean Properties Off Central Chile During the Upwelling Season | Frontiers in Marine Science | Aguirre, C.; Garreaud, R.; Belmar, L.; Farías, L.; Ramajo, L.; Barrera, F. | 2021 | Agua y Extremos; Zonas Costeras | 10.3389/fmars.2021.702051 | https://www.frontiersin.org/articles/10.3389/fmars.2021.702051/full | 702051 | Vol: 8 | 2296-7745 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The ocean off south-central Chile is subject to seasonal upwelling whose intensity is mainly controlled by the latitudinal migration of the southeast Pacific subtropical anticyclone. During austral spring and summer, the mean flow is equatorward favoring coastal upwelling, but periods of strong southerly winds are intermixed with periods of relaxed southerlies or weak northerly winds (downwelling favorable). This sub-seasonal, high-frequency variability of the coastal winds results in pronounced changes in oceanographic conditions and air-sea heat and gas exchanges, whose quantitative description has been limited by the lack of
in-situ
monitoring. In this study, high frequency fluctuations of meteorological, oceanographic and biogeochemical near surface variables were analyzed during two consecutive upwelling seasons (2016–17 and 2017–18) using observations from a coastal buoy located in the continental shelf off south-central Chile (36.4°S, 73°W), ∼10 km off the coast. The radiative-driven diel cycle is noticeable in meteorological variables but less pronounced for oceanographic and biogeochemical variables [ocean temperature, nitrate (NO
3
−), partial pressure of carbon dioxide (
p
CO
2
sea
), pH, dissolved oxygen (DO)]. Fluorescence, as a proxy of chlorophyll-
a
, showed diel variations more controlled by biological processes. In the synoptic scale, 23 active upwelling events (strong southerlies, lasting between 2 and 15 days, 6 days in average) were identified, alternated with periods of relaxed southerlies of shorter duration (4.5 days in average). Upwelling events were related to the development of an atmospheric low-level coastal jet in response to an intense along-shore pressure gradient. Physical and biogeochemical surface seawater properties responded to upwelling favorable wind stress with approximately a 12-h lag. During upwelling events, SST, DO and pH decrease, while NO
3
−,
p
CO
2
sea
, and air-sea fluxes increases. During the relaxed southerly wind periods, opposite tendencies were observed. The fluorescence response to wind variations is complex and diverse, but in many cases there was a reduction in the phytoplankton biomass during the upwelling events followed by higher values during wind relaxations. The sub-seasonal variability of the coastal ocean characterized here is important for biogeochemical and productivity studies. |
| Learning from Each Other: An Experience of Capturing Learning for Adaptation to Climate Change | The International Journal of Climate Change: Impacts and Responses | Aldunce, P.; Lillo-Ortega, G.; Araya-Valenzuela, D.; Adler, C.; Ugarte, A. | 2021 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.18848/1835-7156/CGP/v13i01/75-90 | https://cgscholar.com/bookstore/works/learning-from-each-other | 75-90 | Vol: 13 Issue: 1 | 1835-7156 | The International Journal of Climate Change: Impacts and Responses | | English | Local communities are the populations most exposed and the first to respond to the impacts of climate change, and their response capacity depends on several factors. Knowledge acquired about adaptation is one of the most relevant of such determinants. The present study advances an understanding of what people know (or do not know) about climate change adaptation, adaptation measures, and criteria for evaluating adaptation. The applied case study, related to the Chilean Mega Drought, involved a series of workshops carried out to evaluate adaptation practices. Questionnaires, including open questions, applied both before and after the workshop the observation of new learning results from the workshop participation. Results indicate a major knowledge gap in regard to relevant variables for evaluating adaptation practices. New knowledge was gained by the workshop participants, primarily regarding those variables but also related to adaptation practices implemented by other participants. This study provides helpful insights for identifying knowledge gaps and directing efforts to inform adaptation theory and strengthen adaptation practice. © Common Ground Research Networks, Paulina Aldunce, Gloria Lillo-Ortega, Dámare Araya-Valenzuela, Carolina Adler, Ana María Ugarte, All Rights Reserved. |
| Evaluating adaptation to drought in a changing climate: experience at the local scale in the Aconcagua Valley | Climate and Development | Aldunce, P.; Lillo-Ortega, G.; Araya-Valenzuela, D.; Maldonado-Portilla, P.; Gallardo, L. | 2021 | Agua y Extremos; Ciudades Resilientes | 10.1080/17565529.2021.1893150 | https://www.tandfonline.com/doi/full/10.1080/17565529.2021.1893150 | 121-132 | Vol: 14 Issue: 2 | 1756-5529, 1756-5537 | Thomson Reuters ISI (SSCI) | | English | Since 2010, a severe drought has affected central Chile, resulting in losses that prompt the need to evaluate and improve adaptation responses. The evaluation process requires the engagement of multiple actors in order to collect knowledge of their experiences and to inform future design and implementation of adaptation responses. A case study was conducted in four counties of the Aconcagua Valley, Chile, to evaluate the usefulness of existing drought response measures, and to identify strengths and weaknesses, and relevant actors’ recommendations for overcoming them. We applied the Index for the Usefulness of Adaptation Practices (IUPA), a multi-criteria tool that systematically identifies the perceived usefulness of measures. The most salient strengths of the evaluated measures were: replicability, pertinence, and efficacy; representing key factors that could facilitate the implementation of drought responses in similar contexts. The most salient weaknesses were: lack of integration with other policy domains and projects, low environmental protection, diminished autonomy in decision-making, and inequity. Proposed recommendations to overcome these weaknesses have real potential for implementation because they emerged from local actors. Results present empirical evidence of the utility of participatory approaches for a context-specific evaluation of measures, contributing to enhance adaptation to climate variability and change. |
| Enfoque Transformación: Adaptación | | Aldunce, P.; Rojas, M.; Guevara, G.; Álvarez, C.; Billi, M.; Ibarra, C.; Sapiains, R. | 2021 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política | | https://www.cr2.cl/wp-content/uploads/2021/10/transformacion_adaptacion.pdf | | | | | | | El presente documento es un marco conceptual para la incorporación del enfoque
de transformación en las investigaciones de cambio climático con énfasis en la
adaptación y tiene el propósito de apoyar la aplicación del enfoque al trabajo de
investigación del (CR)2 a través de los Temas Integrativos de Floración de Algas Nocivas (FAN), de Seguridad Hídrica (TISHi) y de Gobernanza climática de los elementos.
El enfoque de transformación se compone de distintos conceptos y alcances, de los
que este documento presenta lo medular en tres secciones: (1) Conceptualización
de la transformación y conceptos relacionados; (2) Transformación y adaptación; y
(3) Preguntas orientadoras para la implementación del enfoque de la transformación. |
| Progressive water deficits during multiyear droughts in basins with long hydrological memory in Chile | Hydrology and Earth System Sciences | Alvarez-Garreton, C.; Boisier, J.; Garreaud, R.; Seibert, J.; Vis, M. | 2021 | Agua y Extremos | 10.5194/hess-25-429-2021 | https://hess.copernicus.org/articles/25/429/2021/ | 429-446 | Vol: 25 Issue: 1 | 1607-7938 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access; Green Open Access | English | A decade-long (2010–2020) period with precipitation deficits in central–south Chile (30–41∘ S), the so-called megadrought (MD), has led to streamflow depletions of larger amplitude than expected from precipitation anomalies, indicating an intensification in drought propagation. We analysed the catchment characteristics and runoff mechanisms modulating such intensification by using the CAMELS-CL dataset and simulations from the HBV hydrological model. We compared annual precipitation–runoff (P–R) relationships before and during the MD across 106 basins with varying snow-/rainfall regimes and identified those catchments where drought propagation was intensified. Our results show that catchments' hydrological memory – modulated by snow and groundwater – is a key control of drought propagation. Snow-dominated catchments (30–35∘ S) feature larger groundwater contribution to streamflow than pluvial basins, which we relate to the infiltration of snowmelt over the Western Andean Front. This leads to longer memory in these basins, represented by a significative correlation between autumn streamflow (when snow has already melted) and the precipitation from the preceding year. Hence, under persistent drought conditions, snow-dominated catchments accumulate the effects of precipitation deficits and progressively generate less water, compared with their historical behaviour, notably affecting central Chile, a region with limited water supply and which concentrates most of the country's population and water demands. Finally, we addressed a general question: what is worse – an extreme single-year drought or a persistent moderate drought? In snow-dominated basins, where water provision strongly depends on both the current and previous precipitation seasons, an extreme drought induces larger absolute streamflow deficits; however persistent deficits induce a more intensified propagation of the meteorological drought. Hence, the worst scenario would be an extreme meteorological drought following consecutive years of precipitation below average, as occurred in 2019. In pluvial basins of southern Chile
(35–41∘ S), hydrologic memory is still an important factor, but water supply is more strongly dependant on the meteorological conditions of the current year, and therefore an extreme drought would have a higher impact on water supply than a persistent but moderate drought. |
| Radiocarbon bomb-peak signal in tree-rings from the tropical Andes register low latitude atmospheric dynamics in the Southern Hemisphere | Science of The Total Environment | Ancapichún, S.; De Pol-Holz, R.; Christie, D.; Santos, G.; Collado-Fabbri, S.; Garreaud, R.; Lambert, F.; Orfanoz-Cheuquelaf, A.; Rojas, M.; Southon, J.; Turnbull, J.; Creasman, P. | 2021 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política | 10.1016/j.scitotenv.2021.145126 | https://linkinghub.elsevier.com/retrieve/pii/S0048969721001923 | 145126 | Vol: 774 | 00489697 | Thomson Reuters ISI (SCIE) | | English | South American tropical climate is strongly related to the tropical low-pressure belt associated with the South American monsoon system. Despite its central societal role as a modulating agent of rainfall in tropical South America, its long-term dynamical variability is still poorly understood. Here we combine a new (and world's highest) tree-ring 14C record from the Altiplano plateau in the central Andes with other 14C records from the Southern Hemisphere during the second half of the 20th century in order to elucidate the latitudinal gradients associated with the dissemination of the bomb 14C signal. Our tree-ring 14C record faithfully captured the bomb signal of the 1960's with an excellent match to atmospheric 14C measured in New Zealand but with significant differences with a recent record from Southeast Brazil located at almost equal latitude. These results imply that the spreading of the bomb signal throughout the Southern Hemisphere was a complex process that depended on atmospheric dynamics and surface topography generating reversals on the expected north-south gradient in certain years. We applied air-parcel modeling based on climate data to disentangle their different geographical provenances and their preformed (reservoir affected) radiocarbon content. We found that air parcel trajectories arriving at the Altiplano during the bomb period were sourced i) from the boundary layer in contact with the Pacific Ocean (41%), ii) from the upper troposphere (air above the boundary layer, with no contact with oceanic or continental carbon reservoirs) (38%) and iii) from the Amazon basin (21%). Based on these results we estimated the ∆14C endmember values for the different carbon reservoirs affecting our record which suggest that the Amazon basin biospheric 14C isoflux could have been reversed from negative to positive as early as the beginning of the 1970's. This would imply a much faster carbon turnover rate in the Amazon than previously modelled. |
| Spatiotemporal Peatland Productivity and Climate Relationships Across the Western South American Altiplano | Journal of Geophysical Research: Biogeosciences | Anderson, T.; Christie, D.; Chávez, R.; Olea, M.; Anchukaitis, K. | 2021 | Agua y Extremos | 10.1029/2020JG005994 | https://onlinelibrary.wiley.com/doi/10.1029/2020JG005994 | art: e2020JG005994 | Vol: 126 Issue: 6 | 2169-8953, 2169-8961 | Thomson Reuters ISI (SCIE) | | English | The South American Altiplano is one of the largest semiarid high-altitude plateaus in the world. Within the Altiplano, peatlands known as “bofedales” are important components of regional hydrology and provide key water resources and ecosystem services to Andean communities. Warming temperatures, changes in hydroclimate, and shifting atmospheric circulation patterns all affect peatland dynamics and hydrology. It is therefore urgent to better understand the relationships between climate variability and the spatiotemporal variations in peatland productivity across the Altiplano. Here, we explore climate influences on peatland vegetation using 31 years of Landsat data. We focus specifically on the bofedal network in the western Altiplano, the driest sector of the plateau, and use the satellite-derived Normalized Difference Vegetation Index (NDVI) as an indicator of productivity. We develop temporally and spatially continuous NDVI products at multiple scales in order to evaluate relationships with climate variables over the past three decades. We demonstrate that cumulative precipitation and snow persistence over the prior 2 years are strongly associated with growing season productivity. A step change in peatland productivity between 2013–2015 drives an increasing trend in NDVI and is likely a response to consecutive years of anomalously high snow accumulation and rainfall. Early summer minimum temperatures emerge as a secondary influence on productivity. Understanding large-scale productivity dynamics and characterizing the response of bofedales to climate variability over the last three decades provides a baseline to monitor the responses of Andean peatlands to climate change. |
| On the selection of precipitation products for the regionalisation of hydrological model parameters | Hydrology and Earth System Sciences | Baez-Villanueva, O.; Zambrano-Bigiarini, M.; Mendoza, P.; McNamara, I.; Beck, H.; Thurner, J.; Nauditt, A.; Ribbe, L.; Thinh, N. | 2021 | Agua y Extremos | 10.5194/hess-25-5805-2021 | https://hess.copernicus.org/articles/25/5805/2021/ | 5805-5837 | Vol: 25 Issue: 11 | 1607-7938 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Over the past decades, novel parameter regionalisation techniques have been developed to predict streamflow in data-scarce regions. In this paper, we examined how the choice of gridded daily precipitation (P) products affects the relative performance of three well-known parameter regionalisation techniques (spatial proximity, feature similarity, and parameter regression) over 100 near-natural catchments with diverse hydrological regimes across Chile. We set up and calibrated a conceptual semi-distributed HBV-like hydrological model (TUWmodel) for each catchment, using four P products (CR2MET, RF-MEP, ERA5, and MSWEPv2.8). We assessed the ability of these regionalisation techniques to transfer the parameters of a rainfall-runoff model, implementing a leave-one-out cross-validation procedure for each P product. Despite differences in the spatio-temporal distribution of P, all products provided good performance during calibration (median Kling–Gupta efficiencies (KGE′s) > 0.77), two independent verification periods (median KGE′s >0.70 and 0.61, for near-normal and dry conditions, respectively), and regionalisation (median KGE′s for the best method ranging from 0.56 to 0.63). We show how model calibration is able to compensate, to some extent, differences between P forcings by adjusting model parameters and thus the water balance components. Overall, feature similarity provided the best results, followed by spatial proximity, while parameter regression resulted in the worst performance, reinforcing the importance of transferring complete model parameter sets to ungauged catchments. Our results suggest that (i) merging P products and ground-based measurements does not necessarily translate into an improved hydrologic model performance; (ii) the spatial resolution of P products does not substantially affect the regionalisation performance; (iii) a P product that provides the best individual model performance during calibration and verification does not necessarily yield the best performance in terms of parameter regionalisation; and (iv) the model parameters and the performance of regionalisation methods are affected by the hydrological regime, with the best results for spatial proximity and feature similarity obtained for rain-dominated catchments with a minor snowmelt component. |
| Water management or megadrought: what caused the Chilean Aculeo Lake drying? | Regional Environmental Change | Barría, P.; Chadwick, C.; Ocampo-Melgar, A.; Galleguillos, M.; Garreaud, R.; Díaz-Vasconcellos, R.; Poblete, D.; Rubio-Álvarez, E.; Poblete-Caballero, D. | 2021 | Agua y Extremos; Cambio de Uso de Suelo | 10.1007/s10113-021-01750-w | http://link.springer.com/10.1007/s10113-021-01750-w | 19 | Vol: 21 Issue: 1 | 1436-3798, 1436-378X | Thomson Reuters ISI (SCIE; SSCI) | | English | The Aculeo Lake is an important natural reservoir of Central Chile, which provides valuable ecosystem services. This lake has suffered a rapid shrinkage of the water levels from year 2010 to 2018, and since October 2018, it is completely dry. This natural disaster is concurrent with a number of severe and uninterrupted drought years, along with sustained increases in water consumption associated to land use/land cover (LULC) changes. Severe water shortages and socio-environmental impacts were triggered by these changes, emphasizing the need to understand the causes of the lake desiccation to contribute in the design of future adaptation strategies. Thereby, the Water Evaluation and Planning (WEAP) hydrological model was used as a tool to quantify the water balance in the catchment. The model was run under a combination of three land use/land cover and two different climate scenarios that sample the cases with and without megadrought and with or without changes in land use. According to the results, the main triggering factor of the lake shrinkage is the severe megadrought, with annual rainfall deficits of about 38%, which resulted in amplified reductions in river flows (44%) and aquifer recharges (24%). The results indicate that the relative impact of the climate factor is more than 10 times larger than the impact of the observed LULC changes in the lake balance, highlighting the urgent need for adaptation strategies to deal with the projected drier futures. |
| Water allocation under climate change | Elementa: Science of the Anthropocene | Barría, P.; Sandoval, I.; Guzman, C.; Chadwick, C.; Alvarez-Garreton, C.; Díaz-Vasconcellos, R.; Ocampo-Melgar, A.; Fuster, R. | 2021 | Agua y Extremos | 10.1525/elementa.2020.00131 | https://online.ucpress.edu/elementa/article/9/1/00131/117183/Water-allocation-under-climate-changeA-diagnosis | 00131 | Vol: 9 Issue: 1 | 2325-1026 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Chile is positioned in the 20th rank of water availability per capita. Nonetheless, water security levels vary across the territory. Around 70% of the national population lives in arid and semiarid regions, where a persistent drought has been experienced over the last decade. This has led to water security problems including water shortages. The water allocation and trading system in Chile is based on a water use rights (WURs) market, with limited regulatory and supervisory mechanisms, where the volume to be granted as permanent and eventual WURs is calculated from statistical analyses of historical streamflow records if available, or from empirical estimations if they are not. This computation of WURs does not consider the nonstationarity of hydrological processes nor climatic projections. This study presents the first large sample diagnosis of water allocation system in Chile under climate change scenarios. This is based on novel anthropic intervention indices (IAI), which were computed as the ratio between the total granted water volume to the water availability within 87 basins in north-central and southern Chile (30°S–42°S). The IAI were evaluated for the historical period (1979–2019) and under modeled-based climatic projections (2055–2080). According to these IAI levels, to date, there are 20 out of 87 overallocated basins, which under the assumption that no further WURs will be granted in the future, increases up to 25 basins for the 2055–2080 period. The results show that, to date most of north-central Chilean catchments already have a large anthropic intervention degree, and the increases for the future period occurs mostly in the southern region of the country (approximately 38°S), which has been considered as possible source of water for large water transfer projects (i.e., water roads). These indices and diagnosis are proposed as a tool to help policy makers to address water scarcity under climate change. |
| Mapping water ecosystem services: Evaluating InVEST model predictions in data scarce regions | Environmental Modelling & Software | Benra, F.; De Frutos, A.; Gaglio, M.; Álvarez-Garretón, C.; Felipe-Lucia, M.; Bonn, A. | 2021 | Agua y Extremos | 10.1016/j.envsoft.2021.104982 | https://linkinghub.elsevier.com/retrieve/pii/S1364815221000256 | 104982 | Vol: 138 | 13648152 | Thomson Reuters ISI (SCIE) | | English | Sustainable management of water ecosystem services requires reliable information to support decision making. We evaluate the performance of the InVEST Seasonal Water Yield Model (SWYM) against water monitoring records in 224 catchments in southern Chile. We run the SWYM in three years (1998, 2007 and 2013) to account for recent land-use change and climatic variations. We computed squared Pearson correlations between SWYM monthly quickflow predictions and streamflow observations and applied a generalized mixed‐effects model to evaluate annual estimations. Results show relatively low monthly correlations with marked latitudinal and temporal variations while annual estimates show a good match between observed and modeled values, especially for values under 1000 mm/year. Better predictions were observed in regions with high rainfall and in dry years while poorer predictions were found in snow dominated and drier regions. Our results improve SWYM performance and contribute to water supply and regulation decision-making, particularly in data scarce regions. |
| Chemical Signals in Tree Rings from Northern Patagonia as Indicators of Calbuco Volcano Eruptions since the 16th Century | Forests | Bertin, L.; Christie, D.; Sheppard, P.; Muñoz, A.; Lara, A.; Alvarez, C. | 2021 | Agua y Extremos; Cambio de Uso de Suelo | 10.3390/f12101305 | https://www.mdpi.com/1999-4907/12/10/1305 | 1305 | Vol: 12 Issue: 10 | 1999-4907 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The Calbuco volcano ranks third in the specific risk classification of volcanoes in Chile and has a detailed eruption record since 1853. During 2015, Calbuco had a sub-Plinian eruption with negative impacts in Chile and Argentina, highlighting the need to determine the long-term history of its activity at a high-resolution time scale to obtain a better understanding of its eruptive frequency. We developed a continuous eruptive record of Calbuco for the 1514–2016 period by dendrochemical analysis of Fitzroya cupressoides tree rings at a biennium resolution using inductively coupled plasma–mass spectrometry. After comparing the chemical record of 20 elements contained in tree rings with historical eruptions, one group exhibited positive anomalies during (Pb/Sn) and immediately after (Mo/P/Zn/Cu) eruptions, with a Volcanic Explosivity Index (VEI) ≥ 3, and so were classified as chemical tracers of past eruptions (TPE). The tree-ring width chronology also exhibited significant decreases in tree growth associated with eruptions of VEI ≥ 3. According to these records, we identified 11 new eruptive events of Calbuco, extending its eruptive chronology back to the 16th century and determining a mean eruptive frequency of ~23 years. Our results show the potential to use dendrochemical analysis to infer past volcanic eruptions in Northern Patagonia. This information provides a long-term perspective for assessing eruptive history in Northern Patagonia, with implications for territorial planning. |
| Informe a las Naciones: Gobernanza Climática de los Elementos. Hacia una gobernanza climática del agua, el aire, el fuego y la tierra en Chile, integrada, anticipatoria, socio-ecosistémica y fundada en evidencia. | | Billi, M.; Moraga, P.; Aliste, E, E.; Maillet, A.; O'Ryan, R.; Sapiains A., R.; Bórquez, R.; Aldunce, P.; Azócar, G.; Blanco, G.; Carrasco, N.; Galleguillos, M.; Hervé, D.; Ibarra, C.; Gallardo, L.; Inostroza, V.; Lambert, F.; Manuschevic, D.; Martínez, F.; Osses, M.; Rivas, N.; Rojas, M.; Seguel, R... | 2021 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política | | https://bit.ly/3JdvVbd | 69 | | | cr2.cl | | | La humanidad se ha vuelto una de las mayores fuerzas transformadoras del planeta, generando cambios significativos (y en ocasiones irreversibles) en los
equilibrios geofísicos y ecológicos, con consecuencias
potencialmente catastróficas y en parte aún desconocidas (Foster et al., 2017; Rockström et al., 2009; Steffen
et al., 2007). Entre todas estas alteraciones, el cambio
climático adquiere una importancia preponderante
debido a la magnitud y escala de sus posibles consecuencias, así como por la complejidad y las controversias que ha caracterizado los intentos de hacerle frente
(de Coninck et al., 2018; IPCC, 2018). Contemplar este escenario implica un doble dilema. Por un lado, supone la
necesidad de acciones urgentes, concertadas y transformativas, en múltiples escalas y dominios, que lleven
a hacerse cargo de los forzantes que causan el cambio
climático, sus efectos significativos y desiguales en distintos territorios y poblaciones. Por el otro, se enfrenta
a la insuficiencia, parcialidad y limitación demostrada
por los modelos tradicionales de gobernanza para enfrentar estos desafíos. |
| Report to the Nations Climate Governance of the Elements. Towards an Integrated, anticipatory, socio- ecosystemic and evidence- based climate governance of water, air, fire and land. | | Billi, M.; Moraga, P.; Aliste, E, E.; Maillet, A.; O'Ryan, R.; Sapiains A., R.; Bórquez, R.; Aldunce, P.; Azócar, G.; Blanco, G.; Carrasco, N.; Galleguillos, M.; Hervé, D.; Ibarra, C.; Gallardo, L.; Inostroza, V.; Lambert, F.; Manuschevic, D.; Martínez, F.; Osses, M.; Rivas, N.; Rojas, M.; Seguel, R... | 2021 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política | | https://bit.ly/3JdvVbd | 69 | | | | | | Humanity has become one of the greatest transformative forces of the planet, generating significant (and
sometimes irreversible) changes in geophysical and
ecological balances with potentially catastrophic and
partly still unknown consequences (Foster et al., 2017;
Rockström et al., 2009; Steffen et al, 2007). Among all
these alterations, climate change possesses predominant importance due to the magnitude and scale of
its potential consequences, as well as the complexity
and the controversies that have characterized the attempts to address it (Coninck et al, 2018; IPCC, 2018).
Contemplating this scenario entails a double dilemma.
On one hand, it implies the need for urgent, coordinated and transformative actions on multiple scales and
domains that address the drivers that cause climate
change, as well as its significant and unequal effects
on different territories and populations. On the other,
it faces the insufficiency, biases and limitations shown
by traditional governance models in dealing with these
challenges. |
| Temperature and precipitation projections for the Antarctic Peninsula over the next two decades: contrasting global and regional climate model simulations | Climate Dynamics | Bozkurt, D.; Bromwich, D.; Carrasco, J.; Rondanelli, R. | 2021 | Agua y Extremos; Zonas Costeras | 10.1007/s00382-021-05667-2 | http://link.springer.com/10.1007/s00382-021-05667-2 | 3853-3874 | Vol: 56 Issue: 11-12 | 0930-7575, 1432-0894 | Thomson Reuters ISI (SCIE) | | English | This study presents near future (2020–2044) temperature and precipitation changes over the Antarctic Peninsula under the high-emission scenario (RCP8.5). We make use of historical and projected simulations from 19 global climate models (GCMs) participating in Coupled Model Intercomparison Project phase 5 (CMIP5). We compare and contrast GCMs projections with two groups of regional climate model simulations (RCMs): (1) high resolution (15-km) simulations performed with Polar-WRF model forced with bias-corrected NCAR-CESM1 (NC-CORR) over the Antarctic Peninsula, (2) medium resolution (50-km) simulations of KNMI-RACMO21P forced with EC-EARTH (EC) obtained from the CORDEX-Antarctica. A further comparison of historical simulations (1981–2005) with respect to ERA5 reanalysis is also included for circulation patterns and near-surface temperature climatology. In general, both RCM boundary conditions represent well the main circulation patterns of the historical period. Nonetheless, there are important differences in projections such as a notable deepening and weakening of the Amundsen Sea Low in EC and NC-CORR, respectively. Mean annual near-surface temperatures are projected to increase by about 0.5–1.5 ∘C across the entire peninsula. Temperature increase is more substantial in autumn and winter (∼ 2 ∘C). Following opposite circulation pattern changes, both EC and NC-CORR exhibit different warming rates, indicating a possible continuation of natural decadal variability. Although generally showing similar temperature changes, RCM projections show less warming and a smaller increase in melt days in the Larsen Ice Shelf compared to their respective driving fields. Regarding precipitation, there is a broad agreement among the simulations, indicating an increase in mean annual precipitation (∼ 5 to 10%). However, RCMs show some notable differences over the Larsen Ice Shelf where total precipitation decreases (for RACMO) and shows a small increase in rain frequency. We conclude that it seems still difficult to get consistent projections from GCMs for the Antarctic Peninsula as depicted in both RCM boundary conditions. In addition, dominant and common changes from the boundary conditions are largely evident in the RCM simulations. We argue that added value of RCM projections is driven by processes shaped by finer local details and different physics schemes that are introduced by RCMs, particularly over the Larsen Ice Shelf. |
| Influence of African Atmospheric Rivers on Precipitation and Snowmelt in the Near East's Highlands | Journal of Geophysical Research: Atmospheres | Bozkurt, D.; Sen, O.; Ezber, Y.; Guan, B.; Viale, M.; Caglar, F. | 2021 | Agua y Extremos | 10.1029/2020JD033646 | https://onlinelibrary.wiley.com/doi/10.1029/2020JD033646 | art: e2020JD033646 | Vol: 126 Issue: 4 | 2169-897X | Thomson Reuters ISI (SCIE) | | English | Atmospheric rivers (ARs) traveling thousands of kilometers over arid North Africa could interact with the highlands of the Near East (NE), and thus affect the region's hydrometeorology and water resources. Here, we use a state-of-the-art AR tracking database, and reanalysis and observational datasets to investigate the climatology (1979–2017) and influences of these ARs in snowmelt season (March–April). The Red Sea and northeast Africa are found to be the major source regions of these ARs, which are typically associated with the eastern Mediterranean trough positioned over the Balkan Peninsula and a blocking anticyclone over the NE-Caspian region, triggering southwesterly air flow toward the NE's highlands. Approximately 8% of the ARs are relatively strong (integrated water vapor transport>275kg m1 s1). AR days exhibit enhanced precipitation over the crescent-shaped orography of the NE region. Mean AR days indicate wetter (up to+2mm day1) and warmer (up to+1.5°C) conditions than all-day climatology. On AR days, while snowpack tends to decrease (up to 30%) in the Zagros Mountains, it can show decreases or increases in the Taurus Mountains depending largely on elevation. A further analysis with the observations and reanalysis indicates that extreme ARs coinciding with large scale sensible heat transport can significantly increase the daily discharges. These results suggest that ARs can have notable impacts on the hydrometeorology and water resources of the region, particularly of lowland Mesopotamia, a region that is famous with great floods in the ancient narratives. |
| Observatorio de Nieve en los Andes de Argentina y Chile. Instituto Argentino de Nivología, Glaciología, y Ciencias Ambientales (IANIGLA-CONICET). Centro de Ciencia del Clima y la Resiliencia (CR)². | | Cara, L.; Masiokas, M.; Villalba, R.; Garreaud, R.; Christie, D. | 2021 | Agua y Extremos | 10.13140/RG.2.2.11321.70245 | http://rgdoi.net/10.13140/RG.2.2.11321.70245 | | | | | | Spanish | |
| Extreme sea levels at Rapa Nui (Easter Island) during intense atmospheric rivers | Natural Hazards | Carvajal, M.; Winckler, P.; Garreaud, R.; Igualt, F.; Contreras-López, M.; Averil, P.; Cisternas, M.; Gubler, A.; Breuer, W. | 2021 | Agua y Extremos | 10.1007/s11069-020-04462-2 | http://link.springer.com/10.1007/s11069-020-04462-2 | 1619-1637 | Vol: 106 Issue: 2 | 0921-030X, 1573-0840 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | In addition to the tsunami hazard posed by distant great earthquakes, Rapa Nui (Easter Island), in the Southeast Pacific Ocean, is exposed to frequent and intense coastal storms. Here, we use sea-level records and field surveys guided by video and photographic footage to show that extreme sea levels at Rapa Nui occur much more frequent than previously thought and thus constitute an unrecognized hazard to the inland’s maritime supply chain. We found that extreme sea-level events, including the two most extreme (March 5th and May 5th, 2020) in our 17-month-long analyzed period (from January 1st, 2019, to May 31st, 2020), resulted from constructive superpositions of seiches on the shelf, storm surges and high tides. By further analyzing time series of atmospheric and wind-generated wave data, we conclude that these extreme sea levels are ultimately driven by the breaking of large waves near the coastline (i.e., wave setup), with lesser contribution of barometric setup and even less of wind setup. We also propose that these large waves were mainly generated from strong, long-lasting, NW winds associated with intense atmospheric rivers (long, narrow regions in the atmosphere that transport abundant water vapor) passing over Rapa Nui. Given that the intensity of atmospheric rivers and sea level are thought to increase as climate changes, a deeper understanding of the relation between meteorological and oceanographic processes at Rapa Nui is strongly needed. |
| Identifying key driving mechanisms of heat waves in central Chile | Climate Dynamics | Demortier, A.; Bozkurt, D.; Jacques-Coper, M. | 2021 | Agua y Extremos; Zonas Costeras | 10.1007/s00382-021-05810-z | https://link.springer.com/10.1007/s00382-021-05810-z | 2415-2432 | Vol: 57 Issue: 9-10 | 0930-7575, 1432-0894 | Thomson Reuters ISI (SCIE) | | English | This study explores the main drivers of heat wave (HW) events in central Chile using state-of-the-art reanalysis data (ERA5) and observations during the extended austral summer season (November to March) for the period 1979–2018. Frequency and intensity aspects of the HW events are considered using the total number of the HW events per season and the amplitude. We first contrast ERA5 with several surface meteorological stations in central Chile to evaluate its ability to capture daily maximum temperature variability and the HW events. We then use synoptic- and large-scale fields and teleconnection patterns to address the most favorable conditions of the HW events from a climatological perspective as well as from the extreme January 2017 HW event that swept central Chile with temperature records and wildfires. ERA5 tends to capture temperature extremes and the HW events at the inland stations; on the contrary, it has difficulties in capturing the maximum temperature variability at the coastal stations, which is plausible given the complex terrain features and confined coastal climate zone (only ∼ 7% of all grid boxes within central Chile). The composite HW days based on ERA5 reveals a mid-level trough-ridge dipole pattern exhibiting a blocking anticyclone on the surface over a large part of southwest South America. Relatively dry and warm easterly flow appears to accompany the anomalous warming in a large part of central Chile. The temporal evolution of the HW events yields a wave-like propagation pattern and enhancement of trough-ridge pattern along the South Pacific. This meridional dipole pattern is found to be largely associated with the Pacific South American pattern. In addition, the Madden–Julian Oscillation (MJO) appears to be a key component of the HW events in central Chile. In particular, while active MJO phases 2 and 7 promote sub-seasonal patterns that favor the South Pacific dipole mode, synoptic anomalies can superimpose on them and favor the formation of a migrating anticyclone over central-southern Chile and coastal lows over central Chile. Agreeing with the climatological findings, the extreme January 2017 HW analysis suggests that an eastward migratory mid-latitude trough-ridge pattern associated with MJO phase 2 was at work. We highlight that in addition to large- and synoptic-scale features, sub-synoptic processes such as coastal lows can have an important role in shaping the HW events and can lead to amplification of temperature extremes during the HW events. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. |
| Multiscale physical background to an exceptional harmful algal bloom of Dinophysis acuta in a fjord system | Science of The Total Environment | Díaz, P.; Peréz-Santos, I.; Álvarez, G.; Garreaud, R.; Pinilla, E.; Díaz, M.; Sandoval, A.; Araya, M.; Álvarez, F.; Rengel, J.; Montero, P.; Pizarro, G.; López, L.; Iriarte, L.; Igor, G.; Reguera, B. | 2021 | Agua y Extremos | 10.1016/j.scitotenv.2021.145621 | https://linkinghub.elsevier.com/retrieve/pii/S0048969721006896 | 145621 | Vol: 773 | 00489697 | Thomson Reuters ISI (SCIE) | | English | Dinophysis acuta produces diarrhetic shellfish poisoning (DSP) toxins and pectenotoxins (PTX). It blooms in thermally-stratified shelf waters in late summer in temperate to cold temperate latitudes. Despite its major contribution to shellfish harvesting bans, little effort has been devoted to study its population dynamics in Chilean Patagonia. In 2017–2018, mesoscale distribution of harmful algal species (75 monitoring stations) revealed the initiation (late spring) and seasonal growth of a dense D. acuta population in the Aysén region, with maximal values at Puyuhuapi Fjord (PF). Vertical phytoplankton distribution and fine-resolution measurements of physical parameters along a 25-km transect in February 16th identified a 15-km (horizontal extension) subsurface thin layer of D. acuta from 4 to 8 m depth. This layer, disrupted at the confluence of PF with the Magdalena Sound, peaked at the top of the pycnocline (6 m, 15.9 °C, 23.4 psu) where static stability was maximal. By February 22nd, it deepened (8 m, 15.5 °C; 23.62 psu) following the excursions of the pycnocline and reached the highest density ever recorded (664 × 103 cells L−1) for this species. Dinophysis acuta was the dominant Dinophysis species in all microplankton net-tows/bottle samples; they all contained DSP toxins (OA, DTX-1) and PTX-2. Modeled flushing rates showed that Puyuhuapi, the only fjord in the area with 2 connections with the open sea, had the highest water residence time. Long term climate variability in the Southern hemisphere showed the effects of a Southern Annular Mode (SAM) in positive mode (+1.1 hPa) overwhelming a moderate La Niña. These effects included positive spring precipitation anomalies with enhanced salinity gradients and summer drought with positive anomalies in air (+1 °C) and sea surface (+2 °C) temperature. Locally, persistent thermal stratification in PF seemed to provide an optimal physical habitat for initiation and bloom development of D. acuta. Thus, in summer 2018, a favourable combination of meteorological and hydrographic processes of multiple scales created conditions that promoted the development of a widespread bloom of D. acuta with its epicentre at the head of Puyuhuapi fjord. |
| Validation of a 9-km WRF dynamical downscaling of temperature and precipitation for the period 1980–2005 over Central South Chile | Theoretical and Applied Climatology | Fernández, A.; Schumacher, V.; Ciocca, I.; Rifo, A.; Muñoz, A.; Justino, F. | 2021 | Agua y Extremos | 10.1007/s00704-020-03416-9 | http://link.springer.com/10.1007/s00704-020-03416-9 | 361-378 | Vol: 143 Issue: 1-2 | 0177-798X, 1434-4483 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | In this paper, we evaluated a dynamical downscaling produced for Central South Chile (32°S–38°S) relative to climatic conditions between 1980 and 2005. Assessing the skill of dynamical downscaling relative to the present climate is key to determine the degree of confidence on regional climatic projections. We used the Weather Research and Forecasting model to simulate that period at ~ 9 km grid-cell size, forced by the bias-corrected Community Earth System Model. Results indicated that the dynamical downscaling adequately reproduced spatio-temporal features of the climate within the region. Temperature showed a positive bias at the annual scale while the opposite occurred for precipitation. The bias varied when the comparison was performed relative to a gridded product or instrumental records from weather stations. At the monthly scale, the model failed to capture long-term trends relative to the gridded dataset while reproducing spatial patterns, especially for temperature. We found a generally statistically significant spatial clustering of the monthly mean bias that can support implementation and application of dynamical downscaling and bias-correction methods that account for the distinct climatic features of the study area. In particular, the strip 34°S–35°S presented features that are coincident with previous findings suggesting this latitude to be a boundary between different climate regimes north and south. According to our results, we assert that this dynamical downscaling is comparable with other available databases and thus can be utilized in future studies as an additional and independent source of analysis, contributing to a balanced appraisal of climate scenarios for policymaking within the region. |
| Explorador del Atlas de Sequías de Sudamérica, https://sada.cr2.cl | | Ferrada, A.; Christie, D.; Muñoz, F.; Reyes, A.; Garreaud, R.; Bustos, S. | 2021 | Agua y Extremos | 10.13140/RG.2.2.14020.35209 | http://rgdoi.net/10.13140/RG.2.2.14020.35209 | | | | ResearchGate | | Spanish | |
| He Antropoceno i a Tire: he mata ꞌite he haka pūai | | Gallardo, L.; Rudnick, A.; Barraza, J.; Fleming, Z.; Rojas, M.; Gayó, E.; Aguirre, C.; Farías, L.; Boisier, J.; Garreaud, R.; Barría, P.; Miranda, A.; Lara, A.; Gómez, S.; Arriagada, R. | 2021 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://bit.ly/3sAJOdv | | | | | | | Centro de Ciencia del Clima y la Resiliencia mew (CR)2, ta
iñ kvzawkan mew zujiyiñ fey ta nvxamkagelu Anxopozeno
zugu mew ta iñ inarumeael ka ta iñ gvnezuamael. Femgeci
ta cijkatuyiñ cumgeci cambio climático vñfitumapukey
kiñeke mapu mew Cile mew fanten mew, ta iñ kejuael
zugu mew cew ta cijkatugekey ka gvnezuamgekey weke
rvpv ta iñ kvme wimturpuael zugu mew mvlelu fanten
mew. Wvnelu ta inarumeyiñ ta pu registro geohistórico
pegeltulu cumgeci ta wizvmapukunurpukefuy kuyfi
mew ta cegen mapu mew Cile pigelu faciantv; fey mew
kvmeafuy wiñokintuliyiñ feyti mew kuyfi mew rupalu
ka kejuafulu sistemas socio-ecológicos zugu mew ta
kvpaialu. |
| Anxopozeno Cile mew: Ta iñ inazuamfiel ka cumgeci amulerpuael | | Gallardo, L.; Rudnick, A.; Barraza, J.; Fleming, Z.; Rojas, M.; Gayó, E.; Aguirre, C.; Farías, L.; Boisier, J.; Garreaud, R.; Barría, P.; Miranda, A.; Lara, A.; Gómez, S.; Arriagada, R. | 2021 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://bit.ly/3FyHHL0 | | | | | | | Centro de Ciencia del Clima y la Resiliencia mew (CR)2, ta
iñ kvzawkan mew zujiyiñ fey ta nvxamkagelu Anxopozeno
zugu mew ta iñ inarumeael ka ta iñ gvnezuamael. Femgeci
ta cijkatuyiñ cumgeci cambio climático vñfitumapukey
kiñeke mapu mew Cile mew fanten mew, ta iñ kejuael
zugu mew cew ta cijkatugekey ka gvnezuamgekey weke
rvpv ta iñ kvme wimturpuael zugu mew mvlelu fanten
mew. Wvnelu ta inarumeyiñ ta pu registro geohistórico
pegeltulu cumgeci ta wizvmapukunurpukefuy kuyfi
mew ta cegen mapu mew Cile pigelu faciantv; fey mew
kvmeafuy wiñokintuliyiñ feyti mew kuyfi mew rupalu
ka kejuafulu sistemas socio-ecológicos zugu mew ta
kvpaialu. |
| Disentangling the effect of future land use strategies and climate change on streamflow in a mediterranean catchment dominated by tree plantations | Journal of Hydrology | Galleguillos, M.; Gimeno, F.; Puelma, C.; Zambrano-Bigiarini, M.; Lara, A.; Rojas, M. | 2021 | Agua y Extremos; Cambio de Uso de Suelo; Gobernanza e Interfaz Ciencia y Política | 10.1016/j.jhydrol.2021.126047 | https://linkinghub.elsevier.com/retrieve/pii/S0022169421000949 | 126047 | Vol: 595 | 0022-1694 | Thomson Reuters ISI (SCIE) | | English | Climate change (CC) along with Land Use and Land Cover Change (LULCC) have a strong influence in water availability in already fragile Mediterranean ecosystems. In this work the Soil and Water Assessment Tool (SWAT) was implemented for the 2006–2018 period in a rainfed catchment of central Chile (36°) to test the hypothesis that adaptive plantation strategies could mitigate the impacts of climate change and increase streamflow. We also hypothesize that afforestation with exotic tree plantations will reduce water availability in Mediterranean catchments, acting in synergy with climate change. Five LULCC scenarios are analyzed: i) current long-term national Forest Policy (FP), ii) extreme scenario (EX) with large afforestation surfaces, both including the replacement of native shrublands with Pinus radiata; iii) adaptive plantation management scenario (FM), with lower planting density, iv) forced land displacement scenario (FLD), where plantations at the headwaters are moved to lowland areas and replaced with native shrublands, and v) pristine scenario (PR), with only native vegetation. Each LULCC scenario was run with present climate and with projections of different CMIP5 climate models under the RCP 8.5 scenario for the period 2037–2050, and then compared against simulations based on the present land cover and climate. Simulations with the five LULCC scenarios (FP, EX, FM, FLD and PR) with present climate resulted in variations of −2.5, −17.3, 0, 2.3 and 10.9% on mean annual streamflow (Q), while simulations with the current land cover and CC projections produced a 32.1% decrease in mean annual Q. The joint impact of CC and LULCC leads to changes in mean annual Q ranging from −46.2% (EX) to –23.3% (PR). Afforestation with exotic pines will intensify the reduction in water yield, while conservative scenarios focused on native forests protection and restoration could partially mitigate the effect of CC. We make a strong call to rethink current and future land management strategies to cope with lower water availability in a drier future. © 2021 Elsevier B.V. |
| The South Pacific Pressure Trend Dipole and the Southern Blob | Journal of Climate | Garreaud, R.; Clem, K.; Veloso, J. | 2021 | Agua y Extremos | 10.1175/JCLI-D-20-0886.1 | https://journals.ametsoc.org/view/journals/clim/34/18/JCLI-D-20-0886.1.xml | 7661-7676 | Vol: 34 Issue: 18 | 0894-8755, 1520-0442 | Thomson Reuters ISI (SCIE) | | English | During the last four decades, the sea level pressure has been decreasing over the Amundsen–Bellingshausen Sea (ABS) region and increasing between 30° and 40°S from New Zealand to Chile, thus forming a pressure trend dipole across the South Pacific. The trends are strongest in austral winter and have influenced the climate of West Antarctica and South America. The pressure trends have been attributed to decadal variability in the tropics, expansion of the Hadley cell, and an associated positive trend of the southern annular mode, but these mechanisms explain only about half of the pressure trend dipole intensity. Experiments conducted with two atmospheric models indicate that upper ocean warming over the subtropical southwest Pacific (SSWP), termed the Southern Blob, accounts for about half of the negative pressure trend in the ABS region and nearly all the ridging/drying over the eastern subtropical South Pacific, thus contributing to the central Chile megadrought. The SSWP warming intensifies the pressure trend dipole through warming the troposphere across the subtropical South Pacific and shifting the midlatitude storm track poleward into the ABS. Multidecadal periods of strong SSWP warming also appear in fully coupled preindustrial simulations, associated with a pressure trend dipole and reduction in rainfall over the central tropical Pacific, thus suggesting a natural origin of the Southern Blob and its teleconnection. However, the current warming rate exceeds the range of natural variability, implying a likely additional anthropogenic contribution. |
| Seasonal precipitation in South Central Chile: trends in extreme events since 1900 | Atmósfera | González-Reyes, Á.; Jacques-Coper, M.; Muñoz, A. | 2021 | Agua y Extremos; Zonas Costeras | 10.20937/ATM.52871 | https://www.revistascca.unam.mx/atm/index.php/atm/article/view/52871 | 371-384 | Vol: 34 Issue: 4 | | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access; Hybrid Gold Open Access | English | We study a regional precipitation time series, built upon seven meteorological records from South Central Chile (SCC; 37° - 42°S), which together cover the period 1900 - 2019. As a first objective, we investigated changes in the return period (RP) of dry ( P80) seasonal extreme events of precipitation (SEE), for each season. We observed a reduction in the RP of wet SEE during 1900 - 1950 in all seasons. Contrarily, the dry SEE RP shows a reduction from 1950 to the present in all seasons. This phenomenon is noteworthy since 1900 for summer and winter, and since 1930 for autumn. Spring registers a constant RP value from 1990 onwards. As a second objective, we study possible relationships between seasonal precipitation variability and climate modes, such as the Southern Annular Mode (SAM) and the Tripolar Index (TPI) of sea surface temperature (SST) over the Pacific Ocean. Summer and autumn precipitation register a significant negative correlation with SAM activity at interannual and decadal scales, while winter and spring precipitation show a significant positive correlation with SST variability over multiple regions of the Pacific Ocean (including the tropics and New Zealand) and the Southern Ocean (Amundsen-Bellingshausen Sea). Finally, we confirm that SAM strongly modulates precipitation in SCC, especially in autumn, and that SEE variability in SCC is considerably characterized by climate modes of tropical and extra-tropical origin. |
| Leaf Thermal and Chemical Properties as Natural Drivers of Plant Flammability of Native and Exotic Tree Species of the Valparaíso Region, Chile | International Journal of Environmental Research and Public Health | Guerrero, F.; Hernández, C.; Toledo, M.; Espinoza, L.; Carrasco, Y.; Arriagada, A.; Muñoz, A.; Taborga, L.; Bergmann, J.; Carmona, C. | 2021 | Agua y Extremos | 10.3390/ijerph18137191 | https://www.mdpi.com/1660-4601/18/13/7191 | 7191 | Vol: 18 Issue: 13 | 1660-4601 | Thomson Reuters ISI (ESCI) | All Open Access; Gold Open Access | English | Forest fires are one of the main environmental threats in Chile. Fires in this Mediterranean climate region frequently affect native forests and exotic plantations, including in several cases urban and rural settlements. Considering the scarcity of information regarding the fire response dynamics of tree species that are frequently affected by fires, this study aims to establish a flammability classification according to the evolution of the fire initiation risk presented by the most affected forest species in the Valparaíso region. Three exotic species, Eucalyptus globulus, Pinus radiata, and Acacia dealbata, and two native species, Cryptocarya alba and Quillaja saponaria, were studied. Flammability assays indicate that E. globulus, A. dealbata, and C. alba are extremely flammable, whereas P. radiata and Q. saponaria are flammable. Furthermore, E. globulus and A. dealbata have the highest heating values while Q. saponaria has the lowest values. The extreme flammability of E. globulus, A. dealbata, and C. alba indicates a high susceptibility to ignite. Furthermore, the high heat of combustion of E. globulus and A. dealbata can be associated with a high energy release, increasing the risk of fires spreading. In contrast, Q. saponaria has the lowest predisposition to ignite and capacity to release heat. Accordingly, this work shows that all studied tree species contain organic metabolites that are potentially flammable (sesquiterpenes, aliphatic hydrocarbons, alcohol esters, ketones, diterpenes, and triterpenes) and can be considered as drivers of flammability in vegetation. Finally, these preliminary results will aid in the construction of more resilient landscapes in the near future. |
| The last glacial termination in northwestern Patagonia viewed from the Lago Fonk (∼40°S) record | Quaternary Science Reviews | Henríquez, C.; Moreno, P.; Dunbar, R.; Mucciarone, D. | 2021 | Agua y Extremos | 10.1016/j.quascirev.2021.107197 | https://linkinghub.elsevier.com/retrieve/pii/S0277379121004042 | 107197 | Vol: 271 | 02773791 | Thomson Reuters ISI (SCIE) | | English | The anatomy of the Last Glacial Termination (T1) in the southern mid-latitudes, and its relationship with changes in the Southern Westerly Winds (SWW), offers empirical constraints for understanding the mechanisms involved in the transition from the Last Glacial Maximum into the current interglacial. Northwestern Patagonia (40°-44°S) is a sensitive region for monitoring past changes in the SWW, the Patagonian Ice Sheet, terrestrial ecosystems, and fire regimes through T1. Here we present results from Lago Fonk (∼40°S) to examine the structure of T1 based on the palynological, macroscopic charcoal, elemental, and isotopic composition of organic lake sediments. We observe an instantaneous establishment of Nothofagus-dominated forests at the onset of T1, followed by a diversification and densification trend that culminated with the establishment of thermophilous, Myrtaceae-dominated North Patagonian rainforests between ∼15.6–14.7 cal ka BP. The expansion of the conifer Podocarpus nubigena marks a shift to cool-temperate and hyperhumid conditions, coeval with high lake levels and enhanced algal productivity between ∼14.7–11.9 cal ka BP. Stand-replacing fires, driven by enhanced seasonality or high-frequency rainfall variability, started at ∼12.4 cal ka BP and catalyzed the rapid spread of Weinmannia trichosperma. Subsequent warming and a decline in precipitation at ∼11.4 cal ka BP led to intense fire activity, lake-level lowering, and establishment of the Valdivian rainforest trees Eucryphia/Caldcluvia. Our results suggest a coherent linkage between changes documented in the amphi south Pacific region and Antarctic ice cores during T1. This implies a zonal and hemispheric response to changes in the position/intensity of the SWW that emphasizes their central role as a key driver of the hemispheric and global climate evolution through T1. |
| The role of climate and disturbance regimes upon temperate rainforests during the Holocene: A stratigraphic perspective from Lago Fonk (∼40°S), northwestern Patagonia | Quaternary Science Reviews | Henríquez, C.; Moreno, P.; Lambert, F.; Alloway, B. | 2021 | Agua y Extremos; Ciudades Resilientes | 10.1016/j.quascirev.2021.106890 | https://linkinghub.elsevier.com/retrieve/pii/S0277379121000974 | 106890 | Vol: 258 | 02773791 | Thomson Reuters ISI (SCIE) | | English | Climate and disturbance regimes play key roles in shaping the structure, composition and functioning of terrestrial ecosystems. Despite this importance, very few stratigraphic studies in the temperate rainforests from northwestern Patagonia have explored this relationship in detail along a time continuum through the entire Holocene. Here we present a high-resolution fossil pollen and charcoal record from Lago Fonk (median resolution: 20 years), a small closed-basin lake in the lowlands of the Chilean Lake District (41°S), where wildfires and explosive volcanism have intermittently taken place during the Holocene, along with pronounced human-induced disturbance in post-colonial time. Our results show persistence of temperate rainforest throughout the Holocene, with changes in the composition and structure of Valdivian rainforests (VRF) at millennial timescales. We detect centennial-scale alternations in dominance between the VRF tree Eucryphia/Caldcluvia and generalist trees found in VRF and North Patagonian rainforests after ∼6.5 cal ka BP. Intervals dominated by VRF coincide with enhanced fire occurrence signaling negative hydroclimate anomalies with a mean duration of ∼150 years, which alternate with positive hydroclimate anomalies lasting ∼312 years on average.
Our results suggest that the magnitude and rapidity of vegetation changes detected at 10.2–9.9, 4.0–3.0, ∼1.0, and ∼0.7 cal ka BP were amplified by disturbance regimes, and led to the establishment and maintenance of Eucryphia/Caldcluvia-dominated forests in the Longitudinal Valley of the Chilean Lake District. On several occasions the higher incidence of fire disturbance during warm/dry climate intervals coincided with episodes of heightened explosive volcanic activity from multiple eruptive centers within the Southern Andean Volcanic Zone. |
| Diversifying Chile’s climate action away from industrial plantations | Environmental Science & Policy | Hoyos-Santillan, J.; Miranda, A.; Lara, A.; Sepulveda-Jauregui, A.; Zamorano-Elgueta, C.; Gómez-González, S.; Vásquez-Lavín, F.; Garreaud, R.; Rojas, M. | 2021 | Agua y Extremos; Cambio de Uso de Suelo; Gobernanza e Interfaz Ciencia y Política | 10.1016/j.envsci.2021.06.013 | https://linkinghub.elsevier.com/retrieve/pii/S1462901121001738 | 85-89 | Vol: 124 | 14629011 | Thomson Reuters ISI (SCIE) | | English | As president of the Climate Change Conference of the Parties, Chile has advocated for developing ambitious
commitments to mitigate greenhouse gas emissions to achieve carbon-neutrality by 2050. However, Chile’s
motivations and ambitious push to reach carbon-neutrality are complicated by a backdrop of severe drought,
climate change impacts (i.e., wildfires, tree mortality), and the use of industrial plantations as a mitigation
strategy. This has become more evident as widespread and severe wildfires have impacted large areas of industrial plantations, transforming the land-use, land-use change, and forestry sector from a carbon sink to a net
carbon source. Consequently, Chile must diversify its climate actions to achieve carbon-neutrality. Nature-based
solutions, including wetlands-peatlands and oceans, represent alternative climate actions that can be implemented to tackle greenhouse gas emissions at a national level. Diversification, however, must guarantee Chile’s
long-term carbon sequestration capacity without compromising the ecological functionality of biodiverse treeless habitats and native forest ecosystems. |
| The 2019 Southern Hemisphere Stratospheric Polar Vortex Weakening and Its Impacts | Bulletin of the American Meteorological Society | Lim, E.; Hendon, H.; Butler, A.; Thompson, D.; Lawrence, Z.; Scaife, A.; Shepherd, T.; Polichtchouk, I.; Nakamura, H.; Kobayashi, C.; Comer, R.; Coy, L.; Dowdy, A.; Garreaud, R.; Newman, P.; Wang, G. | 2021 | Agua y Extremos | 10.1175/BAMS-D-20-0112.1 | https://journals.ametsoc.org/view/journals/bams/102/6/BAMS-D-20-0112.1.xml | E1150-E1171 | Vol: 102 Issue: 6 | 0003-0007, 1520-0477 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Abstract
This study offers an overview of the low-frequency (i.e., monthly to seasonal) evolution, dynamics, predictability, and surface impacts of a rare Southern Hemisphere (SH) stratospheric warming that occurred in austral spring 2019. Between late August and mid-September 2019, the stratospheric circumpolar westerly jet weakened rapidly, and Antarctic stratospheric temperatures rose dramatically. The deceleration of the vortex at 10 hPa was as drastic as that of the first-ever-observed major sudden stratospheric warming in the SH during 2002, while the mean Antarctic warming over the course of spring 2019 broke the previous record of 2002 by ∼50% in the midstratosphere. This event was preceded by a poleward shift of the SH polar night jet in the uppermost stratosphere in early winter, which was then followed by record-strong planetary wave-1 activity propagating upward from the troposphere in August that acted to dramatically weaken the polar vortex throughout the depth of the stratosphere. The weakened vortex winds and elevated temperatures moved downward to the surface from mid-October to December, promoting a record strong swing of the southern annular mode (SAM) to its negative phase. This record-negative SAM appeared to be a primary driver of the extreme hot and dry conditions over subtropical eastern Australia that accompanied the severe wildfires that occurred in late spring 2019. State-of-the-art dynamical seasonal forecast systems skillfully predicted the significant vortex weakening of spring 2019 and subsequent development of negative SAM from as early as late July. |
| Tree growth decline as a response to projected climate change in the 21st century in Mediterranean mountain forests of Chile | Global and Planetary Change | Matskovsky, V.; Venegas-González, A.; Garreaud, R.; Roig, F.; Gutiérrez, A.; Muñoz, A.; Le Quesne, C.; Klock, K.; Canales, C. | 2021 | Agua y Extremos | 10.1016/j.gloplacha.2020.103406 | https://www.sciencedirect.com/science/article/abs/pii/S0921818120302976 | 13 | Vol: 198 | 0921-8181 | Thomson Reuters ISI (SCIE) | | English | Global Climate Models project that observed climate trends are likely to be preserved and the number of extreme events will be increasing during the rest of the 21st century, which may have a detrimental impact on forest ecosystems. These impacts may include forest decline and widespread dieback of the most vulnerable biomes, such as the Mediterranean Forest of Central Chile (MFCC). Nothofagus macrocarpa and Austrocedrus chilensis are two canopy-dominant, endangered tree species in the mountains of MFCC. Here, we project tree growth of these species based on tree-ring width chronologies, a simplified version of a process-based model, and climate change projections. We used the tree ring information derived from ~400 trees from 12 sites distributed across MFCC in combination with the simplified version of process-based Vaganov-Shashkin tree-growth model (VS-Lite) to forecast changes in tree growth for the next four decades. Tree growth projections were made on the basis of monthly values of temperature and precipitation from the output of 35 climate models based on two ensembles of CO2 emission scenarios of the IPCC AR5 (RCP 8.5: higher-emission scenario, and RCP 2.6: lower-emission scenario). For the MFCC region these scenarios result in temperature rise ranging between 0.5 ◦C and 2.0 ◦C, and a precipitation decrease between 5% and 20% by the year 2065, as related to historical conditions. Our results showed that the VS-Lite model is capable of reproducing tree growth decline during the recent extreme dry period, i.e. 2010–2018, which supports its use for tree growth projections in the MFCC region. According to the modeling results, we find that tree growth in both N. macrocarpa and A. chilensis forests distributed in the MFCC region will be adversely affected by future climate changes, mainly starting from the year 2035, under both scenarios. Our work provides evidence of the degree of vulnerability of Mediterranean mountain forests in central Chile according to current climate change projections. The projected decline in tree growth indicates serious risks in the dynamics and survival of these forests relatively soon, so alerts are given about this situation which may require to counteract the deleterious effects of global change on vegetation in this region. |
| How well do gridded precipitation and actual evapotranspiration products represent the key water balance components in the Nile Basin? | Journal of Hydrology: Regional Studies | McNamara, I.; Baez-Villanueva, O.; Zomorodian, A.; Ayyad, S.; Zambrano-Bigiarini, M.; Zaroug, M.; Mersha, A.; Nauditt, A.; Mbuliro, M.; Wamala, S.; Ribbe, L. | 2021 | Agua y Extremos | 10.1016/j.ejrh.2021.100884 | https://linkinghub.elsevier.com/retrieve/pii/S2214581821001130 | 100884 | Vol: 37 | 22145818 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Study region: Nile Basin, Africa. Study focus: The accurate representation of precipitation (P) and actual evapotranspiration (ETa) patterns is crucial for water resources management, yet there remains a high spatial and temporal variability among gridded products, particularly over data-scarce regions. We evaluated the performance of eleven state-of-the-art P products and seven ETa products over the Nile Basin using a four-step procedure: (i) P products were evaluated at the monthly scale through a point-to-pixel approach; (ii) streamflow was modelled using the Random Forest machine learning technique, and simulated for well-performing catchments for 2009–2018 (to correspond with ETa product availability); (iii) ETa products were evaluated at the multiannual scale using the water balance method; and (iv) the ability of the best-performing P and ETa products to represent monthly variations in terrestrial water storage (ΔTWS) was assessed through a comparison with GRACE Level-3 data. New hydrological insights for the region: CHIRPSv2 was the best-performing P product (median monthly KGE’ of 0.80) and PMLv2 and WaPORv2.1 the best-performing ETa products over the majority of the evaluated catchments. The application of the water balance using these best-performing products captures the seasonality of ΔTWS well over the White Nile Basin, but overestimates seasonality over the Blue Nile Basin. Our study demonstrates how gridded P and ETa products can be evaluated over extremely data-scarce conditions using an easily transferable methodology. |
| Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central Chile | Fire | McWethy, D.; Garreaud, R.; Holz, A.; Pederson, G. | 2021 | Agua y Extremos | 10.3390/fire4020028 | https://www.mdpi.com/2571-6255/4/2/28 | 28 | Vol: 4 Issue: 2 | 2571-6255 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The unprecedented size of the 2017 wildfires that burned nearly 600,000 hectares of central Chile highlight a need to better understand the climatic conditions under which large fires develop. Here we evaluate synoptic atmospheric conditions at the surface and free troposphere associated with anomalously high (active) versus low (inactive) months of area burned in south-central Chile (ca. 32–41° S) from the Chilean Forest Service (CONAF) record of area burned from 1984–2018. Active fire months are correlated with warm surface temperatures, dry conditions, and the presence of a circumpolar assemblage of high-pressure systems located ca. 40°–60° S. Additionally, warm surface temperatures associated with active fire months are linked to reduced strength of cool, onshore westerly winds and an increase in warm, downslope Andean Cordillera easterly winds. Episodic warm downslope winds and easterly wind anomalies superimposed on long-term warming and drying trends will continue to create conditions that promote large fires in south-central Chile. Identifying the mechanisms responsible for easterly wind anomalies and determining whether this trend is strengthening due to synoptic-scale climatic changes such as the poleward shift in Southern Hemisphere westerly winds will be critical for anticipating future large fire activity in south-central Chile. |
| Encuesta sobre percepciones de la ciudadanía de Punta Arenas sobre cambio climático, gobernanza climática y aspectos constitucionales. | | Moraga, P.; Sapiain, R.; Aldunce, P.; Urquiza, A.; Rojas, M.; Medina, L.; Valenzuela, C.; Cornejo, C. | 2021 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política | | https://bit.ly/3pxYatd | | | | | | | Entre agosto 202 y septiembre 2021, un equipo interdisciplinario de la Universidad de Chile, del Centro de Ciencia del Clima y la Resiliencia (CR)2 y con el apoyo del Centro de Investigación GAIA Antártica (CIGA) de la Universidad de Magallanes, desarrolló el proyecto "Laboratorio social para la cosntrucción comunitaria de bases constitucionales para una sociedad resiliente al cambio climático, una perspectiva desde la Patagonia". |
| La ciudad del mañana en la nueva constitución: Una mirada desde la Patagonia | | Moraga, P.; Sapiains A., R.; Rojas, M.; Medina, L.; Valenzuela, C.; Cornejo, C.; Pulgar, A.; Aldunce, P.; Urquiza, A.; Azócar, G.; Sepúlveda, B. | 2021 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política | | https://www.cr2.cl/la-ciudad-del-manana-en-la-nueva-constitucion-una-mirada-desde-la-patagonia/ | | | | | | | Entre agosto 202 y septiembre 2021, un equipo interdisciplinario de la Universidad de Chile, del Centro de Ciencia del Clima y la Resiliencia (CR)2 y con el apoyo del Centro de Investigación GAIA Antártica (CIGA) de la Universidad de Magallanes, desarrolló el proyecto "Laboratorio social para la cosntrucción comunitaria de bases constitucionales para una sociedad resiliente al cambio climático, una perspectiva desde la Patagonia". |
| An early Holocene westerly minimum in the southern mid-latitudes | Quaternary Science Reviews | Moreno, P.; Henríquez, W.; Pesce, O.; Henríquez, C.; Fletcher, M.; Garreaud, R.; Villa-Martínez, R. | 2021 | Agua y Extremos | 10.1016/j.quascirev.2020.106730 | https://linkinghub.elsevier.com/retrieve/pii/S0277379120306922 | 106730 | Vol: 251 Issue: 1 | 0277-3791 | Thomson Reuters ISI (SCIE) | | English | An important coupled ocean-atmospheric system in the mid- and high latitudes involves the Southern Westerly Winds (SWW) and the Southern Ocean (SO), which controls climate in the southernmost third of the world, deep water formation, and ventilation of CO2 from the deep ocean. Most studies have examined its role as a driver of atmospheric CO2 concentrations during glacial terminations, but very few have investigated its influence during the Holocene, i.e. the current interglacial. A fundamental problem, however, is resolving whether the SWW strength increased or declined during the early Holocene (∼11.5–7.5 ka, ka = 1000 cal yr BP) in sectors adjacent to the Drake Passage. Here we assess past changes in SWW influence over the last ∼17,000 years using terrestrial paleoclimate records from southwestern Patagonia (∼52°S). We detect a zonally symmetric Early Holocene Westerly Minimum which diminished wind stress and upwelling on the SO, contributing to a contemporary decline in atmospheric CO2 concentrations and enrichment in the stable carbon isotope ratio of atmospheric CO2 (δ13Catm). Our mid-latitude data also indicate a shift to strong SWW influence at ∼7.5 ka which correlates with a sustained increase in atmospheric CO2 and halt in the δ13Catm rise, suggesting enhancement of high-latitude ocean ventilation by an invigorated SWW-SO coupled system. |
| Vegetation, disturbance, and climate history since the onset of ice-free conditions in the Lago Rosselot sector of Chiloé continental (44°S), northwestern Patagonia | Quaternary Science Reviews | Moreno, P.; Videla, J.; Kaffman, M.; Henríquez, C.; Sagredo, E.; Jara-Arancio, P.; Alloway, B. | 2021 | Agua y Extremos | 10.1016/j.quascirev.2021.106924 | https://linkinghub.elsevier.com/retrieve/pii/S0277379121001311 | 106924 | Vol: 260 | 02773791 | Thomson Reuters ISI (SCIE) | | English | We present results from Lago Negro, a small closed-basin lake adjacent to Lago Rosselot, to examine the vegetation and environmental history of an insufficiently studied sector of Chiloé Continental (41°30′-44°S) in northwestern Patagonia. Lake sediment cores from Lago Negro reveal 27 tephra deposited since ∼12.7 ka, including two prominent rhyodacite tephra marker beds erupted from Volcán Melimoyu, and a stratified basal clastic unit we attribute to meltwater discharge from an ice tongue that originated from Monte Queulat and covered Lago Rosselot during its expanded position, presumably Antarctic Cold Reversal in age. The pollen record shows closed-canopy North Patagonian rainforests since ∼12.7 ka, with variations in species composition and structure that suggest dynamic responses of the vegetation to past environmental changes. Vegetation responses to climate in the Lago Negro record were modulated, sometimes interrupted, by high magnitude and frequent disturbance regimes, most notably during maxima in explosive volcanic activity (∼9.5–7.2 ka and ∼3.6–1.6 ka) and heightened fire activity.
Since Lago Negro is the southernmost palynological site so far investigated in the region and is located within a volcanically active sector, it provides a valuable perspective for assessing past vegetation responses along environmental gradients since the last glaciation. When compared with other sites throughout northwestern Patagonia, our record reveals a distinct north-to-south gradient in temperature and precipitation, with peak temperature and rainfall seasonality in the north, and a west-to-east gradient in disturbance regimes, with maximum frequency and magnitude of explosive volcanic events in the east. These gradients have modulated the response of rainforest vegetation to climate forcing at regional scale since ∼12.7 ka. We identify negligible differences in timing for the majority of key vegetation signals during the initial phase of the Lago Negro record, and propose that plant colonization and expansion along the ∼360 km long corridor through the Pacific slope of the northwestern Patagonian Andes was a rapid process during the Last Glacial Termination. |
| Local and global environmental drivers of growth chronologies in a demersal fish in the south-eastern Pacific Ocean | Ecological Indicators | Moyano, G.; Plaza, G.; Cerna, F.; Muñoz, A. | 2021 | Agua y Extremos | 10.1016/j.ecolind.2021.108151 | https://linkinghub.elsevier.com/retrieve/pii/S1470160X21008165 | 108151 | Vol: 131 | 1470-160X | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Upwelling and the El Niño “Southern Oscillation” (ENSO) are recurrent climatic phenomena in the southeastern Pacific Ocean that severely affect the reproduction and growth of pelagic fish populations. However, there are not long-term growth data from demersal fish populations to test these interconections in a long-term analysis. For this reason, a first extensive growth chronology was reconstructed from the annual growth of sagittal otoliths as a proxy for somatic growth for the cardinalfish (Epigonus crassicaudus). Adult fish ranging from 35 to 40 cm in fork length and from 39 to 63 years in age were collected off Chilean waters. The master chronologies were estimated for the period from 1974 to 2014, using the regional curve standardization approach (RCS) and linear mixed models (LMMs). Growth indexes derived from both approaches followed a similar trend and were positively correlated with the Humboldt Current Index (HCI) and negatively with ENSO, Pacific Decadal Oscillation and sea surface temperature. LMMs showed that a 75% of growth variability was explained by the age of increment formation and HCI was the environmental index that most significantly affected the annual growth of cardinalfish followed by the sea surface temperature in spring. A reduced growth phase from 1974 to 1996 contrasted with a higher growth period from 1997, matching the 1997/1998 climatic regime shift, demonstrating that the enhanced growth for cardinalfish was associated with upwelling of nutrient rich water to the surface, triggering an increase of the primary and secondary productivity during the prevalence of a cold regime period in the Humboldt Current System. The consistence between RCS and LMM methods was indicative that both approaches are promising to evaluate the influence of environmental drivers on the growth condition of a demersal fish population in a highly productive marine ecosystem. © 2021 The Author(s) |
| La construcción social de los mercados de agua en Chile: Un enfoque desde la geografía legal | Revista de geografía Norte Grande | Nicolas-Artero, C. | 2021 | Agua y Extremos | 10.4067/S0718-34022021000200163 | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-34022021000200163&lng=en&nrm=iso&tlng=en | 163-182 | Vol: 2021 Issue: 79 | 0718-3402 | Thomson Reuters ISI (SCIE; SSCI) | All Open Access; Gold Open Access; Green Open Access | English | The article proposes an approach from the legal geography to understand the social construction of water markets in the semi-arid basin of the Elqui river, from the second half of the 20th century. Using qualitative methodologies (ethnography, interviews, archives), it reveals the jointly spatial and legal dimension of the formation of water markets. The technical water objects installed since the second half of the 20th century attract new investors and transform the political economy of the valley. Since then, the users have used technical water objects and have instrumentalized or produced law locally to buy, sell or rent water rights, forming five water markets. |
| Introducción. Disputada, apropiada y desposeída: la naturaleza en las ciudades latinoamericanas | Cahiers des Amériques latines | Nicolas-Artero, C.; Fuster-Farfán, X.; Velut, S. | 2021 | Agua y Extremos | 10.4000/cal.13089 | http://journals.openedition.org/cal/13089 | 1-13 | Issue: 97 | 1141-7161, 2268-4247 | Thomson Reuters ISI (ESCI) | All Open Access; Gold Open Access | Spanish | |
| Introduction. Contestée, appropriée et dépossédée : la place de la nature dans les villes latino-américaines | Cahiers des Amériques latines | Nicolas-Artero, C.; Fuster-Farfán, X.; Velut, S. | 2021 | Agua y Extremos | 10.4000/cal.13080 | http://journals.openedition.org/cal/13080 | 23-35 | Issue: 97 | 1141-7161, 2268-4247 | Thomson Reuters ISI (ESCI) | All Open Access; Gold Open Access | French | |
| Oceanography time series reveals annual asynchrony input between oceanic and estuarine waters in Patagonian fjords | Science of The Total Environment | Pérez-Santos, I.; Díaz, P.; Silva, N.; Garreaud, R.; Montero, P.; Henríquez-Castillo, C.; Barrera, F.; Linford, P.; Amaya, C.; Contreras, S.; Aracena, C.; Pinilla, E.; Altamirano, R.; Vallejos, L.; Pavez, J.; Maulen, J. | 2021 | Agua y Extremos | 10.1016/j.scitotenv.2021.149241 | https://linkinghub.elsevier.com/retrieve/pii/S004896972104314X | 149241 | Vol: 798 | 00489697 | Thomson Reuters ISI (SCIE) | | English | The postglacial Patagonian fjord system along the west coast of southern South America is one of the largest stretches of the southern hemisphere (SH) fjord belt, influenced by the SH westerly wind belt and continental freshwater input. This study reports a 3-year monthly time series (2017–2020) of physical and biogeochemical parameters obtained from the Reloncaví Marine Observatory (OMARE, Spanish acronym) at the northernmost embayment and fjord system of Patagonia. The main objective of this work was to understand the land–atmosphere–ocean interactions and to identify the mechanisms that modulate the density of phytoplankton. A key finding of this study was the seasonally varying asynchronous input of oceanic and estuarine water. Surface lower salinity and warmer estuarine water arrived in late winter to summer, contributing to water column stability, followed by subsurface higher salinity and less warmer oceanic water during fall–winter. In late winter 2019, an interannual change above the picnocline due to the record-high polarity of the Indian Ocean Dipole inhibited water column stability. The biogeochemical parameters (NO3−, NO2−, PO43−, Si(OH)4, pH, and dissolved oxygen) responded to the surface annual salinity variations, and oceanic water mass contributed greatly to the subsurface inorganic nutrient input. The water column N/P ratio indicated that no eutrophication occurred, even under intense aquaculture activity, likely because of the high ventilation dynamics of the Reloncaví Sound. Finally, a shift in phytoplankton composition, characterized by surface chlorophyll-a maxima in late winter and deepening of spring–summer blooms related to the physicochemical conditions of the water column, was observed. Our results support the ecosystem services provided by local oceanography processes in the north Patagonian fjords. Here, the anthropogenic impact caused by economic activities could be, in part, chemically reduced by the annual ventilation cycle mediated by the exchange of oceanic water masses into Patagonian fjords. |
| Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana , the world’s highest elevation tree species | Tree Physiology | Rodriguez-Caton, M.; Andreu-Hayles, L.; Morales, M.; Daux, V.; Christie, D.; Coopman, R.; Alvarez, C.; Rao, M.; Aliste, D.; Flores, F.; Villalba, R. | 2021 | Agua y Extremos | 10.1093/treephys/tpab021 | https://academic.oup.com/treephys/article/41/8/1353/6144557 | 1353-1371 | Vol: 41 Issue: 8 | 1758-4469 | Thomson Reuters ISI (SCIE) | | English | Abstract
Tree growth is generally considered to be temperature limited at upper elevation treelines, yet climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polylepis tarapacana Philipi, the world’s highest elevation tree species, which is found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (δ18O) and carbon (δ13C) chronologies for the last 60 years at four P. tarapacana stands located above 4400 m in elevation, along a 500 km latitude aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon sink processes along the gradient. Current growing-season temperature regulated RWI at northern-wetter sites, while prior growing-season precipitation determined RWI at arid southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site water availability. By contrast, warm and dry growing seasons resulted in enriched tree-ring δ13C and δ18O at all study sites, suggesting that similar climate conditions control carbon-source processes along the gradient. Site-level δ13C and δ18O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. This manuscript also highlights a coupling (decoupling) between physiological processes at leaf level and wood formation as a function of similarities (differences) in their climatic sensitivity. This study contributes to a better understanding and prediction of the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano. |
| Assessment of GPM IMERG satellite precipitation estimation and its dependence on microphysical rain regimes over the mountains of south-central Chile | Atmospheric Research | Rojas, Y.; Minder, J.; Campbell, L.; Massmann, A.; Garreaud, R. | 2021 | Agua y Extremos | 10.1016/j.atmosres.2021.105454 | https://linkinghub.elsevier.com/retrieve/pii/S0169809521000065 | 105454 | Vol: 253 | 0169-8095 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Satellite data provide crucial information for those places lacking precipitation observations from ground-based sensors, especially over oceans, mountain regions, or developing countries. This is the case over much of South America, including Chile, a country with complex topography that has limited long-term precipitation records and high-elevation data, and no operational weather radars. This study focuses on investigating the skill of the Global Precipitation Measurement (GPM) Integrated Multi-Satellite Retrieval for GPM (IMERG: version 6) quantitative precipitation estimation (QPE). IMERG is assessed against ground-based observations from two field campaigns that took place near 36°S: The Chilean Coastal Orographic Precipitation Experiment (CCOPE; winter 2015), which collected data over the coastal mountain range, and The Chilean Orographic and Mesoscale Precipitation Study (ChOMPS; winter 2016), which collected observations in a transect from the coast to the Andes. To characterize how IMERG performance depends on microphysical regime, we used data from profiling radars and rain gauge measurements to classify rainfall into regimes including “ice-initiated rain” and “warm rain”, characterized by the presence or absence of a well-defined melting layer respectively. Rain gauge data was used to evaluate performance of IMERG QPE overall and for these two regimes. IMERG depicts the general spatial pattern of observed orographic enhancement but highly underestimates the magnitude of this enhancement. At higher elevations during CCOPE, IMERG underestimated the total amount of rainfall by 50%, while during ChOMPS the underestimation was by 16%. For CCOPE, at higher elevation sites, IMERG underestimated ice-initiated rain by 30% and underestimated warm rain by 70%. For ChOMPS, the underestimation at the Andes site was 33% for ice-initiated rain and 50% for warm rain. IMERG QPE for both field campaigns showed larger underestimations for warm rain periods and at higher elevations than for ice-initiated rain periods. Documenting how IMERG performance varies with terrain and microphysical regime may help guide improvements to satellite-based QPE. |
| Marco teórico de Transformación: Cómo nos transformamos para responder a los crecientes impactos del cambio climático | | Salgado, M.; Aldunce, P. | 2021 | Agua y Extremos | | https://bit.ly/3ISdjNz | 23 | | | | | | El cambio climático es uno de los mayores desafíos que la ha tenido que enfrentar, requiriendo que la sociedad deba responder de manera urgente y colaborativa, con el objetivo de disminuir los crecientes impactos que este fenómeno produce, los que han ido en aumentando tanto en severidad, como en magnitud (IPCC, 2018). |
| The 21st-century fate of the Mocho-Choshuenco ice cap in southern Chile | The Cryosphere | Scheiter, M.; Schaefer, M.; Flández, E.; Bozkurt, D.; Greve, R. | 2021 | Agua y Extremos; Zonas Costeras | 10.5194/tc-15-3637-2021 | https://tc.copernicus.org/articles/15/3637/2021/ | 3637-3654 | Vol: 15 Issue: 8 | 1994-0424 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access; Green Open Access | English | Glaciers and ice caps are thinning and retreating along the entire Andes ridge, and drivers of this mass loss vary between the different climate zones. The southern part of the Andes (Wet Andes) has the highest abundance of glaciers in number and size, and a proper understanding of ice dynamics is important to assess their evolution. In this contribution, we apply the ice-sheet model SICOPOLIS (SImulation COde for POLythermal Ice Sheets) to the Mocho-Choshuenco ice cap in the Chilean Lake District (40∘ S, 72∘ W; Wet Andes) to reproduce its current state and to project its evolution until the end of the 21st century under different global warming scenarios. First, we create a model spin-up using observed surface mass balance data on the south-eastern catchment, extrapolating them to the whole ice cap using an aspect-dependent parameterization. This spin-up is able to reproduce the most important present-day glacier features. Based on the spin-up, we then run the model 80 years into the future, forced by projected surface temperature anomalies from different global climate models under different radiative pathway scenarios to obtain estimates of the ice cap's state by the end of the 21st century. The mean projected ice volume losses are 56±16 % (RCP2.6), 81±6 % (RCP4.5), and 97±2 % (RCP8.5) with respect to the ice volume estimated by radio-echo sounding data from 2013. We estimate the uncertainty of our projections based on the spread of the results when forcing with different global climate models and on the uncertainty associated with the variation of the equilibrium line altitude with temperature change. Considering our results, we project a considerable deglaciation of the Chilean Lake District by the end of the 21st century. |
| Scientific warnings could help to reduce farmed salmon mortality due to harmful algal blooms | Marine Policy | Soto, D.; León-Muñoz, J.; Garreaud, R.; Quiñones, R.; Morey, F. | 2021 | Agua y Extremos | 10.1016/j.marpol.2021.104705 | https://linkinghub.elsevier.com/retrieve/pii/S0308597X2100316X | 104705 | Vol: 132 | 0308597X | Thomson Reuters ISI (SSCI) | | English | The increasing occurrence of harmful algal blooms (HABs) affecting mariculture has been related to climatic factors but also to increasing eutrophication of coastal zones, to which aquaculture may also contribute. The role of climate change on HABs may be increasingly relevant but scientific efforts to separate this from other causal factors are to date inconclusive. HABs have been a permanent threat to the aquaculture industry in southern Chile, yet government and farmers may have not paid enough attention to scientific information and advice, even when risk-based predictions and warnings have been provided. Here we describe eutrophication risk assessments for water bodies hosting salmon farms and climate change risk maps for the salmon industry in Chilean Patagonia, including the increase of HABs as a main threat. Assessments and maps were delivered in 2020 both to producers and to government. We show that such risk information and mapping could have lessened recent salmon mortality due to HABs (March-April 2021) if government and farmers had followed explicit recommendations to reduce salmon farming production in water bodies with higher risk. This measure would reduce Exposure and Sensitivity under the climate change risk framework used. We provide policy recommendations, including reviewing maximum salmon production in relevant water bodies such as fjords according to eutrophication risks, while paying attention to additional stress from climate change variability and trends. |
| The Chilean Tornado Outbreak of May 2019: Synoptic, mesoscale, and historical contexts | Bulletin of the American Meteorological Society | Vicencio, J.; Rondanelli, R.; Campos, D.; Valenzuela, R.; Garreaud, R.; Reyes, A.; Padilla, R.; Abarca, R.; Barahona, C.; Delgado, R.; Nicora, G. | 2021 | Agua y Extremos; Zonas Costeras | 10.1175/BAMS-D-19-0218.1 | https://journals.ametsoc.org/view/journals/bams/aop/BAMS-D-19-0218.1/BAMS-D-19-0218.1.xml | E611-E634 | Vol: 102 Issue: 3 | 0003-0007, 1520-0477 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | In late May 2019, at least seven tornadoes were reported within a 24-h period in southern Chile (western South America, 36°–38°S), including EF1 and EF2 events causing substantial damage to infrastructure, dozens of injuries, and one fatality. Despite anecdotal evidence and chronicles of similar historical events, the threat from tornadoes in Chile was regarded with skepticism until the 2019 outbreak. Herein, we describe the synoptic-scale features instrumental in the development of these tornadic storms, including an extended southwest–northeast trough along the South Pacific, with a large postfrontal instability area. Tornadic storms appear to be embedded in a modestly unstable environment (positive convective available potential energy but less than 1,000 J kg−1) and strong low- and midlevel wind shear, with high near-surface storm-relative helicity values (close to −200 m2 s−2), clearly differing from the Great Plains tornadoes in North America (with highly unstable environments) but resembling cold-season tornadoes previously observed in the midlatitudes of North America, Australia, and Europe. Reanalyzing rainfall and lightning data from the last 10 years, we found that tornadic storms in our region occur associated with locally extreme values of both CAPE and low-level wind shear, where a combination of the two in a low-level vorticity generation parameter appears as a simple first-order discriminant between tornadic and nontornadic environments. Future research should thoroughly examine historical events worldwide to assemble a database of high-shear, low-CAPE midlatitude storms and help improve our understanding of these storms’ underlying physics. |
| Development and resilience of deciduous Nothofagus forests since the Last Glacial Termination and deglaciation of the central Patagonian Andes | Palaeogeography, Palaeoclimatology, Palaeoecology | Villa-Martínez, R.; Moreno, P. | 2021 | Agua y Extremos | 10.1016/j.palaeo.2021.110459 | https://linkinghub.elsevier.com/retrieve/pii/S0031018221002443 | 110459 | Vol: 574 | 00310182 | Thomson Reuters ISI (SCIE) | | English | Resolving the history of vegetation, fire, and glaciation on the eastern slope of the central Patagonian Andes (44°-49°S) since the Last Glacial Termination (T1) has proved difficult. This is due to the steep environmental gradients, vegetation heterogeneity, and scarcity of dated glacial deposits and geomorphic features. Unsurprisingly, published records show important heterogeneities which limit our understanding of the timing and magnitude of climate and vegetation changes, and their driving mechanisms since T1. In this paper, we describe sediment cores from small closed-basin lakes located in the deciduous Nothofagus forest zone near Coyhaique, Chile. Our results indicate that the Coyhaique glacier lobe abandoned its final Last Glacial Maximum position just before ~17.9 cal kyr BP and underwent a step-wise recession that included a halt/readvance that culminated at ~16.8 cal kyr BP, contemporaneous with the formation of an ice-dammed proglacial lake in the Coyhaique/Balmaceda sector. This glacial lake stood at its highest level between ~17.9–17.2 cal kyr BP (<726 and > 650 m.a.s.l.), lowered between ~17.2–16.2 cal kyr BP (<650 and > 570 m.a.s.l.), and disappeared thereafter. Herbs and shrubs, currently dominant in high Andean and Patagonian steppe environments, colonized the ice-free terrains distal to the glacier margins and proglacial lakes under cold and dry conditions. This was followed by a steady increase in Nothofagus between ~16.6–14.8 cal kyr BP that led to the establishment of forests starting at ~14.8 cal kyr BP. The Holocene started with a sudden increase in Nothofagus and disappearance of conifers in the context of increase fire activity between ~11.7–9.4 cal kyr BP. Closed-canopy Nothofagus forests persisted virtually unaltered from ~9.4 cal kyr BP to the present day, despite frequent explosive volcanism and millennial-scale variations in fire regimes, attesting to their extraordinary postglacial resilience which contrasts with their behavior during T1. Recent large-scale deforestation by fire, livestock grazing, and the spread of non-native invasive plant species drove the fastest and largest-magnitude shifts seen during the last ~16,500 years. |
| Informe ¿Sequía o Aridización? ¿Qué haremos para enfrentar esta nueva normalidad? | | Villanueva, L.; Ormazábal, B.; Garreaud, R. | 2021 | Agua y Extremos | | https://bit.ly/3Ewl2O3 | | | | | | | La Sección de Emergencias y Gestión de Riesgos Agrícolas, en su propósito de generar
conciencia y buscar soluciones para abordar los riesgos que afectan recurrentemente a la
agricultura y sus agricultores, busca desarrollar espacios de integración, conversación y
colaboración. Una de estas instancias es el Outlook Estacional,
El encuentro realizado el 12 de mayo, titulado “¿Sequía o aridización? Outlook Estacional
otoño-invierno 2021, reunió a representantes de los distintos sectores del agro, de las
instituciones que otorgan servicios en meteorológica e hidrología, expertos de la academia y
público en general. Su objetivo fue conocer y analizar la situación climática con el fin
de proponer/acordar medidas de adaptación.
El presente documento ha sido elaborado con el fin de dejar un testimonio del desarrollo del
encuentro en su contenido técnico, académico e institucional, incluyendo las opiniones y
aportes de los participantes. Así también, busca relevar la importancia de este tipo de
encuentros para el público de interés, quienes requieren más información, herramientas,
nueva tecnología, integración de los organismos público-privado e instancias participativas
para, en conjunto, buscar/implementar soluciones y así minimizar los impactos de la sequía
que se vienen presentando ya hace una década. |
| Large-sample hydrology: recent progress, guidelines for new datasets and grand challenges | Hydrological Sciences Journal | Addor, N.; Do, H.; Alvarez-Garreton, C.; Coxon, G.; Fowler, K.; Mendoza, P. | 2020 | Agua y Extremos | 10.1080/02626667.2019.1683182 | https://www.tandfonline.com/doi/full/10.1080/02626667.2019.1683182 | 712-725 | Vol: 65 Issue: 5 | 0262-6667, 2150-3435 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | Large-sample hydrology (LSH) relies on data from large sets (tens to thousands) of catchments to go beyond individual case studies and derive robust conclusions on hydrological processes and models. Numerous LSH datasets have recently been released, covering a wide range of regions and relying on increasingly diverse data sources to characterize catchment behaviour. These datasets offer novel opportunities, yet they are also limited by their lack of comparability, uncertainty estimates and characterization of human impacts. This article (i) underscores the key role of LSH datasets in hydrological studies, (ii) provides a review of currently available LSH datasets, (iii) highlights current limitations of LSH datasets and (iv) proposes guidelines and coordinated actions to overcome these limitations. These guidelines and actions aim to standardize and automatize the creation of LSH datasets worldwide, and to enhance the reproducibility and comparability of hydrological studies. |
| A Network for Advancing Dendrochronology, Dendrochemistry and Dendrohydrology in South America | Tree-Ring Research | Aguilera-Betti, I.; Lucas, C.; Ferrero, M.; Muñoz, A. | 2020 | Agua y Extremos | 10.3959/TRR2019-12 | https://bioone.org/journals/tree-ring-research/volume-76/issue-2/TRR2019-12/A-Network-for-Advancing-Dendrochronology-Dendrochemistry-and-Dendrohydrology-in-South/10.3959/TRR2019-12.full | 94 | Vol: 76 Issue: 2 | 1536-1098 | Thomson Reuters ISI (SCIE) | | English | Tree-ring research (TRR) in South America (SA) continues to make important contributions in multiple sub-disciplines, including dendrochemistry and dendrohydrology. 1 2 communicate recent advances in TRR within a network of laboratories in Argentina, Brazil, Chile, Peru, and Uruguay. Novel methodologies and results in dendrochemistry and wood anatomy were also presented by collaborating researchers from German institutions. The report describes some of the research within the subdisciplines of tree-ring science, including dendrochemistry, anatomy and dendrohydrology, and their application to understanding spatio-temporal variability in heavy metal contamination, climate, hydrology, fire regimes and other critical components of South American forest and woodland ecosystems. The meeting demonstrated a broadening and diversification in the research and applications of TRR in SA, whereby collaboration across research centers has been critical for the advances made in broad-scale comparative studies as well as multi-proxy approaches and the study of global and hemisphere-scale climate phenomena. |
| Informe de devolución Valle del Aconcagua: Percepción y prácticas de adaptación. Segunda Parte: cambio climático, lluvias extremas y aumento de la temperatura (segunda edición) | | Aldunce, P.; Sapiains, R.; Fuentes, C.; Marchant, G.; Moreau, A.; Velden, F.; Ugarte, A. | 2020 | Agua y Extremos | | https://www.cr2.cl/wp-content/uploads/2020/10/Aconcagua_2020.pdf | 1-16 | | | | | | El cambio climático es uno de los mayores desafíos
que enfrenta la sociedad actual. El Valle de Aconcagua, ubicado en la Región de Valparaíso, no es ajeno
a esta situación y donde se presentan desafíos que
necesitan de un trabajo permanente, comprometido
e informado por parte de todos los actores del territorio, para asegurar el bienestar presente y futuro.
El presente documento resume los resultados del trabajo realizado con distintos actores sociales del Valle
de Aconcagua, entre los años 2015 a 2018, respecto
de lo que significa el cambio climático para ellos, los
impactos que han experimentado, y las estrategias y
prácticas que han desarrollado para enfrentarlo.
Lo aquí presentado contribuye a la reflexión sobre
qué podemos hacer para fortalecer las prácticas de
adaptación y aumentar las capacidades para anticiparse, resistir y recuperarse de los efectos del cambio
climático de manera oportuna y eficaz. |
| ARCLIM Anexo: Piloto Riesgo integrado de Asentamientos Huanos. Conurbación Valparaíso - Viña del Mar | | Amigo, C.; Alamos, N.; Arrieta, D.; Billi, M.; Contreras, M.; Larragubel, C.; Muñoz, A.; Smith, P.; Urquiza, A.; Vargas, M.; Videla, J.; Winckler, P. | 2020 | Agua y Extremos; Ciudades Resilientes | | | | | | | | | |
| Extreme Drought Affects Visitation and Seed Set in a Plant Species in the Central Chilean Andes Heavily Dependent on Hummingbird Pollination | Plants | Arroyo, M.; Robles, V.; Tamburrino, Í.; Martínez-Harms, J.; Garreaud, R.; Jara-Arancio, P.; Pliscoff, P.; Copier, A.; Arenas, J.; Keymer, J.; Castro, K. | 2020 | Agua y Extremos | 10.3390/plants9111553 | https://www.mdpi.com/2223-7747/9/11/1553 | 1553 | Vol: 9 Issue: 11 | 2223-7747 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Rising temperatures and increasing drought in Mediterranean-type climate areas are expected to affect plant–pollinator interactions, especially in plant species with specialised pollination. Central Chile experienced a mega drought between 2010 and 2020 which reached an extreme in the austral summer of 2019–2020. Based on intensive pollinator sampling and floral studies we show that the subalpine form of Mutisia subulata (Asteraceae) is a specialised hummingbird-pollinated species. In a two-year study which included the severest drought year, we quantified visitation frequency, flower-head density, flower-head visitation rates, two measures of floral longevity, nectar characteristics and seed set and monitored climatic variables to detect direct and indirect climate-related effects on pollinator visitation. Flower-head density, nectar standing crop and seed set were significantly reduced in the severest drought year while nectar concentration increased. The best model to explain visitation frequency included flower-head density, relative humidity, temperature, and nectar standing crop with highly significant effects of the first three variables. Results for flower-head density suggest hummingbirds were able to associate visual signals with reduced resource availability and/or were less abundant. The negative effect of lower relative humidity suggests the birds were able to perceive differences in nectar concentration. Reduced seed set per flower-head together with the availability of far fewer ovules in the 2019–2020 austral summer would have resulted in a major reduction in seed set. Longer and more intense droughts in this century could threaten local population persistence in M. subulata. |
| RF-MEP: A novel Random Forest method for merging gridded precipitation products and ground-based measurements | Remote Sensing of Environment | Baez-Villanueva, O.; Zambrano-Bigiarini, M.; Beck, H.; McNamara, I.; Ribbe, L.; Nauditt, A.; Birkel, C.; Verbist, K.; Giraldo-Osorio, J.; Xuan Thinh, N. | 2020 | Agua y Extremos | 10.1016/j.rse.2019.111606 | https://linkinghub.elsevier.com/retrieve/pii/S0034425719306261 | 111606 | Vol: 239 | 00344257 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | The accurate representation of spatio-temporal patterns of precipitation is an essential input for numerous environmental applications. However, the estimation of precipitation patterns derived solely from rain gauges is subject to large uncertainties. We present the Random Forest based MErging Procedure (RF-MEP), which combines information from ground-based measurements, state-of-the-art precipitation products, and topography-related features to improve the representation of the spatio-temporal distribution of precipitation, especially in data-scarce regions. RF-MEP is applied over Chile for 2000—2016, using daily measurements from 258 rain gauges for model training and 111 stations for validation. Two merged datasets were computed: RF-MEP3P (based on PERSIANN-CDR, ERA-Interim, and CHIRPSv2) and RF-MEP5P (which additionally includes CMORPHv1 and TRMM 3B42v7). The performances of the two merged products and those used in their computation were compared against MSWEPv2.2, which is a state-of-the-art global merged product. A validation using ground-based measurements was applied at different temporal scales using both continuous and categorical indices of performance. RF-MEP3P and RF-MEP5P outperformed all the precipitation datasets used in their computation, the products derived using other merging techniques, and generally outperformed MSWEPv2.2. The merged P products showed improvements in the linear correlation, bias, and variability of precipitation at different temporal scales, as well as in the probability of detection, the false alarm ratio, the frequency bias, and the critical success index for different precipitation intensities. RF-MEP performed well even when the training dataset was reduced to 10% of the available rain gauges. Our results suggest that RF-MEP could be successfully applied to any other region and to correct other climatological variables, assuming that ground-based data are available. An R package to implement RF-MEP is freely available online at https://github.com/hzambran/RFmerge. |
| Bias correction of global high-resolution precipitation climatologies using streamflow observations from 9372 catchments | Journal of Climate | Beck, H.; Wood, E.; McVicar, T.; Zambrano-Bigiarini, M.; Alvarez-Garreton, C.; Baez-Villanueva, O.; Sheffield, J.; Karger, D. | 2020 | Agua y Extremos | 10.1175/JCLI-D-19-0332.1 | http://journals.ametsoc.org/doi/10.1175/JCLI-D-19-0332.1 | 1299-1315 | Vol: 33 Issue: 4 | 0894-8755 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | We introduce a set of global high-resolution (0.05
◦
) precipitation ( P) climatologies corrected for bias using streamflow ( Q) observations from 9372 stations worldwide. For each station, we inferred the “true” long-term P using a Budyko curve, an empirical equation relating long-term P, Q, and potential evaporation. We subsequently calculated long-term bias correction factors for three state-of-the-art P climatologies (WorldClim V2, CHELSA V1.2, and CHPclim V1), after which we used random forest regression to produce global gap-free bias correction maps for the climatologies. Monthly climatological bias correction factors were calculated by disaggregating the long-term bias correction factors based on gauge catch efficiencies. We found that all three climatologies systematically underestimate P over parts of all major mountain ranges globally, despite the explicit consideration of orography in the production of each climatology. Additionally, all climatologies underestimate P at latitudes > 60
◦
N, likely due to gauge under-catch. Exceptionally high long-term correction factors ( > 1 .5) were obtained for all three climatologies in Alaska, High Mountain Asia, and Chile — regions characterized by marked elevation gradients, sparse gauge networks, and significant snowfall. Using the bias-corrected WorldClim V2, we demonstrated that other widely used P datasets (GPCC V2015, GPCP V2.3, and MERRA-2) severely underestimate P over Chile, the Himalayas, and along the Pacific coast of North America. Mean P for the global land surface based on the bias-corrected WorldClim V2 is 862 mm yr
−1
(a 9.4 % increase over the original WorldClim V2). The annual and monthly bias-corrected P climatologies have been released as the Precipitation Bias CORrection (PBCOR) dataset — downloadable via www.gloh2o.org/pbcor . |
| Hydrological Processes Special Issue “Hydrological processes across climatic and geomorphological gradients of Latin America” | Hydrological Processes | Birkel, C.; Moore, G.; Zambrano‐Bigiarini, M. | 2020 | Agua y Extremos | 10.1002/hyp.13648 | https://onlinelibrary.wiley.com/doi/abs/10.1002/hyp.13648 | 156-158 | Vol: 34 Issue: 2 | 0885-6087, 1099-1085 | Thomson Reuters ISI (SCIE) | | English | In this special issue of Hydrological Processes, we showcase the variety of ongoing research in catchments of the hydrometeorological, geomorphological, and biogeographical megadiverse region of Latin America and the Caribbean (LAC). The papers of this special issue address hydrological processes that regulate storage, mixing, and fluxes of water and solutes from the driest Atacama Desert in Chile (annual precipitation lower than 10 mm in some places) to the wettest mountainous areas of Central America (annual rainfall up to 8,000 mm), including the richest biodiversity on Earth present in the Amazon. Not only are tropical rainforest ecosystems poorly represented in hydrologic research, the LAC contains a myriad of unique lowland to montane ecosystems across the climate gradient that also includes snow and ice processes. Opportunities to advance understanding of how vegetation and landforms redistribute moisture abound in the remote reaches of Latin America. Such modulation of the hydrological cycle by vegetation and large‐scale connecting driving forces of rainfall generating moisture transport is the topic of the contributions briefly introduced in the following section.
There are three major transcending themes covered in this special issue:
1) hydrological processes across climate gradients,
2) unique ecosystems with limited hydrological research,
3) effects of land use change on hydrology. |
| Recent Near-surface Temperature Trends in the Antarctic Peninsula from Observed, Reanalysis and Regional Climate Model Data | Advances in Atmospheric Sciences | Bozkurt, D.; Bromwich, D.; Carrasco, J.; Hines, K.; Maureira, J.; Rondanelli, R. | 2020 | Agua y Extremos; Zonas Costeras | 10.1007/s00376-020-9183-x | http://link.springer.com/10.1007/s00376-020-9183-x | 477-493 | Vol: 37 Issue: 5 | 0256-1530, 1861-9533 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | This study investigates the recent near-surface temperature trends over the Antarctic Peninsula. We make use of available surface observations, ECMWF’s ERA5 and its predecessor ERA-Interim, as well as numerical simulations, allowing us to contrast different data sources. We use hindcast simulations performed with Polar-WRF over the Antarctic Peninsula on a nested domain configuration at 45 km (PWRF-45) and 15 km (PWRF-15) spatial resolutions for the period 1991-2015. In addition, we include hindcast simulations of KNMI-RACMO21P obtained from the CORDEX-Antarctica domain (~50 km) for further comparisons. Results show that there is a marked windward warming trend except during summer. This windward warming trend is particularly notable in the autumn season and likely to be associated with the recent deepening of the Amundsen/Bellingshausen Sea low and warm advection towards the Antarctic Peninsula. On the other hand, an overall summer cooling is characterized by the strengthening of the Weddell Sea low as well as an anticyclonic trend over the Amundsen Sea accompanied by northward winds. The persistent cooling trend observed at the Larsen Ice Shelf station is not captured by ERA-Interim, whereas hindcast simulations indicate that there is a clear pattern of windward warming and leeward cooling. Furthermore, larger temporal correlations and lower differences exhibited by PWRF-15 illustrate the existence of the added value in the higher spatial resolution simulation. |
| Climate impacts of the El Niño–Southern Oscillation on South America | Nature Reviews Earth & Environment | Cai, W.; McPhaden, M.; Grimm, A.; Rodrigues, R.; Taschetto, A.; Garreaud, R.; Dewitte, B.; Poveda, G.; Ham, Y.; Santoso, A.; Ng, B.; Anderson, W.; Wang, G.; Geng, T.; Jo, H.; Marengo, J.; Alves, L.; Osman, M.; Li, S.; Wu, L.; Karamperidou, C.; Takahashi, K.; Vera, C. | 2020 | Agua y Extremos | 10.1038/s43017-020-0040-3 | http://www.nature.com/articles/s43017-020-0040-3 | 215-231 | Vol: 1 Issue: 4 | 2662-138X | Thomson Reuters ISI (SCIE) | | English | The climate of South America (SA) has long held an intimate connection with El Niño, historically describing anomalously warm sea-surface temperatures off the coastline of Peru. Indeed, throughout SA, precipitation and temperature exhibit a substantial, yet regionally diverse, relationship with the El Niño–Southern Oscillation (ENSO). For example, El Niño is typically accompanied by drought in the Amazon and north-eastern SA, but flooding in the tropical west coast and south-eastern SA, with marked socio-economic effects. In this Review, we synthesize the understanding of ENSO teleconnections to SA. Recent efforts have sought improved understanding of ocean–atmosphere processes that govern the impact, inter-event and decadal variability, and responses to anthropogenic warming. ENSO’s impacts have been found to vary markedly, affected not only by ENSO diversity, but also by modes of variability within and outside of the Pacific. However, while the understanding of ENSO–SA relationships has improved, with implications for prediction and projection, uncertainty remains in regards to the robustness of the impacts, inter-basin climate interactions and interplay with greenhouse warming. A coordinated international effort is, therefore, needed to close the observational, theoretical and modelling gaps currently limiting progress, with specific efforts in extending palaeoclimate proxies further back in time, reducing systematic model errors and improving simulations of ENSO diversity and teleconnections. © 2020, Springer Nature Limited. |
| Transformation of social capital during and after a disaster event: the cases Chañaral and Diego de Almagro, Atacama Region, Chile | Natural Hazards | Castro-Correa, C.; Aldunce Ide, P.; Wyndham Vásquez, K.; Mena Maldonado, D.; Pérez Tello, S. | 2020 | Agua y Extremos | 10.1007/s11069-020-04091-9 | http://link.springer.com/10.1007/s11069-020-04091-9 | 2427-2440 | Vol: 103 Issue: 2 | 0921-030X, 1573-0840 | Thomson Reuters ISI (SCIE) | | English | This article analyzes the impact of socio-natural disasters on social capital at a local level, studying the cases of the communities of Chañaral and Diego de Almagro after the flooding and mudflow disasters of 2015. Specifically, we explore different dynamics of social capital in the response to the emergency, recovery and reconstruction stages, exploring its role in strengthening adaptation and resilience capacities for disaster risk reduction. Through the qualitative analysis of semi-structured interviews with survivors of the disaster, we explore the nature and role of social trust and its influence on the formation and consolidation of bonding, bridging and linking social capital in the context of disaster is analyzed. The results unpack the role of social capital in the response, recovery and reconstruction processes after a disaster event, which directly influences the development and consolidation of capacities for community adaptation, highlighting the role of trust for the strengthening of resilience. Likewise, the article provides details about the role of institutions and authorities in the consolidation of bridging and linking social capital, which requires the generation of formal and fluid communication channels that allow for the creation of trust, not only among the members of the community, but between the community and the institutions and authorities. |
| First snow, glacier and groundwater contribution quantification in the upper Mendoza River basin using stable water isotopes | Isotopes in Environmental and Health Studies | Crespo, S.; Fernandoy, F.; Cara, L.; Klarian, S.; Lavergne, C. | 2020 | Agua y Extremos | 10.1080/10256016.2020.1797713 | https://www.tandfonline.com/doi/full/10.1080/10256016.2020.1797713 | 566-585 | Vol: 56 Issue: 5-6 | 1025-6016, 1477-2639 | Thomson Reuters ISI (SCIE) | | English | The Mendoza River streamflow, South America (∼32 °S), derives almost exclusively from winter snow precipitation falling in the Andes. Almost 70% of the water feeding the river originates in the Cordillera Principal geological province. In addition to the snow that precipitates in this area, there are 951 cryoforms providing meltwater to the upper catchment. Given the high inter-annual variability of snowfall and the megadrought affecting the region since 2010, it is crucial to quantify the contribution from different water sources buffering the Mendoza River runoff. Combining instrumental records of streamflow from glaciers and rivers, meteorological data, remote sensing of snow-covered areas and ionic and stable isotope analysis of different water sources, this study attempts to understand the hydrological contribution of different water sources to the basin. We demonstrated for the first time the relevance of different water sources in addition to snow in a dry period. During the melting season, 65% of the streamwaters originated from the glaciers (i.e. 50 and 15% from glaciers and rock glaciers, respectively), representing a higher proportion compared to snowmelt (17%). Groundwater input showed relatively large contributions, averaging 18%. This work offers information to develop adaptation strategies for future climate change scenarios in the region. |
| Where Does the Chilean Aconcagua River Come from? Use of Natural Tracers for Water Genesis Characterization in Glacial and Periglacial Environments | Water | Crespo, S.; Lavergne, C.; Fernandoy, F.; Muñoz, A.; Cara, L.; Olfos-Vargas, S. | 2020 | Agua y Extremos | 10.3390/w12092630 | https://www.mdpi.com/2073-4441/12/9/2630 | 2630 | Vol: 12 Issue: 9 | 2073-4441 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The Aconcagua river basin (Chile, 32 °S) has suffered the effects of the megadrought over the last decade. The severe snowfall deficiency drastically modified the water supply to the catchment headwaters. Despite the recognized snowmelt contribution to the basin, an unknown streamflow buffering effect is produced by glacial, periglacial and groundwater inputs, especially in dry periods. Hence, each type of water source was characterized and quantified for each season, through the combination of stable isotope and ionic analyses as natural water tracers. The δ18O and electric conductivity were identified as the key parameters for the differentiation of each water source. The use of these parameters in the stable isotope mixing “simmr” model revealed that snowmelt input accounted 52% in spring and only 22–36% during the rest of the year in the headwaters. While glacial supply contributed up to 34%, both groundwater and periglacial exhibited a remarkable contribution around 20% with some seasonal variations. Downstream, glacial contribution averaged 15–20%, groundwater seasonally increased up to 46%, and periglacial input was surprisingly high (i.e., 14–21%). The different water sources contribution quantification over time for the Aconcagua River reported in this work provides key information for water security in this territory. |
| Connection between Antarctic Ozone and Climate: Interannual Precipitation Changes in the Southern Hemisphere | Atmosphere | Damiani, A.; Cordero, R.; Llanillo, P.; Feron, S.; Boisier, J.; Garreaud, R.; Rondanelli, R.; Irie, H.; Watanabe, S. | 2020 | Agua y Extremos; Zonas Costeras | 10.3390/atmos11060579 | https://www.mdpi.com/2073-4433/11/6/579 | 579 | Vol: 11 Issue: 6 | 2073-4433 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access; Green Open Access | English | In this study, we explored the connection between anomalies in springtime Antarctic ozone and all-year precipitation in the Southern Hemisphere by using observations from 1960–2018 and coupled simulations for 1960–2050. The observations showed that this correlation was enhanced during the last several decades, when a simultaneously increased coupling between ozone and Southern Annular Mode (SAM) anomalies became broader, covering most of the following summer and part of the previous winter. For eastern Australia, the ozone–precipitation connection shows a greater persistence toward the following summer than for other regions. On the other hand, for South America, the ozone–precipitation correlation seems more robust, especially in the early summer. There, the correlation also covers part of the previous winter, suggesting that winter planetary waves could affect both parameters. Further, we estimated the sensitivity of precipitation to changes in Antarctic ozone. In both observations and simulations, we found comparable sensitivity values during the spring–summer period. Overall, our results indicate that ozone anomalies can be understood as a tracer of stratospheric circulation. However, simulations indicate that stratospheric ozone chemistry still contributes to strengthening the interannual relationship between ozone and surface climate. Because simulations reproduced most of the observed connections, we suggest that including ozone variability in seasonal forecasting systems can potentially improve predictions. |
| Hydroclimate of the Andes Part I: Main Climatic Features | Frontiers in Earth Science | Espinoza, J.; Garreaud, R.; Poveda, G.; Arias, P.; Molina-Carpio, J.; Masiokas, M.; Viale, M.; Scaff, L. | 2020 | Agua y Extremos | 10.3389/feart.2020.00064 | https://www.frontiersin.org/article/10.3389/feart.2020.00064/full | 64 | Vol: 8 | 2296-6463 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The Andes is the longest cordillera in the world and extends from northern South America to the southern extreme of the continent (from 11°N to 53°S). The Andes runs through seven countries and is characterized by a wide variety of ecosystems strongly related to the contrasting climate over its eastern and western sides, as well as along its latitudinal extension. This region faces very high potential impacts of climate change, which could affect food and water security for about 90 million people. In addition, climate change represents an important threat on biodiversity, particularly in the tropical Andes, which is the most biodiverse region on Earth. From a scientific and societal view, the Andes exhibits specific challenges because of its unique landscape and the fragile equilibrium between the growing population and its environment. In this manuscript, we provide an updated review of the most relevant scientific literature regarding the hydroclimate of the Andes with an integrated view of the entire Andes range. This review paper is presented in two parts. Part I is dedicated to summarize the scientific knowledge about the main climatic features of the Andes, with emphasis on mean large-scale atmospheric circulation, the Andes-Amazon hydroclimate interconnections and the most distinctive diurnal and annual cycles of precipitation. Part II, which is also included in the research topic “Connecting Mountain Hydroclimate Through the American Cordilleras,” focuses on the hydroclimate variability of the Andes at the sub-continental scale, including the effects of El Niño-Southern Oscillation. © Copyright © 2020 Espinoza, Garreaud, Poveda, Arias, Molina-Carpio, Masiokas, Viale and Scaff. |
| Transforming knowledge systems for life on Earth: Visions of future systems and how to get there | Energy Research & Social Science | Fazey, I.; Schäpke, N.; Caniglia, G.; Hodgson, A.; Kendrick, I.; Lyon, C.; Page, G.; Patterson, J.; Riedy, C.; Strasser, T.; Verveen, S.; Adams, D.; Goldstein, B.; Klaes, M.; Leicester, G.; Linyard, A.; McCurdy, A.; Ryan, P.; Sharpe, B.; Silvestri, G.; Abdurrahim, A.; Abson, D.; Adetunji, O.; Aldunc... | 2020 | Agua y Extremos | 10.1016/j.erss.2020.101724 | https://linkinghub.elsevier.com/retrieve/pii/S2214629620302991 | 101724 | Vol: 70 | 22146296 | Thomson Reuters ISI (SSCI) | All Open Access; Hybrid Gold Open Access | English | Formalised knowledge systems, including universities and research institutes, are important for contemporary societies. They are, however, also arguably failing humanity when their impact is measured against the level of progress being made in stimulating the societal changes needed to address challenges like climate change. In this research we used a novel futures-oriented and participatory approach that asked what future envisioned knowledge systems might need to look like and how we might get there. Findings suggest that envisioned future systems will need to be much more collaborative, open, diverse, egalitarian, and able to work with values and systemic issues. They will also need to go beyond producing knowledge about our world to generating wisdom about how to act within it. To get to envisioned systems we will need to rapidly scale methodological innovations, connect innovators, and creatively accelerate learning about working with intractable challenges. We will also need to create new funding schemes, a global knowledge commons, and challenge deeply held assumptions. To genuinely be a creative force in supporting longevity of human and non-human life on our planet, the shift in knowledge systems will probably need to be at the scale of the enlightenment and speed of the scientific and technological revolution accompanying the second World War. This will require bold and strategic action from governments, scientists, civic society and sustained transformational intent. |
| The Central Chile Mega Drought (2010–2018): A climate dynamics perspective | International Journal of Climatology | Garreaud, R.; Boisier, J.; Rondanelli, R.; Montecinos, A.; Sepúlveda, H.; Veloso‐Aguila, D. | 2020 | Agua y Extremos; Zonas Costeras | 10.1002/joc.6219 | https://onlinelibrary.wiley.com/doi/abs/10.1002/joc.6219 | 421-439 | Vol: 40 Issue: 1 | 0899-8418 | Thomson Reuters ISI (SCIE) | | English | Central Chile, home to more than 10 million inhabitants, has experienced an uninterrupted sequence of dry years since 2010 with mean rainfall deficits of 20–40%. The so‐called Mega Drought (MD) is the longest event on record and with few analogues in the last millennia. It encompasses a broad area, with detrimental effects on water availability, vegetation and forest fires that have scaled into social and economical impacts. Observations and reanalysis data reveal that the exceptional length of the MD results from the prevalence of a circulation dipole‐hindering the passage of extratropical storms over central Chile—characterized by deep tropospheric anticyclonic anomalies over the subtropical Pacific and cyclonic anomalies over the Amundsen–Bellingshausen Sea. El Niño Southern Oscillation (ENSO) is a major modulator of such dipole, but the MD has occurred mostly under ENSO‐neutral conditions, except for the winters of 2010 (La Niña) and 2015 (strong El Niño). Climate model simulations driven both with historical forcing (natural and anthropogenic) and observed global SST replicate the south Pacific dipole and capture part of the rainfall anomalies. Idealized numerical experiments suggest that most of the atmospheric anomalies emanate from the subtropical southwest Pacific, a region that has experienced a marked surface warming over the last decade. Such warming may excite atmospheric Rossby waves whose propagation intensifies the circulation pattern leading to dry conditions in central Chile. On the other hand, anthropogenic forcing (greenhouse gases concentration increase and stratospheric ozone depletion) and the associated positive trend of the Southern Annular Mode also contribute to the strength of the south Pacific dipole and hence to the intensity and longevity of the MD. Given the concomitance of the seemingly natural (ocean sourced) and anthropogenic forcing, we anticipate only a partial recovery of central Chile precipitation in the decades to come. |
| Fire history in Andean Araucaria–Nothofagus forests: coupled influences of past human land-use and climate on fire regimes in north-west Patagonia | International Journal of Wildland Fire | González, M.; Muñoz, A.; González-Reyes, A.; Christie, D.; Sibold, J. | 2020 | Agua y Extremos; Cambio de Uso de Suelo | 10.1071/WF19174 | http://www.publish.csiro.au/?paper=WF19174 | 649 | Vol: 29 Issue: 8 | 1049-8001 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | Historical fire regimes are critical for understanding the potential effects of changing climate and human land-use on forest landscapes. Fire is a major disturbance process affecting the Andean Araucaria forest landscape in north-west Patagonia. The main goals of this study were to reconstruct the fire history of the Andean Araucaria–Nothofagus forests and to evaluate the coupled influences of climate and humans on fire regimes. Reconstructions of past fires indicated that the Araucaria forest landscape has been shaped by widespread, stand-replacing fires favoured by regional interannual climate variability related to major tropical and extratropical climate drivers in the southern hemisphere. Summer precipitation and streamflow reconstructions tended to be below average during fire years. Fire events were significantly related to positive phases of the Southern Annular Mode and to warm and dry summers following El Niño events. Although Euro-Chilean settlement (1883–1960) resulted in widespread burning, cattle ranching by Pehuenche Native Americans during the 18th and 19th centuries also appears to have changed the fire regime. In the context of climate change, two recent widespread wildfires (2002 and 2015) affecting Araucaria forests appear to be novel and an early indication of a climate change driven shift in fire regimes in north-west Patagonia. |
| Informe a las naciones: Incendios en Chile: causas, impactos y resiliencia. | | González, M.; Sapiains A., R.; Gómez-González, S.; Garreaud, R.; Miranda, A.; Galleguillos, M.; Jacques-Coper, M.; Pauchard, A.; Hoyos-Santillan, J.; Cordero, L.; Vasquez-Lavin, F.; Lara, A.; Aldunce, P.; Delgado, V.; Arriagada, R.; Ugarte, A.; Sepulveda-Jauregui, A.; Farías, L.; Garcia, R.; Rondane... | 2020 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2020/01/Informe-CR2-IncendiosforestalesenChile.pdf | 84 | | | | | Spanish | Los resultados presentados en este informe son parte del trabajo interdisciplinario que realiza el Centro de Ciencia
del Clima y la Resiliencia (CR)2.
El (CR)2 es un centro de excelencia financiado por el programa FONDAP de CONICYT (Proyecto 15110009) en el cual
participan cerca de 60 científicos asociados a la Universidad de Chile, la Universidad de Concepción y la Universidad
Austral de Chile.
La versión electrónica de este documento está disponible en el sitio web www.cr2.cl/incendios |
| Thermo- and physicochemical properties of native and exotic forest species of Valparaíso, Chile, as essential information for fire risk management | International Journal of Wildland Fire | Guerrero, F.; Toledo, M.; Ripoll, N.; Espinoza, L.; Morales, R.; Muñoz, A.; Taborga, L.; Carrasco, Y. | 2020 | Agua y Extremos | 10.1071/WF19086 | http://www.publish.csiro.au/?paper=WF19086 | 675 | Vol: 29 Issue: 8 | 1049-8001 | Thomson Reuters ISI (SCIE) | | English | Wildfires in the Valparaı́so region (Chile) account for one of the main threats to local biodiversity, ecosystem
services and infrastructure. This study focused on producing an initial record of thermo- and physicochemical properties of local forest species. For this purpose, leaf samples of species found in the Peñuelas Lake National Reserve, namely Pinus
radiata, Eucalyptus globulus, Acacia dealbata, Quillaja saponaria and Cryptocarya alba, were collected and analysed.
Higher and lower heating value, flash point, density and moisture content tests were performed for each sample. Overall
results showed that lower heating values measured for both native and exotic species could indicate a high energy release source in wildfires. However, differences in the flash point between species indicated that C. alba and E. globulus had a lower ignition resistance than other species tested, possibly due to a lower flash point. In contrast, Q. saponaria and A. dealbata had the highest flash point for native and exotic species respectively. Finally, all presented data and procedures were aimed at establishing a foundation for a national database of critical forest species properties to be used in wildfire simulation tools. This database will enhance forest fire management effectiveness in Chile. |
| Two Centuries of Hydroclimatic Variability Reconstructed From Tree‐Ring Records Over the Amazonian Andes of Peru | Journal of Geophysical Research: Atmospheres | Humanes‐Fuente, V.; Ferrero, M.; Muñoz, A.; González‐Reyes, Á.; Requena‐Rojas, E.; Barichivich, J.; Inga, J.; Layme‐Huaman, E. | 2020 | Agua y Extremos | 10.1029/2020JD032565 | https://onlinelibrary.wiley.com/doi/10.1029/2020JD032565 | art: e2020JD032565 | Vol: 125 Issue: 18 | 2169-897X | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | Almost half of the tributaries of the Amazon River originate in the tropical Andes and support large populations in mountain regions and downstream areas. However, it is difficult to assess hydroclimatic conditions or to evaluate future scenarios due to the scarcity of long, high‐quality instrumental records. Data from the Global Precipitation Climatology Project (GPCP) provide a complete record since 1979 and offer a good representation of rainfall over the tropical Andes. Longer records are needed to improve our understanding of rainfall variability and summer monsoon behavior at various scales. We developed the first annually resolved precipitation reconstruction for the tropical Andes in Peru, based on tree‐ring chronologies of Cedrela and Juglans species. The annual (November–October) reconstruction extends the short instrumental records back to 1817, explaining 68% of the total variance of precipitation over the 1979–2007 calibration period. The reconstruction reveals the well‐documented influence of El Niño‐Southern Oscillation (ENSO) on Amazon Rainfall at interannual scales (~19% of total variance) and significant multidecadal variability with alternating periods of about 40 years (~13% of rainfall variability) related to the Atlantic Multidecadal Oscillation (AMO). Both oscillatory modes can explain dry and humid periods observed within the reconstruction and are likely associated with the negative trends of rainfall in the short instrumental records and the increased drought recurrence in recent decades. Our results show that montane tropical tree rings can be used to reconstruct precipitation with exceptionally high fidelity, characterize the interannual to multidecadal variability, and identify remote forcings in the hydroclimate over the Andean Amazon Basin of Peru. |
| Informe a las naciones: El aire que respiramos: pasado, presente y futuro – Contaminación atmosférica por MP2,5 en el centro y sur de Chile | | Huneeus, N.; Urquiza, A.; Gayo, E.; Osses, M.; Arriagada, R.; Valdés, M.; Álamos, N.; Amigo, C.; Arrieta, D.; Basoa, K.; Billi, M.; Blanco, G.; Boisier, J.; Calvo, R.; Casielles, I.; Castro, M.; Chahúan, J.; Christie, D.; Cordero, L.; Correa, V.; Cortés, J.; Fleming, Z.; Gajardo, N.; Gallardo, L.; G... | 2020 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2020/09/Informe_Contaminacion_Espanol_2020.pdf | 102 | | | cr2.cl | | Spanish | Los resultados presentados en este informe son parte del trabajo interdisciplinario que realiza el Centro de Ciencia
del Clima y la Resiliencia (CR)2.
El (CR)2 es un centro de excelencia financiado por el programa FONDAP de CONICYT (Proyecto 15110009) en el cual
participan cerca de 60 científicos asociados a la Universidad de Chile, la Universidad de Concepción y la Universidad
Austral de Chile.
La versión electrónica de este documento está disponible en el sitio web www.cr2.cl/incendios |
| Daily and seasonal variation of the surface temperature lapse rate and 0°C isotherm height in the western subtropical Andes | International Journal of Climatology | Ibañez, M.; Gironás, J.; Oberli, C.; Chadwick, C.; Garreaud, R. | 2020 | Agua y Extremos | 10.1002/joc.6743 | https://onlinelibrary.wiley.com/doi/abs/10.1002/joc.6743 | joc.6743 | Vol: 41 Issue: S1 | 0899-8418, 1097-0088 | Thomson Reuters ISI (SCIE) | | English | The spatial distribution of surface air temperatures is essential for understanding and modelling high-relief environments. Good estimations of the surface temperature lapse rate (STLR) and the 0°C isotherm height (H0) are fundamental for hydrological modelling in mountainous basins. Although STLR changes in space and time, it is typically assumed to be constant leading to errors in the estimation of direct-runoff volumes and flash-floods risk assessment. This paper characterizes daily and seasonal temporal variations of the in-situ STLR and H0 over the western slope of the subtropical Andes (central Chile). We use temperature data collected during 2 years every 10 min by a 16 sensors network in a small catchment with elevations ranging between 700 and 3,250 m. The catchment drains directly into Santiago, the Chilean capital with more than seven million inhabitants. Resulting values are compared against those obtained using off-site, operational data sets. Significant intra- and inter-day variations of the in-situ STLR were found, likely reflecting changes in the low-level temperature inversion during dry conditions. The annual average in-situ STLR is −5.9°C/km during wet-weather conditions. Furthermore, STLR and H0 estimations using off-site gauges are extremely sensitive to the existence of gauging stations at high elevations. |
| +A 5680-year tree-ring temperature record for southern South America | Quaternary Science Reviews | Lara, A.; Villalba, R.; Urrutia-Jalabert, R.; González-Reyes, A.; Aravena, J.; Luckman, B.; Cuq, E.; Rodríguez, C.; Wolodarsky-Franke, A. | 2020 | Agua y Extremos; Cambio de Uso de Suelo | 10.1016/j.quascirev.2019.106087 | https://linkinghub.elsevier.com/retrieve/pii/S0277379119306924 | 106087 | Vol: 228 | 0277-3791 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | It is widely documented that the Earth’s surface temperatures have increased in recent decades. However, temperature increment patterns are not uniform around the globe, showing different or even contrasting trends. Here we present a mean maximum summer temperature record, based on tree-ring widths, over the past 5682 years (3672BC – 2009AD) for southern South America (SSA), covering from mid-Holocene to the present. This is the longest such record for the Southern Hemisphere (SH), and expands available annual proxy climate records for this region in more than 2060 years. Our record explains 49% of the temperature variation, and documents two major warm periods between 3140–2800BC and 70BC – 150AD, which coincide with the lack of evidence of glacier advances in SSA. Recent decades in the reconstruction (1959–2009) show a warming trend that is not exceptional in the context of the last five millennia. The long-term relationship between our temperature reconstruction and a reconstructed total solar irradiance record, with coinciding cycles at 293, 372, 432–434, 512 and 746 years, indicate a persistent influence of solar forcing on centennial climate variability in SSA. At interannual to interdecadal scales, reconstructed temperature is mainly related to the internal climate variability of the Pacific Ocean, including El Niño Southern Oscillation (ENSO) and longer oscillations. Our study reveals the need to characterize regional-scale climate variability and its drivers, which in the context of global-scale processes such as anthropogenic warming, interact to modulate local climate affecting humans and ecosystems. |
| Future Changes in the Free Tropospheric Freezing Level and Rain–Snow Limit: The Case of Central Chile | Atmosphere | Mardones, P.; Garreaud, R. | 2020 | Agua y Extremos | 10.3390/atmos11111259 | https://www.mdpi.com/2073-4433/11/11/1259 | 1259 | Vol: 11 Issue: 11 | 2073-4433 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The freezing level in the free troposphere often intercepts the terrain of the world’s major mountain ranges, creating a rain–snow limit. In this work, we use the free tropospheric height of the 0 °C isotherm (H0) as a proxy of both levels and study its distribution along the western slope of the subtropical Andes (30°–38° S) in present climate and during the rest of the 21st century. This portion of the Andes corresponds to central Chile, a highly populated region where warm winter storms have produced devastating landslides and widespread flooding in the recent past. Our analysis is based on the frequency distribution of H0 derived from radiosonde and surface observations, atmospheric reanalysis and climate simulations. The future projections primarily employ a scenario of heavy greenhouse gasses emissions (RCP8.5), but we also examine the more benign RCP4.5 scenario. The current H0 distribution along the central Chile coast shows a gradual decrease southward, with mean heights close to 2600 m ASL (above sea level) at 30 °C S to 2000 m ASL at 38° S for days with precipitation, about 800 m lower than during dry days. The mean value under wet conditions toward the end of the century (under RCP8.5) is close to, or higher than, the upper quartile of the H0 distribution in the current climate. More worrisome, H0 values that currently occur only 5% of the time will be exceeded in about a quarter of the rainy days by the end of the century. Under RCP8.5, even moderate daily precipitation can increase river flow to levels that are considered hazardous for central Chile. |
| Six hundred years of South American tree rings reveal an increase in severe hydroclimatic events since mid-20th century | Proceedings of the National Academy of Sciences | Morales, M.; Cook, E.; Barichivich, J.; Christie, D.; Villalba, R.; LeQuesne, C.; Srur, A.; Ferrero, M.; González-Reyes, Á.; Couvreux, F.; Matskovsky, V.; Aravena, J.; Lara, A.; Mundo, I.; Rojas, F.; Prieto, M.; Smerdon, J.; Bianchi, L.; Masiokas, M.; Urrutia-Jalabert, R.; Rodriguez-Catón, M.; Muñoz... | 2020 | Agua y Extremos; Cambio de Uso de Suelo | 10.1073/pnas.2002411117 | http://www.pnas.org/lookup/doi/10.1073/pnas.2002411117 | 16816-16823 | Vol: 117 Issue: 29 | 0027-8424, 1091-6490 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | South American (SA) societies are highly vulnerable to droughts and pluvials, but lack of long-term climate observations severely limits our understanding of the global processes driving climatic variability in the region. The number and quality of SA climate-sensitive tree ring chronologies have significantly increased in recent decades, now providing a robust network of 286 records for characterizing hydroclimate variability since 1400 CE. We combine this network with a self-calibrated Palmer Drought Severity Index (scPDSI) dataset to derive the South American Drought Atlas (SADA) over the continent south of 12°S. The gridded annual reconstruction of austral summer scPDSI is the most spatially complete estimate of SA hydroclimate to date, and well matches past historical dry/wet events. Relating the SADA to the Australia–New Zealand Drought Atlas, sea surface temperatures and atmospheric pressure fields, we determine that the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) are strongly associated with spatially extended droughts and pluvials over the SADA domain during the past several centuries. SADA also exhibits more extended severe droughts and extreme pluvials since the mid-20th century. Extensive droughts are consistent with the observed 20th-century trend toward positive SAM anomalies concomitant with the weakening of midlatitude Westerlies, while low-level moisture transport intensified by global warming has favored extreme rainfall across the subtropics. The SADA thus provides a long-term context for observed hydroclimatic changes and for 21st-century Intergovernmental Panel on Climate Change (IPCC) projections that suggest SA will experience more frequent/severe droughts and rainfall events as a consequence of increasing greenhouse gas emissions. |
| Timing and structure of vegetation, fire, and climate changes on the Pacific slope of northwestern Patagonia since the last glacial termination | Quaternary Science Reviews | Moreno, P. | 2020 | Agua y Extremos | 10.1016/j.quascirev.2020.106328 | https://linkinghub.elsevier.com/retrieve/pii/S0277379120302900 | 106328 | Vol: 238 | 0277-3791 | Thomson Reuters ISI (SCIE) | | English | By virtue of its location in the southern mid-latitudes, northwestern Patagonia (40°-44°S) offers the opportunity to unravel the mechanisms involved in the initiation and propagation of paleoclimate signals of hemispheric and global significance. Of particular importance is deciphering the evolution of the Southern Westerly Winds (SWW) considering their influence at continental, zonal, hemispheric, and global scale. Here I present a multi-decadal record from Lago Proschle, a small closed-basin lake located on the Pacific slope of northwestern Patagonia, to examine the timing and structure of vegetation, fire, and climate change along a continuum since the onset of the Last Glacial Termination (T1). The record shows rapid glacier recession during T1, reaching the western Andean foothills in ∼400 years or less. Nothofagus-dominated forests established between ∼17.4–17 ka, followed by closed-canopy North Patagonian Rain Forests (NPRF) with shade-tolerant thermophilous trees between ∼16.3–15.4 ka. These changes suggest an abrupt warming trend and an increase in precipitation at ∼16.3 ka, associated with a northward shift of the SWW. Subsequent increases in cold-tolerant hygrophilous trees between ∼15.4–12.8 ka imply a shift to cold, more humid conditions during the Antarctic Cold Reversal, suggesting stronger SWW influence. This was followed by stand-replacing fires brought by a sudden decline in summer precipitation at ∼12.8 ka, associated with a millennial-scale southward shift of the SWW which was contemporaneous with the onset of the Younger Dryas. Dominance of thermophilous, summer-drought tolerant Valdivian rainforest trees and high fire activity ensued between ∼10.3–7.8 ka, suggesting peak warmth and overall decline in annual precipitation associated with weakening of the SWW during the early Holocene. A multi-millennial cooling and wetting trend started at ∼7.8 ka, brought by stronger SWW influence, followed by recurrent, centennial-scale variations in temperature and precipitation starting at ∼6.4 ka. Deforestation, fire, and spread of non-native herbs by Chilean/European settlers began during the late 18th century. Abrupt vegetation changes in the Lago Proschle record were driven by rapid climate changes over the last 17,400 years amplified, in some instances, by fire disturbance. © 2020 Elsevier Ltd |
| Water Crisis in Petorca Basin, Chile: The Combined Effects of a Mega-Drought and Water Management | Water | Muñoz A.; Klock-Barría, K.; Alvarez-Garreton, C.; Aguilera-Betti, I.; González-Reyes, Á.; Lastra, J.; Chávez, R.; Barría, P.; Christie, D.; Rojas-Badilla, M.; Quesne, C. | 2020 | Agua y Extremos | 10.3390/w12030648 | https://www.mdpi.com/2073-4441/12/3/648 | 648 | Vol: 12 Issue: 3 | 2073-4441 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Since 2010, Chile has experienced one of the most severe droughts over the last century, the so-called mega-drought (MD). The MD conditions, combined with intensive agricultural activities and the current water management system, have led to water scarcity problems in Mediterranean and Semi-arid regions of Chile. An emblematic case is the Petorca basin, where a water crisis is undergone. To characterize this crisis, we analyzed water provision by using tree-ring records, remote sensing, instrumental data, and allocated water rights within the basin. Results indicate that the MD is the most severe dry period over the last 700-years of streamflow reconstruction. During the MD, streamflow and water bodies of the upper parts of the basin have been less affected than mid and low areas of this valley, where consumptive withdrawals reach up to 18% of the mean annual precipitation. This extracted volume is similar to the MD mean annual precipitation deficits. The impacts of the current drought, along with the drier climate projections for Central Chile, emphasize the urgency for faster policy changes related to water provision. Climate change adaptation plans and policies should enhance the current monitoring network and the public control of water use to secure the water access for inhabitants and productive activities. |
| Raco Wind at the Exit of the Maipo Canyon in Central Chile: Climatology, Special Observations, and Possible Mechanisms | Journal of Applied Meteorology and Climatology | Muñoz R.; Armi, L.; Rutllant, J.; Falvey, M.; Whiteman, C.; Garreaud, R.; Arriagada, A.; Flores, F.; Donoso, N. | 2020 | Agua y Extremos | 10.1175/JAMC-D-19-0188.1 | http://journals.ametsoc.org/doi/10.1175/JAMC-D-19-0188.1 | 725-749 | Vol: 59 Issue: 4 | 1558-8424, 1558-8432 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Raco is the local name given to a strong (gusts up to 17 m s
−1
), warm, and dry down-valley wind observed at the exit of the Maipo River Canyon in central Chile. Its climatology is documented based on eight years of surface measurements near the canyon exit together with a more complete characterization of its structure during an intensive observational period (IOP) carried out in July 2018. Raco winds occur in the cold season under well-defined synoptic conditions, beginning abruptly at any time during the night, reaching maximum hourly averages around 10 m s
−1
, and terminating around noon with the onset of afternoon westerly up-valley winds. About 25% of the days in May–August have more than six raco hours between 0100 and 1200 LT, and raco episodes last typically 1–2 days. The sudden appearance of raco winds at the surface can be accompanied by conspicuous warming (up to 10°C) and drying (up to 3 g kg
−1
). Raco winds are associated with a strong along-canyon pressure gradient, a regional pressure fall, and clear skies. During the IOP, radiosondes launched from both extremes of the canyon exit corridor showed a nocturnal easterly jet at 700 m AGL that occasionally descended rapidly to the surface, producing the raco. Transects along the canyon performed with a mobile ceilometer revealed a sharp frontlike feature between the cold pool over the Santiago Valley and the raco-affected conditions in the Maipo Canyon. Possible factors producing the easterly jet aloft and its occasional descent toward the surface are discussed, and a gap-wind mechanism is postulated to be at work. |
| The deglaciation of the Americas during the Last Glacial Termination | Earth-Science Reviews | Palacios, D.; Stokes, C.; Phillips, F.; Clague, J.; Alcalá-Reygosa, J.; Andrés, N.; Angel, I.; Blard, P.; Briner, J.; Hall, B.; Dahms, D.; Hein, A.; Jomelli, V.; Mark, B.; Martini, M.; Moreno, P.; Riedel, J.; Sagredo, E.; Stansell, N.; Vázquez-Selem, L.; Vuille, M.; Ward, D. | 2020 | Agua y Extremos | 10.1016/j.earscirev.2020.103113 | https://linkinghub.elsevier.com/retrieve/pii/S001282521930652X | 103113 | Vol: 203 | 0012-8252 | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | This paper reviews current understanding of deglaciation in North, Central and South America from the Last Glacial Maximum to the beginning of the Holocene. Together with paleoclimatic and paleoceanographic data, we compare and contrast the pace of deglaciation and the response of glaciers to major climate events. During the Global Last Glacial Maximum (GLGM, 26.5-19 ka), average temperatures decreased 4° to 8°C in the Americas, but precipitation varied strongly throughout this large region. Many glaciers in North and Central America achieved their maximum extent during the GLGM, whereas others advanced even farther during the subsequent Heinrich Stadial 1 (HS-1). Glaciers in the Andes also expanded during the GLGM, but that advance was not the largest, except on Tierra del Fuego. HS-1 (17.5-14.6 ka) was a time of general glacier thickening and advance throughout most of North and Central America, and in the tropical Andes; however, glaciers in the temperate and subpolar Andes thinned and retreated during this period. During the Bølling-Allerød interstadial (B-A, 14.6-12.9 ka), glaciers retreated throughout North and Central America and, in some cases, completely disappeared. Many glaciers advanced during the Antarctic Cold Reversal (ACR, 14.6-12.9 ka) in the tropical Andes and Patagonia. There were small advances of glaciers in North America, Central America and in northern South America (Venezuela) during the Younger Dryas (12.9-11.7 ka), but glaciers in central and southern South America retreated during this period, except on the Altiplano where advances were driven by an increase in precipitation. Taken together, we suggest that there was a climate compensation effect, or ‘seesaw’, between the hemispheres, which affected not only marine currents and atmospheric circulation, but also the behavior of glaciers. This seesaw is consistent with the opposing behavior of many glaciers in the Northern and Southern Hemispheres. |
| Informe Proyecto ARClim: Atlas de Riegos Climáticos para Chile | | Pica-Téllez, A.; Garreaud, R.; Meza, F.; Bustos, S.; Falvey, M.; Ibarra, M.; Silva, M.; Duarte, K.; Ormazábal, R.; Dittborn, R. | 2020 | Agua y Extremos | | https://www.cr2.cl/informe-proyecto-arclim-atlas-de-riesgos-climaticos-para-chile/ | 193 | | | | | Spanish | Este documento, tiene por finalidad describir el proceso de desarrollo de la Plataforma ARClim, principal producto del proyecto “Atlas de Riesgo climático para Chile”, proyecto Apoyado por el Programa Mundial de Evaluación y Gestión de Riesgos para la Adaptación al Cambio Climático (Pérdidas y Daños)” por encargo del Ministerio Federal de Cooperación Económica y Desarrollo (BMZ) a través de la Agencia para la Cooperación Técnica GIZ (Deutsche Gesellschaft für Internationale Zusammenarbeit), con el objetivo de colaborar con el Ministerio de Medio Ambiente del Gobierno de Chile, aportando al fortalecimiento de las capacidades nacionales en el marco de los desafíos del Cambio Climático; generando Mapas de Riesgos de distintos sectores frente al Cambio Climático en el país. Para llevar a cabo este desafío, participaron 96 investigadores y 24 instituciones especializadas en distintas áreas del cambio climático, las que fueron liderados por el Centro de Ciencia del Clima y la Resiliencia (CR2 ) y el Centro de Cambio Global UC. |
| High Impact Weather Events in the Andes | Frontiers in Earth Science | Poveda, G.; Espinoza, J.; Zuluaga, M.; Solman, S.; Garreaud, R.; van Oevelen, P. | 2020 | Agua y Extremos | 10.3389/feart.2020.00162 | https://www.frontiersin.org/article/10.3389/feart.2020.00162/full | 162 | Vol: 8 | 2296-6463 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Owing to the extraordinary latitudinal extent, a strong orographic variability with very high mountain tops, and the presence of deep valleys and steep slopes, the Andes and the population of the region are highly prone and vulnerable to the impacts of a large suite of extreme weather events. Here we provide a review of the most salient events in terms of losses of human and animal lives, economic and monetary losses in costs and damages, and social disruption, namely: (1) extreme precipitation events and related processes (Mesoscale Convective Systems, lightning), (2) cold spells, frosts, and high winds, (3) the impacts of ENSO on extreme hydro-meteorological events, (4) floods, (5) landslides, mudslides, avalanches, and (6) droughts, heat waves and fires. For our purposes, we focus this review on three distinctive regions along the Andes: Northern tropical (north of 8°S), Southern tropical (8°S-27°S) and Extratropical Andes (south of 27°S). Research gaps are also identified and discussed at the end of this review. It is very likely that climate change will increase the vulnerability of the millions of inhabitants of the Andes, impacting their livelihoods and the sustainable development of the region into the twenty first century amidst urbanization, deforestation, air, soil and water pollution, and land use changes. |
| Local Perceptions of Fires Risk and Policy Implications in the Hills of Valparaíso, Chile | Sustainability | Sapiains, R.; Ugarte, A.; Aldunce, P.; Marchant, G.; Romero, J.; González, M.; Inostroza-Lazo, V. | 2020 | Agua y Extremos; Cambio de Uso de Suelo; Gobernanza e Interfaz Ciencia y Política | 10.3390/su12104298 | https://www.mdpi.com/2071-1050/12/10/4298 | 4298 | Vol: 12 Issue: 10 | 2071-1050 | Thomson Reuters ISI (SCIE; SSCI) | All Open Access; Gold Open Access | English | Climate change is increasing the occurrence of natural disasters worldwide, and more frequent and intense fires represent one of the most destructive expressions of this trend. Chile is highly vulnerable to climate change, and fires are a recurrent phenomenon affecting many people each year. To reduce fire risk, the Intergovernmental Panel on Climate Change (IPCC) suggests reducing both exposure and vulnerability through multiple initiatives, which demand increased community engagement. In such a context, this study explores local perceptions of fire in a sample of inhabitants in a wildland-urban interface (WUI) in Valparaiso, a city that is affected by numerous fires each year. The ultimate goal was to identify psychological and community factors that should be taken into consideration to develop prevention plans and safer environments for people living in a context of poverty and social inequity. Using a qualitative approach, 28 interviews were conducted and analyzed following grounded theory principles. Results identified multiple causes, impacts, and characteristics of the problem perceived by people who permanently cohabit with fire risk, showing that for many of them, fire risk is not about the probability of occurrence of a disaster, but a question about when and how the next fire will happen. However, in such a complex scenario, psychological, community, and structural barriers deter people from implementing more effective actions. Conversely, in emergency situations, such barriers are irrelevant and cooperative actions prevail, suggesting the existence of resources and capacities within the community that could lessen exposure and vulnerability if activated on a day-to-day basis. Overall, reducing fire risk cannot be achieved by local communities alone nor without their support. To build, maintain, and consolidate fire prevention actions, it is critical to activate community strengths and cooperation and engage the resources and management capacity of local governments. |
| Recent changes in the precipitation-driving processes over the southern tropical Andes/western Amazon | Climate Dynamics | Segura, H.; Espinoza, J.; Junquas, C.; Lebel, T.; Vuille, M.; Garreaud, R. | 2020 | Agua y Extremos | 10.1007/s00382-020-05132-6 | http://link.springer.com/10.1007/s00382-020-05132-6 | 2613-2631 | Vol: 54 | 0930-7575, 1432-0894 | Thomson Reuters ISI (SCIE) | | English | Analyzing December–February (DJF) precipitation in the southern tropical Andes—STA (12∘S–20∘S; > 3000 m.a.s.l) allows revisiting regional atmospheric circulation features accounting for its interannual variability over the past 35 years (1982–2018). In a region where in-situ rainfall stations are sparse, the CHIRPS precipitation product is used to identify the first mode of interannual DJF precipitation variability (PC1-Andes). A network of 98 rain-gauge stations further allows verifying that PC1-Andes properly represents the spatio-temporal rainfall distribution over the region; in particular a significant increase in DJF precipitation over the period of study is evident in both in-situ data and PC1-Andes. Using the ERA-Interim data set, we found that aside from the well-known relationship between precipitation and upper-level easterlies over the STA, PC1-Andes is also associated with upward motion over the western Amazon (WA), a link that has not been reported before. The ascent over the WA is a component of the meridional circulation between the tropical North Atlantic and western tropical South America—WTSA (80∘W–60∘W; 35∘S–10∘N). Indeed, the precipitation increase over the last 2 decades is concomitant with the strengthening of this meridional circulation. An intensified upward motion over the WA has moistened the mid-troposphere over WTSA, and as a consequence, a decreased atmospheric stability between the mid- and the upper troposphere is observed over this region, including the STA. We further show that, over the last 15 years or so, the year-to-year variability of STA precipitation (periodicity < 8 years) has been significantly associated with upward motion over the WA, while upper-level easterlies are no longer significantly correlated with precipitation. These observations suggests that the STA have experienced a transition from a dry to a wet state in association with a change in the dominant mode of atmospheric circulation. In the former dominant state, zonal advection of momentum and moisture from the central Amazon, associated with upper-level easterlies, is necessary to develop convection over the STA. Since the beginning of the 21st century, DJF precipitation over the STA seems to respond directly and primarily to upward motion over the WA. Beyond improving our understanding of the factors influencing STA precipitation nowadays, these results point to the need of exploring their possible implications for the long-term evolution of precipitation in a context of global warming. |
| Tree-growth at the rear edge of a Nothofagus pumilio Andean forest from Northern Patagonia show different patterns and a decline in the common signal during the last century | Forest Ecology and Management | Serrano-León, H.; Christie, D. | 2020 | Agua y Extremos | 10.1016/j.foreco.2020.118426 | https://linkinghub.elsevier.com/retrieve/pii/S0378112720311956 | 118426 | Vol: 475 | 03781127 | Thomson Reuters ISI (SCIE) | | English | Nothofagus pumilio is the dominant tree species at high elevations in the southern Andes between 35° and 55° S. Despite the number of tree-growth studies on this tree species, there is scarce information about the growth patterns and its relation with climatic variability at its lower elevation margin of distribution in the windward side of the Andes. In this study we focus on the altitudinal rear edge of a N. pumilio forest growing on the Pacific side of the northern Patagonian Andes to determine the main temporal patterns of tree radial growth, identify its relations with regional and large-scale climate and to assess the temporal variation of common signal in tree growth at centennial time-scales.
A Principal Component Analysis (PCA) between trees for their common period 1850–2010 indicates the existence of more than one pattern of tree growth within this lower altitudinal margin, which exhibit contrasting relations with climate. The tree ring chronology and the PC1 amplitude of tree growth shows negative correlation with maximum temperature during spring-summer while the PC2 shows the contrary. Maps and correlation functions indicate that the PC1 and PC2 patterns of N. pumilio growth are significantly related with high latitude climate variability induced by the Antarctic Oscillation (AAO) during spring-summer in an opposite manner, with the PC1 (PC2) negatively (positively) correlated with the poleward displacement of the storm tracks driven by the mid- and high-latitude dipole pressure in the Southern Hemisphere. The running PCA between the standardized tree ring-width series shows a decreasing trend in the percentage of variance explained by the first mode of tree growth, indicating a centennial scale loss in the common signal of growth within the population, especially since mid-20th century when the behavior of the AAO was unprecedented within the context of the last millennium.
Given that the future climatic scenario for northern Patagonia as predicted by models would led to more arid conditions forced by the positive trend of the AAO, we expect that the main pattern of N. pumilio growth at the rear edge of Choshuenco volcano will be negatively affected. Despite the present knowledge about N. pumilio radial growth in treeline environments, specific research is needed to gain insights about the complexity of the climate-growth relationship at its low elevation margin, in order to evaluate anomalies in tree growth patterns in the habitat where N. pumilio grows and competes with other low elevation species more tolerant to warmer conditions. |
| Environmental costs of water transfers | Nature Sustainability | Vargas, C.; Garreaud, R.; Barra, R.; Vásquez-Lavin, F.; Saldías, G.; Parra, O. | 2020 | Agua y Extremos | 10.1038/s41893-020-0526-5 | http://www.nature.com/articles/s41893-020-0526-5 | 408-409 | Vol: 3 Issue: 6 | 2398-9629 | Thomson Reuters ISI (SCIE; SSCI) | | English | Central Chile (30–37° S) is home to ∼10 million inhabitants and hosts intensive agriculture, mining, forestry and electricity generation. These activities are already constrained by limited freshwater availability in this semi-arid region that has been regularly affected by short-lived (<3 years) but intense (>50% rainfall deficit) droughts in the past. More recently, a large portion of this territory has experienced a megadrought, an uninterrupted sequence of dry years since 2010, partially driven by climate change1. Model-based climate projections for the rest of twenty-first century suggest a poleward expansion of the Hadley cell and the arid belt, thus causing further warming and drying across most of Mediterranean regions of the world, including central Chile, southern Africa and parts of western North America and Australia. Under a heavy carbon emission scenario, annual precipitation in central Chile would reduce by up to 30%, and mean temperature would increase up to 2.5 °C2. These trends would further decrease freshwater availability. The present and future acute shortages in freshwater access in different regions worldwide, such as in central Chile, have led some private initiatives to propose water diversion from the more humid south-central part of the country (Fig. 1). These ‘hydrological roads’ involve large-scale capture, storage and transfer of freshwater across 2,000 km. One argument to justify such proposals in different regions of the planet is that freshwater is wasted when it reaches the sea. However, many studies recognize that riverine influxes of organic matter and nutrients exported from rivers are extremely important for supporting coastal biological productivity and biogeochemical cycles3. For instance, the Maule, Rapel and Biobío rivers in Chile export hundreds of tons of nitrogen, and thousands of tons of silicon and carbon4 daily, which could contribute to a significant fraction of the high fish biomass typically recorded along Chilean coast. |
| Geo-climatic hazards in the eastern subtropical Andes: distribution, climate drivers and trends | Natural Hazards and Earth System Sciences | Vergara, I.; Moreiras, S.; Araneo, D.; Garreaud, R. | 2020 | Agua y Extremos | 10.5194/nhess-20-1353-2020 | https://www.nat-hazards-earth-syst-sci.net/20/1353/2020/ | 1353-1367 | Vol: 20 Issue: 5 | 1684-9981 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access; Green Open Access | English | Detecting and understanding historical changes in the frequency of geo-climatic hazards (G-CHs) is crucial for the quantification of current hazards and project them into the future. Here we focus in the eastern subtropical Andes (32–33∘ S), using meteorological data and a century-long inventory of 553 G-CHs triggered by rainfall or snowfall. We first analyse their spatio-temporal distributions and the role of climate
variability in the year-to-year changes in the number of days per season
with G-CHs. Precipitation is positively correlated with the number of G-CHs
across the region and year-round; mean temperature is negatively correlated
with snowfall-driven hazards in the western (higher) half of the study
region during winter and with rainfall-driven hazards in the eastern zone
during summer. The trends of the G-CH frequency since the mid-20th century
were calculated, paying attention to their non-systematic monitoring. The
G-CH series for the different triggers, zones and seasons were generally
stationary. Nonetheless, there is a small positive trend in rainfall-driven
G-CHs in the eastern zone during summer, congruent with a rainfall increase
there. We also found a decrease in snowfall-driven G-CHs in the western zone from the late 1990s onwards, most likely due to a reduction in winter precipitation rather than to an increase in temperature. |
| The glass half-empty: climate change drives lower freshwater input in the coastal system of the Chilean Northern Patagonia | Climatic Change | Aguayo, R.; León-Muñoz, J.; Vargas-Baecheler, J.; Montecinos, A.; Garreaud, R.; Urbina, M.; Soto, D.; Iriarte, J. | 2019 | Agua y Extremos | 10.1007/s10584-019-02495-6 | http://link.springer.com/10.1007/s10584-019-02495-6 | 417-435 | Vol: 155 Issue: 3 | 0165-0009 | Thomson Reuters ISI (SCIE) | | English | Oceanographic conditions in coastal Chilean northern Patagonia (41–46°S) are strongly influenced by freshwater inputs. Precipitation and streamflow records have shown a marked decrease in this area during the last decades. Given this hydro-climatic scenario, we evaluated the hydrological sensitivity driven by climate change in the Puelo River (average annual streamflow = 640 m³ s⁻¹), one of the most important sources of freshwater in the fjords and inland seas of Chile’s Northern Patagonia. A lumped hydrological model was developed to evaluate the potential impacts of climate change under the Representative Concentration Pathways (RCP) 2.6, 4.5, and 8.5 scenarios in the near future (2030–2060) using the delta change method based on 25 General Circulation Models. The model was fed by local hydro-meteorological data and remote sensors, simulating well the magnitude and seasonality of Puelo River streamflow. Considering the Refined Index of Agreement (RIA), the model achieved a high performance in the calibration (RIA = 0.79) and validation stages (RIA = 0.78). Under the RCP 8.5 scenario (multi-model mean), the projections suggest that the annual input of freshwater from the Puelo River to the Reloncaví Fjord would decrease by − 10% (1.6 km³ less freshwater); these decreases would mainly take place in summer (~ − 20%) and autumn (~ − 15%). The recurrence of extreme hydroclimatic events is also projected to increase in the future, with the probability of occurrence of droughts, such as the recent 2016 event with the lowest freshwater input in the last 70 years, doubling with respect to the historical records. |
| Role of synoptic activity on projected changes in upwelling-favourable winds at the ocean’s eastern boundaries | npj Climate and Atmospheric Science | Aguirre, C.; Rojas, M.; Garreaud, R.; Rahn, D. | 2019 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | 10.1038/s41612-019-0101-9 | http://www.nature.com/articles/s41612-019-0101-9 | 44 | Vol: 2 Issue: 1 | 2397-3722 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The climate of the ocean’s eastern boundaries is strongly influenced by subtropical anticyclones, which drive a surface wind stress that promotes coastal upwelling of nutrient-rich subsurface water that supports high primary productivity and an abundance of food resources. Understanding the projected response of upwelling-favourable winds to climate change has broad implications for coastal biogeochemistry, ecology, and fisheries. Here we use a reanalysis, an ensemble of global climate simulations, and an objective algorithm to track anticyclones to investigate the projected changes in upwelling-favourable wind events at the California, Canary, Humboldt, and Benguela coastal upwelling systems. Except for the north Pacific, we find consistent poleward shifts of mean and upper percentile daily winds over the ocean basins. We propose that extratropical, synoptic-scale migratory anticyclones that force intense coastal upwelling events—which become more frequent at higher latitudes and less frequent at lower latitudes in the future—play an important role in the projected changes in upwelling-favourable wind events in these coastal upwelling systems. These changes complement large-scale processes such as the poleward shift of the subtropical ridge (STR) and stationary subtropical highs. Hence, both extratropical and tropical processes need to be considered to fully explain projected changes at the coastal upwelling systems under anthropogenic climate change. |
| TRANSFORMACIÓN: Grandes desafíos - Profundos cambios | | Aldunce, P. | 2019 | Agua y Extremos | | https://www.cr2.cl/transformacion-grandes-desafios-profundos-cambios/ | | | | cr2.cl | | | El planeta está experimentando rápidos cambios, a una velocidad sin precedentes. En una
sola generación, los humanos nos hemos convertido en una enorme fuerza global, somos
parte de esta historia, hemos construido tanto el pasado, como el presente del planeta, somos
responsables, pero esta responsabilidad no puede ser un motivo para la inacción, sino más
bien un llamado a la acción, con esperanza de escribir un mejor futuro para el planeta. Para enfrentar el futuro, no es suficiente responder con cambios menores o incrementales, los cuales
a pesar de que han sido necesarios, no son suficientes. Hay una necesidad, urgencia y oportunidad de explorar más allá, utilizando el enfoque de la Transformación, para realizar cambios a
mayor escala y más profundos. Es importante considerar que los enfoques incrementales y los
transformacionales son complementarios, no compiten.
Los procesos transformacionales siempre han existido, ya que la transformación es un proceso
inherente a la sociedad. Por otro lado, la ciencia ha logrado grandes avances en la aproximación de la transformación a lo largo de distintas disciplinas, sin embargo, en muchos casos,
los conocimientos científico y práctico han evolucionado independientemente. El presente
documento aborda la temática de la transformación, siendo un documento de resumen, que
pueda ser de utilidad tanto para investigadores como otros actores sociales, que estén interesados en utilizar la perspectiva de la transformación, como un enfoque válido para responder
a las crecientes demandas que emergen para enfrentar el cambio climático. |
| Comité Científico COP25: Criósfera y Cambio Climático 50 preguntas y respuestas | | Aldunce, P.; Andrade, C.; Anicama, J.; Arana, P.; Azócar, G.; Cabrol, L.; Carrasco, J.; Casanova-Katny, A.; Cavieres, L.; Cereceda-Balic, F.; Christie, D.; Cid-Agüero, P.; Cordero, R.; Crespo, S.; Damiani, A.; Dussaillant-Jones, A.; Fernández, A.; Fernández, C.; Fernandoy, F.; Frangopulos, M.; Fuent... | 2019 | Agua y Extremos; Ciudades Resilientes | | https://www.minciencia.gob.cl/comitecientifico/documentos/mesa-criosfera-y-antartica/12.Criosfera-y-cambio-climatico.pdf | | | | | | | La criósfera comprende las partes de la Tierra donde encontramos agua en estado sólido: nieve, glaciares, hielo marino, mantos de hielo y suelos congelados (permafrost). El territorio chileno posee todos estos componentes, pero de ellos, los más relevantes son los glaciares, con alrededor de 24 000 km2 (3 % del área mundial). Sin embargo, los glaciares están en franco retroceso debido al cambio climático. Su distribución varía con la altitud y latitud, con un gradiente desde los Andes Norte y Centro (4.4 %), a la región centro-sur (6.2 %) hasta alcanzar su mayor extensión en la zona de la Patagonia y Tierra del Fuego (89.3 %). La pérdida de masa de hielo en la cordillera de los Andes ha sido de 23 gigatoneladas en los últimos veinte años. Preocupante aspecto, por ser el recurso agua uno de los que está más amenazado actualmente en la zona centro-norte del país. En el marco del cambio climático, la Antártica presenta procesos antagónicos y sinérgicos. Las aguas muy frías del océano tienen una gran capacidad para exportar carbono desde la atmósfera y ejercer un importante control sobre el clima regional y global. No obstante, el calentamiento global está derritiendo una parte de la cobertura de hielo, lo cual libera el hierro atrapado en su interior y potencia la productividad y exportación de carbono al fondo del océano (que estaba originalmente como CO2 en la atmósfera). Sin embargo, esta capacidad del océano de capturar CO2 se contrapone con el riesgo de incrementar su acidificación. |
| Comité Científico COP25: Transformación: Un tema emergente en la adaptación al cambio climático en Chile. Informe de la mesa de Adaptación | | Aldunce, P.; Vicuña, S. | 2019 | Agua y Extremos | | https://www.minciencia.gob.cl/comitecientifico/documentos/mesa-adaptacion/5.Transformacion-Un-tema-emergente-en-la-adaptacion-al-cambio-climatico-en-Chile.pdf | | | | | | | La transformación es una de las temáticas que está emergiendo en el ámbito del cambio climático en Chile. Uno de los aspectos más relevantes es promover la alfabetización del enfoque transformacional, con especial énfasis en sus modos de implementación, ya que se reconoce cierta desinformación y confusión respecto de la transformación. En particular en el caso de organizaciones gubernamentales, se recomienda comenzar su inclusión de forma explícita en las discusiones, toma de decisiones e instrumentos de política pública. Se denota una urgencia asociada a la transformación debido a la necesidad de actuar y planificar hoy para: i) hacer frente a los impactos actuales, por ejemplo, aquellos producidos por eventos climáticos extremos; ii) obtener resultados en el futuro, reforzando la visión de largo plazo, como es el caso de la Estrategia de Largo Plazo para un Desarrollo Bajo en Emisiones (ELP) del Acuerdo de París; y iii) anticiparse a los impactos futuros, en especial si se cuenta con proyecciones climáticas, para lograr una mayor probabilidad de transformaciones positivas. |
| Comité Científico COP25: Adaptación al cambio climático en Chile: Brechas y recomendaciones. Informe de las mesas Adaptación y Agua. | | Aldunce, P.; Vicuña, S. | 2019 | Agua y Extremos | | https://www.minciencia.gob.cl/comitecientifico/documentos/mesa-adaptacion/1.Adaptacion-Brechas-Aldunce.pdf | | | | | | | El presente informe se estructura en tres secciones. Primero, se presentan las necesidades de implementación de medidas de adaptación en un contexto global y a nivel nacional. Segundo, se hace una revisión crítica de la situación actual del uso de instrumentos públicos para la implementación de la adaptación al cambio climático en Chile. Tercero, en este análisis se entregan algunas brechas relevantes. Por último, se presenta una sección en la que se plantean una serie de desafíos y recomendaciones para mejorar la implementación de la adaptación en Chile. Sus principales mensajes son que existe consenso científico en que el cambio climático es un hecho y que en gran parte ha sido causado por la actividad antrópica. El cambio climático posee múltiples impactos en la actualidad y se espera que aumenten en el futuro. Como segundo mensaje, se concluye que Chile es un país altamente vulnerable al cambio climático. Uno de sus principales impactos es la disminución en la disponibilidad de recursos hídricos producto de la reducción en precipitación, aumento en temperatura y el derretimiento acelerado de la criósfera. Además, existen impactos asociados a otras amenazas de origen climático, como los aluviones, marejadas, incendios y olas de calor, entre otras. El cambio climático afecta de forma diferente a la población, la infraestructura y los sistemas naturales en función de una vulnerabilidad diferenciada. La adaptación emerge como una posibilidad real de aumentar la resiliencia y reducir la vulnerabilidad de estos sistemas. Nuestro país ha avanzado en el diseño e implementación de políticas públicas de adaptación. Sin embargo, existen reales posibilidades de mejoras a lo ya hecho en términos de diseño, implementación y seguimiento de Planes de Adaptación al Cambio Climático (PACC), así como también en la ambición de compromisos de las Contribuciones Determinadas a nivel Nacional (NDC). El mensaje final de este informe se basa en recomendaciones de mejoras en estos temas. |
| The Impacts of Native Forests and Forest Plantation on Water Supply in Chile | Forests | Alvarez-Garreton, C.; Lara, A.; Boisier, J.; Galleguillos, M. | 2019 | Agua y Extremos; Cambio de Uso de Suelo | 10.3390/f10060473 | https://www.mdpi.com/1999-4907/10/6/473 | 473 | Vol: 10 Issue: 6 | 1999-4907 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Over the past 40 years, south-central Chile has experienced important land-use-induced land cover changes, with massive conversion from native forests (NF) to Pinus radiata D.Don and Eucalyptus spp. exotic forest plantations (FP). Several case studies have related this conversion to a reduction in water supply within small catchments (<100 ha). In this work, we explore the impacts of NF and FP on streamflow by using a large-sample catchment dataset recently developed for Chile. We select 25 large forested catchments (>20,000 ha) in south-central Chile (35° S–41° S), analyze their land cover and precipitation spatial distributions, and fit a regression model to quantify the influence of NF, FP, grassland (GRA) and shrubland (SHR) partitions on annual runoff. To assess potential effects of land cover changes on water supply, we use the fitted model (R2 = 0.84) in synthetic experiments where NF, GRA and SHR covers within the catchments are replaced by patches of FP. We show that annual runoff consistently decreases with increments of FP, although the magnitude of the change (ranging from 2.2% to 7.2% mean annual runoff decrease for 10,000 ha increment in FP) depends on several factors, including the initial land cover partition within the basin, the replaced land cover class, the area of the catchment, and the type of catchment (drier or humid). Finally, in the context of the mitigation strategies pledged in the Chilean NDC (Nationally Determined Contributions defined after the Paris Agreement), which include the afforestation of 100,000 ha (mainly native forest) by 2030, we quantify the impacts on water supply due to the afforestation of 100,000 ha with different combinations of NF and FP. We show that annual runoff is highly sensitive to the relative area of FP to NF: ratios of FP to NF areas of 10%, 50% and 90% would lead to 3%, −18% and −40% changes in mean annual runoff, respectively. Our results can be used in the discussion of public policies and decision-making involving forests and land cover changes, as they provide scientifically-based tools to quantify expected impacts on water resources. In particular, this knowledge is relevant for decision making regarding mitigation strategies pledged in the Chilean NDC. |
| Anthropocene and streamflow: Long-term perspective of streamflow variability and water rights | Elementa: Science of the Anthropocene | Barria, P.; Rojas, M.; Moraga, P.; Muñoz, A.; Bozkurt, D.; Alvarez, C. | 2019 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.1525/elementa.340 | https://www.elementascience.org/article/10.1525/elementa.340/ | 2 | Vol: 7 Issue: 1 | 2325-1026 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Since 1981, water allocation in Chile has been based on a water use rights (WURs) market, with limited regulatory and supervisory mechanisms. The volume to be granted as permanent and eventual WURs is calculated from streamflow records, if stream gauge data are available, or from hydrologic parameter transfer from gauged to ungauged catchments, usually with less than 50 years of record. To test the per- formance of this allocation system, while analyzing the long-term natural variability in water resources, we investigated a 400 year-long (1590–2015) tree-ring reconstruction of runoff and historical water rights for Perquilauquén at Quella catchment, a tributary to the Maule River in Central Chile (35°S–36°30S). Furthermore, we assess how the current legislation would perform under a projected climate scenario, based on historical climate simulations of runoff calibrated against observed data, and future projections. Our analyses indicate that the allocation methodology currently applied by the Water Authority in Chile is very sensitive to the time window of data used, which leads to an underestimation of variability and long-term trends. According to the WURs database provided by the Chilean Water Directorate, WURs at Perquilauquén at Quella are already over-allocated. Considering regional climate projections, this condition will be exacerbated in the future. Furthermore, serious problems regarding the access and quality of infor- mation on already-granted WURs and actual water usage have been diagnosed, which further encumber environmental strategies to deal with and adapt to climate change. We emphasize the urgent need for a review and revision of current water allocation methodologies and water law in Chile, which are not concordant with the dynamics and non-stationarity of hydrological processes. Water scarcity and water governance are two of the key issues to be faced by Chile in the Anthropocene. |
| The Role of Streamside Native Forests on Dissolved Organic Matter in Forested and Agricultural Watersheds in Northwestern Patagonia | Forests | Becerra-Rodas, C.; Little, C.; Lara, A.; Sandoval, J.; Osorio, S.; Nimptsch, J. | 2019 | Agua y Extremos; Cambio de Uso de Suelo | 10.3390/f10070595 | https://www.mdpi.com/1999-4907/10/7/595 | 595 | Vol: 10 Issue: 7 | 1999-4907 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Streamside native forests are known for their key role in water provision, commonly referred to as buffers that control the input or output of nutrients from terrestrial to aquatic ecosystems (i.e., nitrogen or carbon cycle). In order to assess the functional role of indigenous forests along streamside channels, we measured 10 parameters associated with DOM (Dissolved Organic Matter) at 42 points in 12 small catchments (15–200 ha) dominated by native forests (reference, WNF), forest plantations (WFP) and agricultural lands (WAL) in which the land cover portion was calculated in the entire watershed and along 30 and 60-m wide buffer strips. We found that watersheds WFP and WAL were statistically different than WNF, according to DIC concentrations (Dissolved Inorganic Carbon) and the intensity of the maximum fluorescence of DOM components. Using linear models, we related streamside native forest coverage in buffer strips with DOM parameters. The increase of streamside native forest coverage in 60 m wide buffer strips (0–100%) was related to lower DIC concentrations (0.89 to 0.28 mg C L−1). In watersheds WFP and WAL, the humic and fulvic-like components (0.42 to 1.42 R.U./mg C L−1) that predominated were related to an increase in streamside native forest coverage in the form of a 60 m wide buffer strip (0–75%). This is evidence that streamside native forests influence outputs of detritus and lowered in-stream processing with concomitant downstream transport, and functional integrity and water quality. We propose that DOM quantity and quality may be a potential tool for the identification of priority areas near streams for conservation and ecological restoration in terms of recovery of water quality as an important ecosystem service. The results of this study are useful to inform policy and regulations about the width of streamside native forests as well as their characteristics and restrictions. |
| Human–environmental drivers and impacts of the globally extreme 2017 Chilean fires | Ambio | Bowman, D.; Moreira-Muñoz, A.; Kolden, C.; Chávez, R.; Muñoz, A.; Salinas, F.; González-Reyes, Á.; Rocco, R.; de la Barrera, F.; Williamson, G.; Borchers, N.; Cifuentes, L.; Abatzoglou, J.; Johnston, F. | 2019 | Agua y Extremos | 10.1007/s13280-018-1084-1 | http://link.springer.com/10.1007/s13280-018-1084-1 | 350–362 | Vol: 48 | 0044-7447 | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | In January 2017, hundreds of fires in Mediterranean Chile burnt more than 5000 km2, an area nearly 14 times the 40-year mean. We contextualize these fires in terms of estimates of global fire intensity using MODIS satellite record, and provide an overview of the climatic factors and recent changes in land use that led to the active fire season and estimate the impact of fire emissions to human health. The primary fire activity in late January coincided with extreme fire weather conditions including all-time (1979–2017) daily records for the Fire Weather Index (FWI) and maximum temperature, producing some of the most energetically intense fire events on Earth in the last 15-years. Fire activity was further enabled by a warm moist growing season in 2016 that interrupted an intense drought that started in 2010. The land cover in this region had been extensively modified, with less than 20% of the original native vegetation remaining, and extensive plantations of highly flammable exotic Pinus and Eucalyptus species established since the 1970s. These plantations were disproportionally burnt (44% of the burned area) in 2017, and associated with the highest fire severities, as part of an increasing trend of fire extent in plantations over the past three decades. Smoke from the fires exposed over 9.5 million people to increased concentrations of particulate air pollution, causing an estimated 76 premature deaths and 209 additional admissions to hospital for respiratory and cardiovascular conditions. This study highlights that Mediterranean biogeographic regions with expansive Pinus and Eucalyptus plantations and associated rural depopulation are vulnerable to intense wildfires with wide ranging social, economic, and environmental impacts, which are likely to become more frequent due to longer and more extreme wildfire seasons. |
| Dynamical downscaling over the complex terrain of southwest South America: present climate conditions and added value analysis | Climate Dynamics | Bozkurt, D.; Rojas, M.; Boisier, J.; Rondanelli, R.; Garreaud, R.; Gallardo, L. | 2019 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | 10.1007/s00382-019-04959-y | http://link.springer.com/10.1007/s00382-019-04959-y | 6745-6767 | Vol: 53 Issue: 11 | 0930-7575 | Thomson Reuters ISI (SCIE) | | English | This study evaluates hindcast simulations performed with a regional climate model (RCM, RegCM4) driven by reanalysis data (ERA-Interim) over the Pacific coast and Andes Cordillera of extratropical South America. A nested domain configuration at \(0.44^{\circ }\) ( \(\sim\) 50 km) and \(0.09^{\circ }\) ( \(\sim\) 10 km) spatial resolutions is used for the simulations. RegCM4 is also driven by a global climate model (GCM, MPI-ESM-MR) on the same domain configuration to asses the added values for temperature and precipitation (historical simulations). Overall, both 10 km hindcast and historical simulation results are promising and exhibit a better representation of near-surface air temperature and precipitation variability compared to the 50 km simulations. High-resolution simulations suppress an overestimation of precipitation over the Andes Cordillera of northern Chile found with the 50 km simulations. The simulated daily temperature and precipitation extreme indices from 10 km hindcast simulation show a closer estimation of the observed fields. A persistent warm bias ( \(\sim +\,{4\,}^{\circ }\hbox {C}\) ) over the Atacama Desert in 10 km hindcast simulation reveals the complexity in representing land surface and radiative processes over the desert. Difficulties in capturing the temperature trend in northern Chile are notable for both hindcast simulations. Both resolutions exhibit added values for temperature and precipitation over large parts of Chile, in particular, the 10 km resolves the coastal-valley Andes transitions over central Chile. Our results highlight that resolutions coarser than 50 km (e.g., GCMs and reanalysis) miss important climate gradients imposed by complex topography. Given that the highest spatial resolution of the current regional simulations over the South America is about 50 km, higher resolutions are important to improve our understanding of the dynamical processes that determine climate over complex terrain and extreme environments. |
| Informe de Síntesis Simulaciones climáticas regionales para el continente Antártico | | Bozkurt, D.; Rondanelli, R.; Carrasco, J.; Boisier, J.; Morales, B.; Muñoz, F.; Valdebenito, N.; Del Hoyo, M.; Troncoso, M.; Bustos, S. | 2019 | Agua y Extremos; Zonas Costeras | | https://cambioclimatico.mma.gob.cl/wp-content/uploads/2020/05/Informe-sintesis-simulacionesantartica.pdf | | | | | | | |
| Informe de Síntesis Simulaciones climáticas regionales para el territorio insular Chileno | | Bozkurt, D.; Rondanelli, R.; Carrasco, J.; Boisier, J.; Morales, B.; Muñoz, F.; Valdebenito, N.; Del Hoyo, M.; Troncoso, M.; Bustos, S. | 2019 | Agua y Extremos; Zonas Costeras | | https://cambioclimatico.mma.gob.cl/wp-content/uploads/2020/05/Informe-sintesis-simulaciones-territorio-insular.pdf | | | | | | | |
| Comentarios Centro de Ciencia del Clima y la Resiliencia (CR)2 a la consulta ciudadana de primera actualización 2019 de la Contribución Determinada a Nivel Nacional (NDC) de Chile. Diciembre 2019 | | Centro de Ciencia del Clima y la Resiliencia (CR)2 | 2019 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2019/12/Resumen-Comentarios-CR2_NDC-2019_02122019.pdf | | | | | | | |
| A Multiscale Productivity Assessment of High Andean Peatlands across the Chilean Altiplano Using 31 Years of Landsat Imagery | Remote Sensing | Chávez, R.; Christie, D.; Olea, M.; Anderson, T. | 2019 | Agua y Extremos | 10.3390/rs11242955 | https://www.mdpi.com/2072-4292/11/24/2955 | 2955 | Vol: 11 Issue: 24 | 2072-4292 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access; Green Open Access | English | The high Andean peatlands, locally known as “bofedales”, are a unique type of wetland distributed across the high-elevation South American Altiplano plateau. This extensive peatland network stores significant amounts of carbon, regulates local and regional hydrological cycles, supports habitats for a variety of plant and animal species, and has provided critical water and forage resources for the livestock of the indigenous Aymara communities for thousands of years. Nevertheless, little is known about the productivity dynamics of the high Andean peatlands, particularly in the drier western Altiplano region bordering the Atacama desert. Here, we provide the first digital peatland inventory and multiscale productivity assessment for the entire western Altiplano (63,705 km2) using 31 years of Landsat data (about 9000 scenes) and a non-parametric approach for estimating phenological metrics. We identified 5665 peatland units, covering an area of 510 km2, and evaluated the spatiotemporal productivity patterns at the regional, peatland polygon, and individual pixel scales. The regional assessment shows that the peatland areas and peatlands with higher productivity are concentrated towards the northern part of our study region, which is consistent with the Altiplano north–south aridity gradient. Regional patterns further reveal that the last seven years (2011–2017) have been the most productive period over the past three decades. While individual pixels show contrasting patterns of reductions and gains in local productivity during the most recent time period, most of the study area has experienced increases in annual productivity, supporting the regional results. Our novel database can be used not only to explore future research questions related to the social, biological, and hydrological influences on peatland productivity patterns, but also to provide technical support for the sustainable development of livestock practices and conservation and water management policy in the Altiplano region. |
| GIMMS NDVI time series reveal the extent, duration, and intensity of “blooming desert” events in the hyper-arid Atacama Desert, Northern Chile | International Journal of Applied Earth Observation and Geoinformation | Chávez, R.; Moreira-Muñoz, A.; Galleguillos, M.; Olea, M.; Aguayo, J.; Latín, A.; Aguilera-Betti, I.; Muñoz, A.; Manríquez, H. | 2019 | Agua y Extremos; Cambio de Uso de Suelo | 10.1016/j.jag.2018.11.013 | https://linkinghub.elsevier.com/retrieve/pii/S0303243418306202 | 193-203 | Vol: 76 | 0303-2434 | Thomson Reuters ISI (SCIE) | | English | The “blooming desert”, or the explosive development and flowering of ephemeral herbaceous and some woody desert species during years with abnormally high accumulated rainfall, is a spectacular biological phenomenon of the hyper-arid Atacama Desert (northern Chile) attracting botanists, ecologists, geo-scientists, and the general public from all over the world. However, the number of “blooming deserts”, their geographical distribution and spatio-temporal patterns have not been quantitatively assessed to date. Here, we used NDVI data from the Global Inventory Modeling and Mapping Studies (GIMMS) project to reconstruct the annual land surface phenology (LSP) of the Atacama Desert using a non-parametric statistical approach. From the reconstructed LSP, we detected the “blooming deserts” as positive NDVI anomalies and assessed three dimensions of the events: their temporal extent, intensity of “greening” and spatial extent. We identified 13 “blooming deserts” between 1981 and 2015, of which three (1997–98, 2002–03, and 2011) can be considered major events according to these metrics. The main event occurred in 2011, spanning 180 days between July and December 2011, and spread over 11,136 km 2 of Atacama dry plains. “Blooming deserts” in Atacama have been triggered by the accumulation of precipitation during a period of 2 to 12 months before and during the events. The proposed three-dimensional approach allowed us to characterize different types of “blooming deserts”: with longer episodes or larger spatial distribution or with different “greening” intensities. Its flexibility to reconstruct different LSP and detect anomalies makes this method a useful tool to study these rare phenomena in other deserts in the world also. |
| Centennial‐Scale SE Pacific Sea Surface Temperature Variability Over the Past 2,300 Years | Paleoceanography and Paleoclimatology | Collins, J.; Lamy, F.; Kaiser, J.; Ruggieri, N.; Henkel, S.; De Pol‐Holz, R.; Garreaud, R.; Arz, H. | 2019 | Agua y Extremos; Cambio de Uso de Suelo | 10.1029/2018PA003465 | https://onlinelibrary.wiley.com/doi/abs/10.1029/2018PA003465 | 336-352 | Vol: 34 | 2572-4517 | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | Detailed temperature reconstructions over the past 2,000 years are important for contextualizing modern climate change. The midlatitude SE Pacific is a key region in this regard in terms of understanding the climatic linkages between the tropics and southern high latitudes. Multicentennial timescale temperature variability remains, however, poorly understood, due to a lack of long, high-temporal-resolution temperature records from this region and from the southern high latitudes in general. We present a unique alkenone sea surface temperature (SST) record from 44°S on the southern Chilean margin in the SE Pacific spanning the last 2,300 years at decadal resolution. The record displays relatively large changes including a cooling transition from 14 to 12.5 °C between 1,100 and 600 cal yr BP, in line with other Chile margin SST records and coeval with Antarctic cooling. This cooling is attributable to reduced Southern Ocean deep convection, driven by a late Holocene sea-ice increase in the Weddell Sea associated with increased El-Niño Southern Oscillation variability. Superimposed on the late Holocene cooling, we observe multicentennial timescale SST variability, including relatively cool SSTs (12.5 °C) from 950 to 500 cal yr BP, corresponding to the Medieval Climate Anomaly, and warmer SSTs (13 °C) from 500 to 200 cal yr BP, corresponding to the Little Ice Age. These oscillations may reflect either multicentennial internal variability of the Southern Ocean deep convection and/or multicentennial variability in the phasing of El-Niño Southern Oscillation and Southern Annular Mode events. ©2019. American Geophysical Union. All Rights Reserved. |
| Growth and steady state of the Patagonian Andes | American Journal of Science | Colwyn, D.; Brandon, M.; Hren, M.; Hourigan, J.; Pacini, A.; Cosgrove, M.; Midzik, M.; Garreaud, R.; Metzger, C. | 2019 | Agua y Extremos | 10.2475/06.2019.01 | http://www.ajsonline.org/lookup/doi/10.2475/06.2019.01 | 431-472 | Vol: 319 Issue: 6 | 0002-9599 | Thomson Reuters ISI (SCIE) | | English | Water isotopes are an important tool for reconstructing the amount of
atmospheric lifting related to high topography in the geologic past. However, our capacity for meaningful interpretation requires understanding the climatic setting and isolating the influence of orography on water isotopes. Patagonia’s simple, steady climatology and location within the Southern Westerlies makes it an ideal setting for successful application of water isotopes to measuring topography through time. Here we use hydrated volcanic glass to construct a new record of the size of the Patagonian Andes during the Cenozoic. We also utilize a novel method for identifying the contribution of orography in regional climate records. Our results show that variation in the observed record can largely be explained by variations in climate. Thus we conclude that the mountain range has maintained a size similar to modern since at least Paleocene. This result is in agreement with geologic data, which constrain the bulk of the surface uplift of the Andes to the Cretaceous. The reconstruction of the Patagonian Andes, which grew in the Cretaceous and remained high through the Cenozoic, is markedly different from the widely held view of Miocene formation of this mountain range. In particular, the topography appears to remain stable during the northward propagation and collision of offshore spreading centers. |
| Comité Científico COP25: Propuesta de un Sistema Integrado de Observación del Océano Chileno | | Farías, L.; Fernández, C.; Garreaud, R.; Guzmán, L.; Hormazábal, S.; Morales, C.; Narváez, D.; Pantoja, S.; Pérez, I.; Soto, D.; Winckler, P. | 2019 | Agua y Extremos; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2019/12/Propuesta-de-sistema-integrado-de-observación-del-océano.pdf | 1-27 | | | | | Spanish | Chile ocupa el décimo puesto a nivel mundial con mayor territorio marítimo y el primer lugar en Latinoamérica con mayor superficie de mar. El país es dependiente del océano en términos económicos, sociales y
culturales, que incluyen actividades en la zona costera y oceánica. Al mismo tiempo, los procesos climáticos
y oceanográficos constituyen constantes fuentes de riesgo e incertidumbre, aumentando la vulnerabilidad
en los socio-ecosistemas marinos. Chile está declarado un país altamente vulnerable al cambio climático,
basado en estudios derivados de la Agenda 2030 para el Desarrollo Sostenible de las Naciones Unidas. Esto
obliga a buscar propuestas y soluciones para abordar esta vulnerabilidad.
A nivel internacional, varios países han desarrollado e implementado sistemas integrados de observación
del océano basados en información continua sobre su estado y sus recursos, con el objetivo de abordar de
forma operacional la vulnerabilidad. Estos sistemas de observación tienen propósitos, tales como, mejorar la
seguridad en operaciones marinas, fortalecer la seguridad alimentaria, apoyar las actividades económicas de
pequeña y gran escala, reducir el riesgo frente a desastres naturales y disminuir la incertidumbre económica
junto con la conflictividad social y ambiental derivada de esta. El océano chileno está afecto a una serie de
procesos globales asociados al cambio climático, regionales y locales que necesitan, ser estudiados y monitoreados. Por lo tanto, se requiere de la existencia de un sistema de registro continuo de variables atmosféricas
y oceanográficas, que provea la información necesaria para la toma de decisiones, tanto públicas como privadas, y permita realizar análisis retrospectivos y predictivos del estado del océano.
Actualmente, existen en Chile algunas iniciativas de observación y monitoreo del océano, incluyendo
aportes de servicios públicos, instituciones académicas y organizaciones privadas. Sin embargo, estas no son
sistémicas y carecen de continuidad, principalmente por falta de instrumentos financieros de largo aliento y
de la valoración política de la información. En el compromiso nacional e internacional, el Comité Científico
COP25 releva la importancia de contar con información basada en la evidencia para planificar estratégicamente el desarrollo sostenible y la equidad intergeneracional respecto del uso y la conservación del océano,
de los ecosistemas marinos y sus servicios a la humanidad.
En este escenario, académicos, servidores públicos y agentes del sector privado con competencia en la
materia proponen gestar un Sistema Integrado de Observación del Océano Chileno (SIOOC), que permita
disponer de datos de calidad, estandarizados y de acceso público para el estudio, monitoreo, manejo y vigilancia del océano y sus recursos.
Se contemplan para la implementación del SIOOC, basado en la experiencia existente y las necesidades o
brechas del Chile, tres fases en un horizonte de 6 a 8 años:
› Primero, consolidar la integración de los sistemas existentes en una red asociativa y bajo una gobernanza apropiada, con recursos humanos y financiamiento de fuentes múltiples, e incluyendo
la participación del sector privado, productivo y de la sociedad civil.
› Segundo, incorporar al sistema de nuevos equipamientos e infraestructura (primario y secundario), con un análisis de las capacidades habilitantes y la transferencia tecnológica necesaria para
aumentar el tipo, número y cobertura de las observaciones, además de fortalecer las capacidades
de predicción.
› Tercero, incorporar en pleno del SIOOC a otras redes internacionales, especialmente en zonas de
alto interés, como la zona antártica, aguas internacionales e islas oceánicas.
Las universidades y los servicios del Estado participantes en esta propuesta comprometen la infraestructura y los conocimientos existentes para dar lanzamiento al SIOOC. A su vez, esperan que el Estado tome esta
iniciativa y un compromiso nacional e internacional como una acción para proteger nuestros mares. |
| Informe a las naciones: El Antropoceno en Chile: evidencias y formas de avanzar | | Gallardo, L.; Rudnick, A.; Barraza, J.; Fleming, Z.; Rojas, M.; Gayo, E.; Aguirre, C.; Farías, L.; Boisier, J.; Garreaud, R.; Barría, P.; Miranda, A.; Lara, A.; Gómez-González, S.; Arriagada, R. | 2019 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2019/06/Informe-Antropoceno-castellano.pdf | 40 | | | cr2.cl | | English | En el siglo XXI, el desarrollo de Chile está en juego debido a las amenazas planteadas por el Antropoceno. Esta época se caracteriza por la influencia humana sobre el sistema terrestre. Sin embargo, si se enfrenta con audacia, ofrece una oportunidad para un desarrollo sostenible. Independientemente de si hemos entrado en una nueva era geológica, el Antropoceno cuestiona nuestra forma de vivir en el planeta azul del sistema solar. O, dicho de otra manera, la forma de entender el progreso y el desarrollo. En un país con grandes desigualdades sociales, altamente vulnerable al cambio global, enfrentar este desafío es de crucial importancia y puede ofrecer nuevas oportunidades. |
| ¿Dónde esta lloviendo? Pregúntale a Vismet | Bits de Ciencias (DCC-UCH) | Garreaud, R.; Bastarrica, M. | 2019 | Agua y Extremos | | https://www.dcc.uchile.cl/Bitsdeciencia17.pdf | 8-13 | Issue: 17 | | | | Spanish | La meteorología es una ciencia que tiene dos
pilares. Uno de ellos es el conjunto de leyes
físicas de la atmósfera y otras componentes
del sistema terrestre. Su integración numérica
requiere grandes capacidades computacionales
y permite el pronóstico del tiempo ("forecasting")
hasta dos semanas en el futuro. El otro pilar
es el mundo de las observaciones, sin las
cuales no se podrían inicializar los modelos,
contrastar sus resultados y hacer sentido de
múltiples fenómenos atmosféricos. Más aún,
el pronóstico meteorológico de muy corto plazo
(0-6 horas) se basa mayormente en un tratamiento estadístico de las condiciones observadas actuales y pasadas. El así llamado "nowcasting" es de especial valor en condiciones
extremas; por ejemplo, para determinar si ocurrirá una crecida súbita en algún cajón cordillerano necesitamos saber qué está pasando
ahora en la cordillera. |
| Geohistorical records of the Anthropocene in Chile | Elem Sci Anth | Gayo, E.; McRostie, V.; Campbell, R.; Flores, C.; Maldonado, A.; Uribe-Rodriguez, M.; Moreno, P.; Santoro, C.; Christie, D.; Muñoz, A.; Gallardo, L. | 2019 | Agua y Extremos; Ciudades Resilientes | 10.1525/elementa.353 | https://www.elementascience.org/article/10.1525/elementa.353/ | 15 | Vol: 7 Issue: 1 | 2325-1026 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The deep-time dynamics of coupled socio-ecological systems at different
spatial scales is viewed as a key framework to understand trends and
mechanisms that have led to the Anthropocene. By integrating archeological
and paleoenvironmental records, we test the hypothesis that Chilean
societies progressively escalated their capacity to shape national
biophysical systems as socio-cultural complexity and pressures on natural
resources increased over the last three millennia. We demonstrate that
Pre-Columbian societies intentionally transformed Chile’s northern and
central regions by continuously adjusting socio-cultural practices and/or
incorporating technologies that guaranteed resource access and social
wealth. The fact that past human activities led to cumulative impacts on
diverse biophysical processes, not only contradicts the notion of pristine
pre-Industrial Revolution landscapes, but suggests that the Anthropocene
derives from long-term processes that have operated uninterruptedly since
Pre-Columbian times. Moreover, our synthesis suggests that most of
present-day symptoms that describe the Anthropocene are rooted in
pre-Columbian processes that scaled up in intensity over the last 3000
years, accelerating after the Spanish colonization and, more intensely, in
recent decades. The most striking trend is the observed coevolution between
the intensity of metallurgy and heavy-metal anthropogenic emissions. This
entails that the Anthropocene cannot be viewed as a universal imprint of
human actions that has arisen as an exclusive consequence of modern
industrial societies. In the Chilean case, this phenomenon is intrinsically
tied to historically and geographically diverse configurations in
society-environment feedback relationships. Taken collectively with other
case studies, the patterns revealed here could contribute to the discussion
about how the Anthropocene is defined globally, in terms of chronology,
stratigraphic markers and attributes. Furthermore, this deep-time narrative
can potentially become a science-based instrument to shape better-informed
discourses about the socio-environmental history in Chile. More importantly,
however, this research provides crucial “baselines” to delineate safe
operating spaces for future socio-ecological systems. |
| Comité Científico COP25: Criósfera Chilena y Antártica: Recomendaciones desde la evidencia científica | | González, H.; Bozkurt, D.; Cereceda-Balic, F.; Cordero, R.; Fernandoy, F.; Iriarte, J.; MacDonell, S.; McPhee, J.; Poulin, E.; Rivera, A.; Schaefer, M. | 2019 | Agua y Extremos | | https://www.minciencia.gob.cl/comitecientifico/documentos/mesa-adaptacion/1.Adaptacion-Brechas-Aldunce.pdf | | | | | | | Chile es uno de los países más vulnerables al cambio climático, principalmente, debido a su configuración biogeográfica. Sus efectos ya se están manifestando, principalmente por una prologada y extensa sequía. En este contexto, es urgente la adopción de medidas de mitigación y adaptación para enfrentar los impactos actuales y los adversos escenarios futuros que predicen los modelos climáticos. La criósfera antártica y andina incluye los hielos continentales y marinos permanentes o estacionales, localizados en la península Antártica (PA) y en la región Subantártica (SANT), junto con el macizo Andino en su conjunto. La criósfera alberga una especial biodiversidad que sustenta una serie de subsistemas ecológicos (p. ej., vegas, bofedales, turberas, glaciares, permafrost, lagos subglaciales, tundras marinas, etc.) y servicios ecosistémicos vitales (agua, recreación, regulación climática, biodiversidad, alimento, turismo, etc.), los que están seriamente amenazados por el cambio climático, con negativas consecuencias para el medio ambiente, el clima y la sociedad (reducción del bienestar humano). La criósfera antártica y andina está siendo muy afectada por el alza global de la temperatura (IPCC, 2019). La pérdida de hielo continental en la Antártica se aceleró más de seis veces en las últimas cuatro décadas, mientras que el 87 % de los glaciares andinos monitoreados en territorio nacional exhiben algún grado de retroceso. Hoy, el hielo perdido por la Antártica es promotor de aproximadamente el 10 % del alza global en el nivel de mar; entretanto, el derretimiento de los glaciares andinos, especialmente aquellos en los Campos de Hielo patagónicos, es el responsable de cerca del 3 % del alza global en el nivel de mar |
| Spatial variability of near-surface temperature over the coastal mountains in southern Chile (38°S) | Meteorology and Atmospheric Physics | González, S.; Garreaud, R. | 2019 | Agua y Extremos | 10.1007/s00703-017-0555-4 | http://link.springer.com/10.1007/s00703-017-0555-4 | 89-104 | Vol: 131 Issue: 3 | 0177-7971, 1436-5065 | Thomson Reuters ISI (SCIE) | | English | The spatial distribution of the near-surface air temperature over a coastal mountain range in southern Chile [Nahuelbuta Mountains (NM), 38°S, maximum height 1300-m ASL] is investigated using in situ measurements, satellite-derived land-surface temperature, and simulations during the austral winter of 2011. Based on a few selected but representative cases, we found that under rainy conditions—either at day or night—temperature decreases with height close to the moist adiabatic lapse rate (~6.5 °C/km). Likewise, the temperature tends to follow the dry adiabat (~9.8 °C/km) during daytime under dry- and clear-skies conditions. During clear-skies nights, the temperature also decreases with height over the southeastern side of NM, but it often increases (at about 8 °C/km) over the northwestern side of the mountains. This temperature inversion extends up to about 700-m ASL leading to an average temperature contrast of about 7 °C between the northwestern and southeastern sides of Nahuelbuta by the end of dry nights. These dawns also feature substantial temperature differences (>10 °C) among closely located stations at a same altitude. High-resolution numerical simulations suggest that upstream blocking of the prevailing SE flow, hydrostatic mountain waves, and strong downslope winds is responsible for such distinctive nocturnal temperature distribution. © 2017, The Author(s). |
| A 15,400-year long record of vegetation, fire-regime, and climate changes from the northern Patagonian Andes | Quaternary Science Reviews | Jara, I.; Moreno, P.; Alloway, B.; Newnham, R. | 2019 | Agua y Extremos | 10.1016/j.quascirev.2019.106005 | https://linkinghub.elsevier.com/retrieve/pii/S0277379119305281 | 106005 | Vol: 226 | 0277-3791 | Thomson Reuters ISI (SCIE) | | English | Paleoecological studies from the northern Patagonian Andes (40–44°S) have identified past changes in vegetation, fire regimes and paleoclimate since the last glaciation, including variations in strength and position of the Southern Westerly Winds (SWW). The extent to which records west and east of the Andes provide a congruent paleoclimatic history, however, has not been explored in detail in the literature. Physical and biological contrasts are evident between these regions today and are to be expected in paleoclimate reconstructions. In this context, we present pollen and charcoal records from sediment cores collected in Lago Espejo, a small closed-basin lake located in the core sector of the northern Patagonian Andes that spans uninterrupted the last ∼15,400 years. Following glacier withdrawal, the vegetation surrounding Lago Espejo features scattered Nothofagus woodlands, including relatively thermophilous rainforest trees between ∼15,400 and 14,400 cal yr BP. The disappearance of these trees and an abrupt rise in Nothofagus at ∼14,400 cal yr BP mark the establishment of closed-canopy forests during the Antarctic Cold Reversal, followed by increases in the cold-tolerant hygrophilous conifer Podocarpus nubigena during the Younger Dryas (∼12,700–11,500 cal yr BP). The Holocene vegetation consists of Nothofagus-dominated forests with modest variation in composition and structure until the present, attesting to the resilience of these forest communities to climate change and natural disturbance regimes. Rapid deforestation, anthropogenic fires and the establishment of artificial meadows with exotic herbs introduced by Europeans at ∼150 cal yr BP, triggered a rapid, large-magnitude landscape transformation unprecedented in the last 14,000 years. The timing and structure of vegetation changes revealed by the Lago Espejo record suggest that changes in the SWW were the main driver of vegetation and fire regimes in the Andes of northern Patagonia over the last 15,400 years. Comparison between multiple reconstructions from northern Patagonia reveals overall coherent vegetation and fire regime changes in the western and Andean sectors, and a spatially variable and more divergent behaviour in sites located further east. This spatial patter is akin to the present-day correlation between precipitation and SWW in this region. |
| On the evaluation of adaptation practices: a transdisciplinary exploration of drought measures in Chile | Sustainability Science | Lillo-Ortega, G.; Aldunce, P.; Adler, C.; Vidal, M.; Rojas, M. | 2019 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.1007/s11625-018-0619-5 | http://link.springer.com/10.1007/s11625-018-0619-5 | 1057–1069 | Vol: 14 | 1862-4065 | Thomson Reuters ISI (SCIE) | | English | A severe drought has affected central Chile since 2009. Various adaptation responses have been developed, and a participatory process is required to learn from them. To enable this, a transdisciplinary approach was adopted to achieve two objectives: first, to test an approach for assessing the effectiveness of existing measures to respond to drought, specifically to distil strengths and weaknesses of implementation, and developing recommendations; second, to reflect on results from a pilot project conducted to ascertain its potential for scalability in terms of processes employed. The research was organized per the three types of knowledge needed to address complex problems through transdisciplinarity: systems, target and transformation knowledge. Using the recent drought as a boundary object, we conducted the pilot in two locations in Chile where we carried out literature reviews, interviews and focus group discussions were carried out. We identified adaptation measures at national and local scale, a set of which were evaluated applying the Index for the Usefulness of Adaptation Practices (IUPA). Results indicate that through IUPA, we could systematically account for the perceived effectiveness of applied measures. Strengths such as autonomy in the decision-making process emerged as key factors that could also be applied in other contexts, whereas weaknesses such as lack of integration with other policy domains, programs or projects were identified. To address weaknesses, key recommendations were proposed, which are congruent with context-specific expectations, capacities, experiences and knowledge, given that they were articulated by local actors. Results present empirical evidence on the important utility of transdisciplinary approaches in the evaluation of adaptation measures and can support the development of metrics related to adaptation process at the local scale. |
| Streamflow variations across the Andes (18°–55°S) during the instrumental era | Scientific Reports | Masiokas, M.; Cara, L.; Villalba, R.; Pitte, P.; Luckman, B.; Toum, E.; Christie, D.; Le Quesne, C.; Mauget, S. | 2019 | Agua y Extremos | 10.1038/s41598-019-53981-x | http://www.nature.com/articles/s41598-019-53981-x | 17879 | Vol: 9 Issue: 1 | 2045-2322 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The rivers originating in the southern Andes (18°–55°S) support numerous ecosystems and a large number of human populations and socio-economic activities in the adjacent lowlands of Chile, Argentina and Bolivia. Here we show that ca. 75% of the total variance in the streamflow records from this extensive region can be explained by only eight spatially coherent patterns of variability. Five (three) of these Andean patterns exhibit extreme dry (wet) conditions in recent years, with strong interannual variations in northern Chile; long-term drying trends between 31° and 41°S; a transitional pattern in the central Patagonian Andes; and increasing trends in northwestern Argentina and southern Bolivia, the Fueguian Andes, and the eastern portion of the South Patagonian Icefield. Multivariate regression analyses show that large-scale indices of ENSO variability can predict 20% to 45% of annual runoff variability between 28° and 46°S. The influence of Antarctic and North Pacific indices becomes more relevant south of 43°S and in northwestern Argentina and southern Bolivia, respectively, but their overall skill as predictors of Andean streamflows is weak. The analyses provide relevant new information to improve understanding of the spatial coherence, the main temporal features, and the ocean-atmospheric forcings of surface runoff across the southern Andes. |
| Early arboreal colonization, postglacial resilience of deciduous Nothofagus forests, and the Southern Westerly Wind influence in central-east Andean Patagonia | Quaternary Science Reviews | Moreno, P.; Simi, E.; Villa-Martínez, R.; Vilanova, I. | 2019 | Agua y Extremos | 10.1016/j.quascirev.2019.06.004 | https://linkinghub.elsevier.com/retrieve/pii/S0277379119301222 | 61-74 | Vol: 218 | 0277-3791 | Thomson Reuters ISI (SCIE) | | English | The history and dynamics of deciduous Nothofagus forests along the eastern slopes of the central Patagonian Andes (44°-49°S) remain insufficiently studied and understood, particularly at timescales ranging from centuries to millennia. Available fossil pollen records point to time-transgressive responses of the arboreal vegetation to climatic changes during the Last Glacial Termination (T1) and early Holocene, and spatial heterogeneity since then along north-south, east-west, and elevation transects. The degree to which these results represent biogeographic and climatic trends, varying environmental gradients, or site-specific phenomena has not been assessed in detail. Here we present a fossil pollen and macroscopic charcoal record from Lago Churrasco (45°41′S, 71°49′W), a small closed-basin lake located in the deciduous Nothofagus forest zone of the central-east Andes of Chilean Patagonia. Our results suggest that Nothofagus trees colonized newly deglaciated terrains at ∼16,000 cal yr BP and formed scrublands/woodlands several millennia earlier than reported by previous studies east of the Andes. This suggests expansion and local densification of tree populations sourced from the eastern margin of the Patagonian Ice Sheet during the Last Glacial Maximum, with the additional implication that temperature and precipitation conditions favorable for tree survival and reproduction developed early during T1. We posit that the amount of moisture delivered by the Southern Westerly Winds was not a limiting factor for arboreal expansion during T1 in this sector of the central Patagonian Andes. Closed-canopy Nothofagus forests established at ∼10,000 cal yr BP and have remained essentially invariant despite climate change and natural disturbance regimes. This resilience was challenged and exceeded by human disturbance during the 20th century through the use of fire, leading to deforestation and spread of invasive exotic species in an extraordinarily rapid event. Our record suggests a permanent influence of the Southern Westerly Winds over the last 10,000 years, with relatively modest variations at centennial and millennial timescales. |
| Comité Científico COP25: Transformation from science to decision making | | Moser, S.; Aldunce, P.; Rudnick, A.; Rojas, M.; Muñoz, L. | 2019 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | | https://www.minciencia.gob.cl/comitecientifico/documentos/mesa-adaptacion/4.Adaptation-Transformation-Policy-Brief.pdf | | | | | | | The IPCC2 understands Transformations as systemic changes that enable more ambitious, i.e., significant and rapid, advances in mitigation and adaptation than currently being observed, while also pursuing the Sustainable Development Goals of Agenda 2030. While challenging, deep and difficult transformational change is seen as an opportunity to improve human and natural conditions. Mitigation, adaptation and sustainability should thus be seen as complementary, not competing goals. Transformation means going beyond the familiar in policy- and decision-making, with actors in all sectors focused on shifting the conditions that hold damaging systems in place. |
| Comité Científico COP25: Transformación desde la ciencia a la toma de decisiones | | Moser, S.; Aldunce, P.; Rudnick, A.; Rojas, M.; Muñoz, L. | 2019 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | | https://www.minciencia.gob.cl/comitecientifico/documentos/mesa-adaptacion/3.Adaptacion-Transformacion-Resumen-de-politicas.pdf | | | | | | | El IPCC2 entiende por transformación aquellos cambios sistémicos que permiten avances más ambiciosos en mitigación y adaptación, es decir, significativos y rápidos, más allá de lo observado en la actualidad, y que al mismo tiempo persigan los Objetivos de Desarrollo Sostenible (ODS) de la Agenda 2030. Si bien los cambios transformadores pueden ser desafiantes, profundos y difíciles, también constituyen una oportunidad para mejorar las condiciones de la sociedad y de la naturaleza. La mitigación, la adaptación y la transformación no deben considerarse como enfoques competitivos, sino como complementarios. La transformación significa ir más allá de lo que se ha hecho hasta ahora en la política y toma de decisiones. Para lograrlo, se requieren actores de todos los sectores, enfocados en cambiar las condiciones para mantener y mejorar los sistemas dañados |
| Multidecadal environmental pollution in a mega-industrial area in central Chile registered by tree rings | Science of The Total Environment | Muñoz, A.; Klock-Barría, K.; Sheppard, P.; Aguilera-Betti, I.; Toledo-Guerrero, I.; Christie, D.; Gorena, T.; Gallardo, L.; González-Reyes, Á.; Lara, A.; Lambert, F.; Gayo, E.; Barraza, F.; Chávez, R. | 2019 | Agua y Extremos; Ciudades Resilientes | 10.1016/j.scitotenv.2019.133915 | https://linkinghub.elsevier.com/retrieve/pii/S0048969719338653 | 133915 | Vol: 696 | 0048-9697 | Thomson Reuters ISI (SCIE) | | English | One of the most polluted areas in Chile is the Ventanas Industrial Area (VIA; 32.74°S / 71.48°W), which started in 1958 and today comprises around 16 industries in an area of ca. 4 km2. A lack of consistent long-term instrumental records precludes assessing the history of contamination in the area and also limits the evaluation of mitigation actions taken since the late 1980s. Here, we use dendrochemistry as an environmental proxy to analyze environmental changes over several decades at the VIA. We present chemical measurements of tree rings from planted, exotic Cupressus macrocarpa growing near the VIA with 4-year resolution over a period of 52 years (1960–2011). These data provide unprecedented information on regional anthropogenic pollution and are compared with a tree-ring elemental record of 48 years (1964–2011) from the Isla Negra (INE) control site not exposed to VIA emissions. For the 48 years of overlap between both sites, higher concentrations of Zn, V, Co, Cd, Ag, Fe, Cr, and Al were especially registered after the year 2000 at VIA compared to INE for the periods under study. Concentrations of Pb, Cu, As, Fe, Mo, Cr, and Zn increased through time, particularly over the period 1980–1990. Decontamination plans activated in 1992 appear to have had a positive effect on the amount of some elements, but the chemical concentration in the tree rings suggest continued accumulation of pollutants in the environment. Only after several years of implementation of the mitigation measures have some elements tended to decrease in concentration, especially at the end of the evaluated period. Dendrochemistry is a useful tool to provide a long-term perspective of the dynamics of trace metal pollution and represents a powerful approach to monitor air quality variability to extend the instrumental records back in time. |
| 2018 International Atmospheric Rivers Conference: Multi‐disciplinary studies and high‐impact applications of atmospheric rivers | Atmospheric Science Letters | Ramos, A.; Wilson, A.; DeFlorio, M.; Warner, M.; Barnes, E.; Garreaud, R.; Gorodetskaya, I.; Lavers, D.; Moore, B.; Payne, A.; Smallcomb, C.; Sodemann, H.; Wehner, M.; Ralph, F. | 2019 | Agua y Extremos | 10.1002/asl.935 | https://onlinelibrary.wiley.com/doi/abs/10.1002/asl.935 | art: e935 | Vol: 20 Issue: 9 | 1530-261X | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Atmospheric rivers (ARs) play a vital role in shaping the hydroclimate of many regions globally, and can substantially impact water resource management, emergency response planning, and other socioeconomic entities. The second International Atmospheric Rivers Conference took place at the Scripps Institution of Oceanography, University of California, San Diego, during 25–28 June, 2018, in La Jolla, California, USA. It was sponsored by the Center for Western Weather and Water Extremes (CW3E). A total of 120 people attended the Conference with 94 abstracts submitted and 30 participating students. In addition to the conference, the Student Forecasting Workshop was organised in the same week. During this workshop, students were exposed to AR forecasting tools, and learned examples of how these tools could be used to make decisions for various applications. The main goals of this conference were to bring together experts from across the fields of hydrology, atmospheric, oceanic, and polar sciences, as well as water management, civil engineering, and ecology to advance the state of AR science and to explore the future directions for the field. The conference was organised into traditional oral and poster presentations, along with panel discussions and Breakout Groups. This format allowed enhanced interaction between participants, driving progress within the scientific community and the enhanced communication of societal needs by various stakeholders. Several emerging topics of research were highlighted, including subseasonal‐to‐seasonal (S2S) prediction of ARs and an overview of the AR Reconnaissance campaign. In addition to providing a forum to disseminate and debate new results from scientific talks and posters, the conference was equally effective and useful in linking scientists to users and decision‐makers that require improved knowledge on ARs to manage resources and prepare for hazards.
The third International Atmospheric Rivers Conference will be held in Chile in 2020, and hosted by the University of Chile, Santiago. |
| Holocene glacier fluctuations in Patagonia are modulated by summer insolation intensity and paced by Southern Annular Mode-like variability | Quaternary Science Reviews | Reynhout, S.; Sagredo, E.; Kaplan, M.; Aravena, J.; Martini, M.; Moreno, P.; Rojas, M.; Schwartz, R.; Schaefer, J. | 2019 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.1016/j.quascirev.2019.05.029 | https://linkinghub.elsevier.com/retrieve/pii/S0277379119300745 | 178-187 | Vol: 220 | 0277-3791 | Thomson Reuters ISI (SCIE) | | English | Alpine glaciers are sensitive indicators of changes in climate, and their ubiquity in mountainous regions make them valuable proxies for terrestrial climate reconstructions worldwide. However, the timing and extent of glacier change across the South American mid-latitudes through the Holocene are still poorly constrained relative to their counterparts in the Northern Hemisphere. Here we report a new 10Be surface exposure-based chronology of moraines recording a series of progressively less-extensive glacier advances of Glaciar Torre (Argentina, 49.3°S/73.0°W) since the Last Glacial Maximum, with expansions culminating at 17,600 ± 900, 13,500 ± 500, 9700 ± 400, 6900 ± 200, 6100 ± 300, 4500 ± 200, and 530 ± 60 yr BP. The declining magnitude of Holocene glacier expansions parallels a gradual rise in local summer insolation intensity during the Holocene, while individual advances occurred during inferred negative Southern Annular Mode (SAM)-like states at centennial to millennial timescales. These observations suggest that (i) summer insolation intensity modulated antiphased trends in glacier extent in the polar hemispheres during the Holocene, and that (ii) centennial-scale ‘SAM-like’ temperature and precipitation anomalies paced glacier fluctuations throughout Patagonia. Given the persistence of the inferred ’SAM-like’ anomalies throughout the Holocene, the modern measured trend towards positive SAM index conditions could mark the onset of a fundamental shift in the climate of the Southern Hemisphere midlatitudes that warrants consideration in projections of future climate. |
| Validation of Cryogenic Vacuum Extraction of Pore Water from Volcanic Soils for Isotopic Analysis | Water | Rivera, D.; Gutierrez, K.; Valdivia-Cea, W.; Zambrano-Bigiarini, M.; Godoy-Faúndez, A.; Álvez, A.; Farías, L. | 2019 | Agua y Extremos; Zonas Costeras | 10.3390/w11112214 | https://www.mdpi.com/2073-4441/11/11/2214 | 2214 | Vol: 11 Issue: 11 | 2073-4441 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Andean headwater catchments are key components of the hydrological cycle, given that they capture moisture, store water and release it for Chilean cities, industry, agriculture, and cities in Chile. However, knowledge about within-Andean catchment processes is far from clear. Most soils in the Andes derive from volcanic ash Andosols and Arenosols presenting high organic matter, high-water retention capacity and fine pores; and are very dry during summer. Despite their importance, there is little research on the hillslope hydrology of Andosols. Environmental isotopes such as Deuterium and 18-O are direct tracers for water and useful on analyzing water-soil interactions. This work explores, for the first time, the efficiency of cryogenic vacuum extraction to remove water from two contrasting soil types (Arenosols, Andosols) at five soil water retention energies (from −1500 to −33 kPa). Two experiments were carried out to analyse the impact of extraction time, and initial water content on the amount of extracted water, while a third experiment tested whether the cryogenic vacuum extraction changed the isotopic ratios after extraction. Minimum extraction times to recover over 90% of water initially in the soil samples were 40–50 min and varied with soil texture. Minimum volume for very dry soils were 0.2 mL (loamy sand) and 1 mL (loam). After extraction, the difference between the isotope standard and the isotopic values after extraction was acceptable. Thus, we recommend this procedure for soils derived from volcanic ashes. |
| Comité Científico COP25: Evidencia científica y cambio climático en Chile. Resumen para tomadores de decisiones. | | Rojas, M.; Aldunce, P.; Farías, L.; González, H.; Marquet, P.; Muñoz, J.; Palma-Behnke, R.; Stehr, A.; Vicuña, S. | 2019 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://comitecientifico.minciencia.gob.cl/wp-content/uploads/2021/05/Evidencia-cientifica-y-cambio-climatico-en-Chile-Resumen.pdf | 1-68 | | | | | Spanish | Los resúmenes están basados en los informes y los talleres
del Comité Científico COP25, a los que contribuyeron
investigadores de una red de más de 600 científicos de
todas las disciplinas y regiones de Chile, primordialmente de
universidades y centros de investigación académicos, pero
también de institutos públicos y privados. |
| Strongest MJO on Record Triggers Extreme Atacama Rainfall and Warmth in Antarctica | Geophysical Research Letters | Rondanelli, R.; Hatchett, B.; Rutllant, J.; Bozkurt, D.; Garreaud, R. | 2019 | Agua y Extremos; Zonas Costeras | 10.1029/2018GL081475 | https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081475 | 3482-3491 | Vol: 46 Issue: 6 | 0094-8276 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | Tropical perturbations have been shown theoretically and observationally to excite long range atmospheric responses in the form of Rossby wave teleconnections that result from the equator to pole gradient of planetary vorticity. An extreme teleconnection event occurred during March 2015 in the Southeastern Pacific. As a result, extreme high temperatures were observed in Southwestern South America and the Antarctic Peninsula simultaneously with an extreme rainfall and flood event in the hyperarid Atacama desert.%%%%%%We show that the origin of these seemingly disconnected extreme events can be traced to a Rossby wave response to the strongest Madden‐Julian Oscillation (MJO) on record in the tropical central Pacific. A barotropic wavenumber 3 to 4 perturbation with group velocity between 15 to 30 m/s is consistent with the trajectory and timing followed by the upper level anomalies radiating away from the tropics after the MJO episode. |
| Detecting Nothofagus pumilio Growth Reductions Induced by Past Spring Frosts at the Northern Patagonian Andes | Frontiers in Plant Science | Sangüesa-Barreda, G.; Villalba, R.; Rozas, V.; Christie, D.; Olano, J. | 2019 | Agua y Extremos | 10.3389/fpls.2019.01413 | https://www.frontiersin.org/article/10.3389/fpls.2019.01413/full | 1413 | Vol: 10 | 1664-462X | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access; Green Open Access | English | Extreme climatic events, such as late frosts in spring during leaf flush, have considerable impacts on the radial growth of temperate broadleaf trees. Albeit, all broadleaved species are potentially vulnerable, damage depends on the particularities of the local climate, the species, and its phenology. The impact of late spring frosts has been widely investigated in the Northern Hemisphere, but the potential incidence in Southern Hemisphere tree species is still poorly known. Here, we reconstruct spring frost occurrence at 30 stands of the deciduous tree Nothofagus pumilio in its northern range of distribution in the Patagonian Andes. We identified tree ring-width reductions at stand level not associated with regional or local drought events, matching unusual minimum spring temperatures during leaf unfolding. Several spring frosts were identified along the northern distribution of N. pumilio, being more frequent in the more continental Argentinean forests. Spring frost in 1980 had the largest spatial extent. The spring frosts in 1980 and 1992 also induced damages in regional orchards. Spring frost damage was associated with (i) a period of unusually warm temperatures at the beginning of leaf unfolding, followed by (ii) freezing temperatures. This study helps expand our understanding of the climatic constraints that could determine the future growth and dynamics of Andean deciduous forests and the potential use of tree-rings as archives of extreme events of spring frosts in northern Patagonia. |
| Salmon farming vulnerability to climate change in southern Chile: understanding the biophysical, socioeconomic and governance links | Reviews in Aquaculture | Soto, D.; León‐Muñoz, J.; Dresdner, J.; Luengo, C.; Tapia, F.; Garreaud, R. | 2019 | Agua y Extremos | 10.1111/raq.12336 | https://onlinelibrary.wiley.com/doi/abs/10.1111/raq.12336 | 354-374 | Vol: 11 Issue: 2 | 1753-5123, 1753-5131 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | There has been a growing interest in studying the labile C pool in order to promote the sequestration and stabilization of soil organic carbon (SOC). Although labile SOC fractions have emerged as standardized indicators because of their potential to detect early SOC trends over time, the relationships between microbial attributes and labile SOC remains poorly understood. In this study, we explored the influence of labile SOC fractions on the topsoil bacteria-archaea community across 28 sites with different land use, climate aridity, and soil types across a wide range of SOC content (0.6–12%) in central Chile. We applied Illumina sequencing to the 16S rRNA to examine shifts in the diversity and composition of these soil microbial communities. Additionally, labile SOC fractions such as the permanganate oxidizable carbon (POXC) and light fraction organic matter (LFOM), along with the soil physicochemical properties were analyzed. The results demonstrated that among all of the environmental factors tested, the pH, POXC/SOC ratio and LFOM were key drivers of microbial community structure (β-diversity). The α-diversity metrics exhibited a decreasing trend when aridity increased, and community structure was found to vary, with high POXC/SOC in sites associated with drier conditions. In addition, POXC/SOC ratios and LFOM were clearly related to shifts in the relative abundances of specific taxonomic groups at genera level. When there was high POXC/SOC and low LFOM content, members of Bacteroidetes (Adhaeribacter, Flavisolibacter, and Niastella), Proteobacteria (Skermanella, Ramlibacter, and Sphingomonas), and Archaea (Thaumarchaeota) were found to be the most dominant groups; however, the microbial taxa responded differently to both labile C fraction types. These results have implications for understanding how labile C content can potentially be used to predict shifts in the microbial community, thus facilitating the development of predictive ecosystem models, as well as early warning indicators for soil degradation. |
| Comité Científico COP25: Recursos hídricos en Chile: Impactos y adaptación al cambio climático. Informe de la mesa de Agua. | | Stehr, A.; Álvarez, C.; Álvarez, P.; Arumí, J.; Baeza, C.; Barra, R.; Berroeta, C.; Castillo, Y.; Chiang, G.; Cotoras, D.; Crespo, S.; Delgado, V.; Donoso, G.; Dussaillant, A.; Ferrando, F.; Figueroa, R.; Frêne, C.; Fuster, R.; Godoy, A.; Gómez, T.; Holzapfel, E.; Huneeus, C.; Jara, M.; Little, C.; ... | 2019 | Agua y Extremos; Cambio de Uso de Suelo; Zonas Costeras | | https://www.minciencia.gob.cl/comitecientifico/documentos/mesa-agua/19.Agua-Recursos-Hidricos-Stehr.pdf | | | | | | | La comparación entre el período 1985-2015 y el período 2030-2060 indica una disminución generalizada de las precipitaciones en comparación con la media histórica, pues se proyectan disminuciones promedio de entre 5% y 15% para la zona comprendida entre las cuencas de los ríos Elqui (región de Coquimbo) y el Baker (región de Aysén). Estas proyecciones se acentuarían hacia la zona sur del país, sobre todo entre la cuenca del río Biobío y el límite sur de la región de Los Lagos (Rojas, 2012). De acuerdo con trabajos como Boisier et al. (2016), se han detectado tendencias climáticas recientes en precipitación que siguen la misma dirección proyectada hacia el futuro y que han sido además atribuidas a una manifestación temprana del cambio climático |
| Tras la huella del Cambio Climático | | Troncoso, M.; Rudloff, V. | 2019 | Agua y Extremos; Cambio de Uso de Suelo | | https://www.cr2.cl/wp-content/uploads/2019/10/Tras-la-Huella-del-Cambio-Clima%CC%81tico.pdf | 59 | | | | | Spanish | El cambio climático es una realidad y Chile no está exento de su amenaza. En la última década se ha observado un aumento generalizado de las temperaturas a nivel global, además de otros eventos y alteraciones climáticas en distintas latitudes del planeta, las que han repercutido desfavorablemente en la población. Esto, sumado a la acelerada extinción de especies en el último siglo, nos muestra lo vulnerable que es la vida frente al cambio climático. Nuestro país también se ha visto afectado con las recientes olas de calor y un prolongado défcit de precipitaciones en gran parte de su territorio, lo cual corresponde a la antesala de las proyecciones climáticas para este fn de siglo. Entonces, ¿cómo será la vida en el futuro cercano? El cambio climático que estamos presenciando ha sido producto de la actividad humana, y afecta tanto a las personas y todas sus actividades, como a los ecosistemas que habitan el planeta. Es entonces fundamental hacernos cargo de este problema como sociedad, y para ello debemos entenderlo, estudiarlo y analizarlo desde distintos ángulos, como es desde las ciencias sociales y ciencias naturales. La presente guía de apoyo educacional busca abordar el cambio climático desde este último punto: las ciencias naturales. Presentación; ¿Por qué hacer esta guía de actividades? La comunidad científca ha sido clave en evidenciar el cambio climático, mostrando los motivos y sus posibles consecuencias. Pero esto no basta, ya que toda la sociedad debe ser partícipe a la hora de actuar en su contra. Luego, las personas deben entender la ciencia en torno al cambio climático, y esto comienza desde lo básico: el método científco. Esta guía es, pues, un viaje hacia la indagación científca dentro del marco del medio ambiente, y es importante que profesores y estudiantes trabajen juntos en este nuevo camino. ¿Por qué Chile es vulnerable al cambio climático? ¿Qué estamos haciendo y qué haremos en el futuro? Son preguntas que se están haciendo cada vez más frecuentes tanto en jóvenes como adultos. Es por tanto ahora el momento de que el aula de clases se vuelva un espacio de conversación sobre el cambio climático, y no solo como un tema de carácter global, sino también dentro la experiencia del entorno próximo. Solo mediante la observación de nuestro contexto, el medio ambiente y nuestra historia, es que como sociedad podremos hacer frente al cambio climático. |
| Extreme Daily Rainfall in Central-Southern Chile and Its Relationship with Low-Level Horizontal Water Vapor Fluxes | Journal of Hydrometeorology | Valenzuela, R.; Garreaud, R. | 2019 | Agua y Extremos | 10.1175/JHM-D-19-0036.1 | http://journals.ametsoc.org/doi/10.1175/JHM-D-19-0036.1 | 1829-1850 | Vol: 20 Issue: 9 | 1525-755X | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Extreme rainfall events are thought to be one of the major threats of climate change given an increase of water vapor available in the atmosphere. However, before projecting future changes in extreme rainfall events, it is mandatory to know current patterns. In this study we explore extreme daily rainfall events along central-southern Chile with emphasis in their spatial distribution and concurrent synoptic-scale circulation. Surface rain gauges and reanalysis products from the Climate Forecast System Reanalysis are employed to unravel the dependency between extreme rainfall and horizontal water vapor fluxes. Results indicate that extreme rainfall events can occur everywhere, from the subtropical to extratropical latitudes, but their frequency increases where terrain has higher altitude, especially over the Andes Mountains. The majority of these events concentrate in austral winter, last a single day, and encompass a north–south band of about 200 km in length. Composited synoptic analyses identified extreme rainfall cases dominated by northwesterly (NW) and westerly (W) moisture fluxes. Some features of the NW group include a 300-hPa trough projecting from the extratropics to subtropics, a surface-level depression, and cyclonic winds at 850 hPa along the coast associated with integrated water vapor (IWV) > 30 mm. Conversely, features in the W group include both a very weak 300-hPa trough and surface depression, as well as coastal westerly winds associated with IWV > 30 mm. About half of extreme daily rainfall is associated with an atmospheric river. Extreme rainfall observed in W (NW) cases has a strong orographic (synoptic) forcing. In addition, W cases are, on average, warmer than NW cases, leading to an amplified hydrological response. |
| Comité Científico COP25: Lineamientos para el desarrollo de planes de adaptación: Aplicación de recursos hídricos. Informe de las mesas Adaptación y Agua | | Vicuña, S.; Aldunce, P.; Stehr, A.; Cid, F.; Rivera, A.; Alencar, K.; Álvarez, C.; Barton, J.; Berroeta, C.; Boisier, J.; Bustos, E.; Bustos, S.; Correa, T.; Cortés, S.; Cubillos, L.; De la Barrera, F.; Donoso, F.; Farías, L.; Farías, D.; Fuster, R.; Gese, P.; Godoy, A.; Guerra, L.; Guida, C.; Ibarr... | 2019 | Agua y Extremos; Zonas Costeras | | https://cdn.digital.gob.cl/filer_public/f3/56/f3566a93-a46c-49cf-a73d-86d4a807a5b5/2adaptacion-lineamientosrrhh-vicuna.pdf | | | | | | | La planificación y sus instrumentos de aplicación, como los planes de adaptación, son herramientas fundamentales para abordar los desafíos de la adaptación a distintas escalas espaciales y sectoriales. El uso real de estas herramientas aún es limitado. Su aplicación es dispar, especialmente en el contexto de la región de América Latina. Pocos países han iniciado sus procesos de desarrollo de este tipo de herramientas, y donde se ha hecho, como en Chile, existen vacíos y brechas importantes para desarrollar su potencial. A través de un proceso participativo a lo largo del año basado en talleres con la comunidad científica, se generó una propuesta de lineamientos para el diseño, implementación y seguimiento de planes de adaptación, la que además fue implementada de manera práctica en un ejercicio hipotético de desarrollo de un Plan de Adaptación al Cambio Climático (PACC) para los Recursos Hídricos. Un lineamiento relevante tiene relación con los antecedentes y el proceso de diseño del plan. El explicitar el proceso de diseño utilizado es fundamental para otorgar transparencia y, por lo tanto, validez al plan. En el trabajo de diseño resulta crítico contar con procesos participativos que permitan identificar las principales vulnerabilidades, desafíos y objetivos hacia el futuro. En el contexto de los recursos hídricos esta necesidad es más patente, por lo que se requiere un proceso de participación lo más amplio posible, pero teniendo en cuenta que no es factible —ni deseable— que se incluyan en el desarrollo del plan medidas de adaptación muy específicas en virtud de las necesidades en cada territorio. Estas medidas se deben desarrollar, por ejemplo, en el contexto de planes de acción a una escala regional. Se propone que este proceso se desarrolle al alero de las discusiones que se van a generar respecto de los lineamientos generales de la gestión de recursos hídricos en el país, y en paralelo de las gestiones que actualmente se tienen que desarrollar para resolver los desafíos de la actual megasequía |
| The last glacial termination in the Coyhaique sector of central Patagonia | Quaternary Science Reviews | Vilanova, I.; Moreno, P.; Miranda, C.; Villa-Martínez, R. | 2019 | Agua y Extremos | 10.1016/j.quascirev.2019.105976 | https://linkinghub.elsevier.com/retrieve/pii/S0277379119306572 | 105976 | Vol: 224 | 0277-3791 | Thomson Reuters ISI (SCIE) | | English | Southern South America is the only continental landmass that intersects the core of the Southern Westerly Winds (SWW), and thus is important for studying their role as a driver/conduit for the initiation/propagation of climate signals since the last glaciation. Their interaction with the Southern Ocean (SO) affects global climate through its influence on high-latitude upwelling and biological productivity, deep-water convection sites and, consequently, ventilation of CO2 from the deep ocean. Variations in the SWW-SO coupled system have been postulated as fundamental drivers of climate change during glacial terminations and the current interglacial. Hence, deciphering the evolution of the SWW from sensitive locations in the southern middle latitudes is essential for understanding important climatic transitions during and since the Last Glacial Termination (T1). Terrestrial records from the central Patagonian Andes (CPA) (44°-49°S), however, show heterogeneities in the timing, rates, and direction of climate change during T1, impeding detailed assessment of its drivers at regional, hemispheric, and global scales. Here we present new data on glacier, vegetation, and fire-regime changes in the Coyhaique sector (45°34′S) of CPA to improve our understanding on the timing and structure of the T1, including the behavior of the SWW. Our results indicate glacial recession from the youngest Last Glacial Maximum moraines just before ∼17.9 ka and development of an ice-dammed proglacial lake during the early stages of T1. Drainage of the ice-dammed lake, triggered by renewed glacial recession, was near-synchronous with the onset of a gradual multi-millennial trend toward arboreal dominance that started at ∼16 ka east and west of the Andes at that latitude. We detect increased influence of the SWW at ∼45°S starting at ∼16.6 ka, relative to the first millennium of T1, that led to positive anomalies in precipitation between ∼16–14.4 and ∼12.8–11.5 ka, followed by negative anomalies between ∼11.5–9 ka. The synchronous spread of arboreal vegetation east and west of the CPA divide during T1, despite the trans-Andean precipitation contrasts, suggests an upward shift in the temperature-controlled Andean tree line, underscoring the role of deglacial warming as the critical driver for afforestation at regional scale. |
| The CAMELS-CL dataset - links to files. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.894885 | PANGAEA - Data Publisher for Earth & Environmental Science | Alvarez, C.; Mendoza, P.; Boisier, J.; Addor, N.; Galleguillos, M.; Zambrano-Bigiarini, M.; Lara, A.; Puelma, C.; Cortes, G.; Garreaud, R.; McPhee, J.; Ayala, A. | 2018 | Agua y Extremos; Cambio de Uso de Suelo | 10.1594/PANGAEA.894885 | https://doi.org/10.1594/PANGAEA.894885 | | | | | | | |
| The CAMELS-CL dataset: catchment attributes and meteorology for large sample studies – Chile dataset | Hydrology and Earth System Sciences | Alvarez-Garreton, C.; Mendoza, P.; Boisier, J.; Addor, N.; Galleguillos, M.; Zambrano-Bigiarini, M.; Lara, A.; Puelma, C.; Cortes, G.; Garreaud, R.; McPhee, J.; Ayala, A. | 2018 | Agua y Extremos; Cambio de Uso de Suelo | 10.5194/hess-22-5817-2018 | https://www.hydrol-earth-syst-sci.net/22/5817/2018/ | 5817-5846 | Vol: 22 Issue: 11 | 1607-7938 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | We introduce the first catchment dataset for large sample studies in Chile. This dataset includes 516 catchments; it covers particularly wide latitude (17.8 to 55.0°S) and elevation (0 to 6993ma.s.l.) ranges, and it relies on multiple data sources (including ground data, remote-sensed products and reanalyses) to characterise the hydroclimatic conditions and landscape of a region where in situ measurements are scarce. For each catchment, the dataset provides boundaries, daily streamflow records and basin-averaged daily time series of precipitation (from one national and three global datasets), maximum, minimum and mean temperatures, potential evapotranspiration (PET; from two datasets), and snow water equivalent. We calculated hydro-climatological indices using these time series, and leveraged diverse data sources to extract topographic, geological and land cover features. Relying on publicly available reservoirs and water rights data for the country, we estimated the degree of anthropic intervention within the catchments. To facilitate the use of this dataset and promote common standards in large sample studies, we computed most catchment attributes introduced by Addor et al. (2017) in their Catchment Attributes and MEteorology for Large-sample Studies (CAMELS) dataset, and added several others.
We used the dataset presented here (named CAMELS-CL) to characterise regional variations in hydroclimatic conditions over Chile and to explore how basin behaviour is influenced by catchment attributes and water extractions. Further, CAMELS-CL enabled us to analyse biases and uncertainties in basin-wide precipitation and PET. The characterisation of catchment water balances revealed large discrepancies between precipitation products in arid regions and a systematic precipitation underestimation in headwater mountain catchments (high elevations and steep slopes) over humid regions. We evaluated PET products based on ground data and found a fairly good performance of both products in humid regions (r > 0.91) and lower correlation (r < 0.76) in hyper-arid regions. Further, the satellite-based PET showed a consistent overestimation of observation-based PET. Finally, we explored local anomalies in catchment response by analysing the relationship between hydrological signatures and an attribute characterising the level of anthropic interventions. We showed that larger anthropic interventions are correlated with lower than normal annual flows, runoff ratios, elasticity of runoff with respect to precipitation, and flashiness of runoff, especially in arid catchments.
CAMELS-CL provides unprecedented information on catchments in a region largely underrepresented in large sample studies. This effort is part of an international initiative to create multi-national large sample datasets freely available for the community. CAMELS-CL can be visualised from http://camels.cr2.cl and downloaded from https://doi.pangaea.de/10.1594/PANGAEA.894885. |
| Temporal and spatial evaluation of satellite rainfall estimates over different regions in Latin-America | Atmospheric Research | Baez-Villanueva, O.; Zambrano-Bigiarini, M.; Ribbe, L.; Nauditt, A.; Giraldo-Osorio, J.; Thinh, N. | 2018 | Agua y Extremos | 10.1016/j.atmosres.2018.05.011 | https://linkinghub.elsevier.com/retrieve/pii/S0169809517313029 | 34-50 | Vol: 213 | 01698095 | Thomson Reuters ISI (SCIE) | | English | In developing countries, an accurate representation of the spatio-temporal variability of rainfall is currently severely limited, therefore, satellite-based rainfall estimates (SREs) are promising alternatives. In this work, six state-of-the-art SREs (TRMM 3B42v7, TRMM 3B42RT, CHIRPSv2, CMORPHv1, PERSIANN-CDR, and MSWEPv2) are evaluated over three different basins in Latin-America, using a point-to-pixel comparison at daily, monthly, and seasonal timescales. Three continuous (root mean squared error, modified Kling-Gupta efficiency, and percent bias) and three categorical (probability of detection, false alarm ratio, and frequency bias) indices are used to evaluate the performance of the different SREs, and to assess if the upscaling procedure used, in CHIRPSv2 and MSWEPv2, to enable a consistent point-to-pixel comparison affects the evaluation of the SREs performance at different time scales. Our results show that for Paraiba do Sul in Brazil, MSWEPv2 presented the best performance at daily and monthly time scales, while CHIRPSv2 performed the best at these timescales over the Magdalena River Basin in Colombia. In the Imperial River Basin in Chile, MSWEPv2 and CHIRPSv2 performed the best at daily and monthly time scales, respectively. When the basins were evaluated at seasonal scale, CMORPHv1 performed the best for DJF and SON, TRMM 3B42v7 for MAM, and PERSIANN-CDR for JJA over Imperial Basin. MSWEPv2 performed the best over Paraiba do Sul Basin for all seasons and CHIRPSv2 showed the best performance over Magdalena Basin. The Modified Kling-Gupta efficiency (KGE′) proved to be a useful evaluation index because it decomposes the performance of the SREs into linear correlation, bias, and variability parameters, while the Root Mean Squared Error (RMSE) is not recommended for evaluating SREs performance because it gives more weight to high rainfall events and its results are not comparable between areas with different precipitation regimes. On the other hand, CHIRPSv2 and MSWEPv2 presented different performance, for some study areas and time scales, when evaluated with their original spatial resolution (0.05° and 0.1, respectively) with respect to the evaluation resulting after applying the spatial upscaling (to a unified 0.25), showing that the upscaling procedure might impact the SRE performance. We finally conclude that a site-specific validation is needed before using any SRE, and we recommend to evaluate the SRE performance before and after applying any upscaling procedure in order to select the SRE that best represents the spatio-temporal precipitation patterns of a site. |
| The first 300-year streamflow reconstruction of a high-elevation river in Chile using tree rings: HIGH-ELEVATION CHILEAN RIVER STREAMFLOW RECONSTRUCTION | International Journal of Climatology | Barria, P.; Peel, M.; Walsh, K.; Muñoz, A. | 2018 | Agua y Extremos | 10.1002/joc.5186 | http://doi.wiley.com/10.1002/joc.5186 | 436-451 | Vol: 38 Issue: 1 | 0899-8418 | Thomson Reuters ISI (SCIE) | | English | In central Chile, increasing demand for water and decreasing runoff volumes due to drier conditions have placed catchments in this zone under water stress. However, scarcity of observed data records increases the difficulty of planning future water supply. Instrumental records suggest a reduction in streamflow over the last 56 years. However, this change is not statistically significant and the lack of meteorological stations with long records in this mountainous region hampers a deeper analysis, motivating the use of tree rings to analyse whether these changes are part of a long-term trend. This work represents the first high-elevation runoff reconstruction in Chile using 300 years of tree ring chronologies of Araucaria araucana and Astroceudrus chilensis. The upper part of Biobío river melting season runoff (October–March) and pluvial season runoff (April–September) was reconstructed and analysed to investigate the influence of large-scale climatic drivers on runoff generation, current drought trends and to improve the understanding of climate variability in this region. We obtained positive correlations between the 20-year moving average of reconstructed pluvial season runoff and reconstructed Pacific Decadal Oscillation (PDO), which is indicative of multi-decadal variability. We also found a negative correlation between the 11-year moving average of reconstructed melting season runoff and the PDO and positive correlations with the Southern Annular Mode (SAM). Important differences in the runoff variability of the upper and the lower part of the catchment were identified which are in part led by the influence of the large-scale climatic features that drive runoff generation in both regions. We found that the changes observed in the instrumental records are part of multi-decadal cycles led by the PDO and SAM for pluvial season runoff and melting season runoff, respectively. |
| Alternative approaches for estimating missing climate data: application to monthly precipitation records in South-Central Chile | Forest Ecosystems | Barrios, A.; Trincado, G.; Garreaud, R. | 2018 | Agua y Extremos | 10.1186/s40663-018-0147-x | https://forestecosyst.springeropen.com/articles/10.1186/s40663-018-0147-x | art: 28 | Vol: 5 Issue: 1 | 2197-5620 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Background
Over the last decades interest has grown on how climate change impacts forest resources. However, one of the main constraints is that meteorological stations are riddled with missing climatic data. This study compared five approaches for estimating monthly precipitation records: inverse distance weighting (IDW), a modification of IDW that includes elevation differences between target and neighboring stations (IDWm), correlation coefficient weighting (CCW), multiple linear regression (MLR) and artificial neural networks (ANN).
Methods
A complete series of monthly precipitation records (1995–2012) from twenty meteorological stations located in central Chile were used. Two target stations were selected and their neighboring stations, located within a radius of 25 km (3 stations) and 50 km (9 stations), were identified. Cross-validation was used for evaluating the accuracy of the estimation approaches. The performance and predictive capability of the approaches were evaluated using the ratio of the root mean square error to the standard deviation of measured data (RSR), the percent bias (PBIAS), and the Nash-Sutcliffe efficiency (NSE). For testing the main and interactive effects of the radius of influence and estimation approaches, a two-level factorial design considering the target station as the blocking factor was used.
Results
ANN and MLR showed the best statistics for all the stations and radius of influence. However, these approaches were not significantly different with IDWm. Inclusion of elevation differences into IDW significantly improved IDWm estimates. In terms of precision, similar estimates were obtained when applying ANN, MLR or IDWm, and the radius of influence had a significant influence on their estimates, we conclude that estimates based on nine neighboring stations located within a radius of 50 km are needed for completing missing monthly precipitation data in regions with complex topography.
Conclusions
It is concluded that approaches based on ANN, MLR and IDWm had the best performance in two sectors located in south-central Chile with a complex topography. A radius of influence of 50 km (9 neighboring stations) is recommended for completing monthly precipitation data. |
| Anthropogenic drying in central-southern Chile evidenced by long-term observations and climate model simulations | Elementa: Science of the Anthropocene | Boisier, J.; Alvarez-Garretón, C.; Cordero, R.; Damiani, A.; Gallardo, L.; Garreaud, R.; Lambert, F.; Ramallo, C.; Rojas, M.; Rondanelli, R. | 2018 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | 10.1525/elementa.328 | https://www.elementascience.org/article/10.1525/elementa.328/ | 74 | Vol: 6 Issue: 1 | 2325-1026 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The socio-ecological sensitivity to water deficits makes Chile highly vulnerable to global change. New evidence of a multi-decadal drying trend and the impacts of a persistent drought that since 2010 has affected several regions of the country, reinforce the need for clear diagnoses of the hydro-climate changes in Chile. Based on the analysis of long-term records (50+ years) of precipitation and streamflow, we confirm a tendency toward a dryer condition in central-southern Chile (30–48°S). We describe the geographical and seasonal character of this trend, as well as the associated large-scale circulation pat- terns. When a large ensemble of climate model simulations is contrasted to observations, anthropogenic forcing appears as the leading factor of precipitation change. In addition to a drying trend driven by greenhouse gas forcing in all seasons, our results indicate that the Antarctic stratospheric ozone deple- tion has played a major role in the summer rainfall decline. Although average model results agree well with the drying trend’s seasonal character, the observed change magnitude is two to three times larger than that simulated, indicating a potential underestimation of future projections for this region. Under present-day carbon emission rates, the drying pathway in Chile will likely prevail during the next decades, although the summer signal should weaken as a result of the gradual ozone layer recovery. The trends and scenarios shown here pose substantial stress on Chilean society and its institutions, and call for urgent action regarding adaptation measures. |
| Projected hydroclimate changes over Andean basins in central Chile from downscaled CMIP5 models under the low and high emission scenarios | Climatic Change | Bozkurt, D.; Rojas, M.; Boisier, J.; Valdivieso, J. | 2018 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.1007/s10584-018-2246-7 | http://link.springer.com/10.1007/s10584-018-2246-7 | 131-147 | Vol: 150 Issue: 3-4 | 0165-0009 | Thomson Reuters ISI (SCIE) | | English | This study examines the projections of hydroclimatic regimes and extremes over Andean basins in central Chile (approximate to 30-40 degrees S) under a low and high emission scenarios (RCP2.6 and RCP8.5, respectively). A gridded daily precipitation and temperature dataset based on observations is used to drive and validate the VIC macro-scale hydrological model in the region of interest. Historical and future simulations from 19 climate models participating in CMIP5 have been adjusted with the observational dataset and then used to make hydrological projections. By the end of the century, there is a large difference between the scenarios, with projected warming of approximate to + 1.2 degrees C (RCP2.6), approximate to +3.5 degrees C (RCP8.5) and drying of approximate to - 3% (RCP2.6), approximate to - 30% (RCP8.5). Following the strong drying and warming projected in this region under the RCP8.5 scenario, the VIC model simulates decreases in annual runoff of about 40% by the end of the century. Such strong regional effect of climate change may have large implications for the water resources of this region. Even under the low emission scenario, the Andes snowpack is projected to decrease by 35-45% by mid-century. In more snowmelt-dominated areas, the projected hydrological changes under RCP8.5 go together with more loss in the snowpack (75-85%) and a temporal shift in the center timing of runoff to earlier dates (up to 5 weeks by the end of the century). The severity and frequency of extreme hydroclimatic events are also projected to increase in the future. The occurrence of extended droughts, such as the recently experienced mega-drought (2010-2015), increases from one to up to five events per 100 years under RCP8.5. Concurrently, probability density function of 3-day peak runoff indicates an increase in the frequency of flood events. The estimated return periods of 3-day peak runoff events depict more drastic changes and increase in the flood risk as higher recurrence intervals are considered by mid-century under RCP2.6 and RCP8.5, and by the end of the century under RCP8.5. |
| Foehn Event Triggered by an Atmospheric River Underlies Record-Setting Temperature Along Continental Antarctica | Journal of Geophysical Research: Atmospheres | Bozkurt, D.; Rondanelli, R.; Marín, J.; Garreaud, R. | 2018 | Agua y Extremos; Zonas Costeras | 10.1002/2017JD027796 | http://doi.wiley.com/10.1002/2017JD027796 | 3871-3892 | Vol: 123 Issue: 8 | 2169-897X | Thomson Reuters ISI (SCIE) | | English | A record‐setting temperature of 17.5°C occurred on 24 March 2015 at the Esperanza station located near the northern tip of the Antarctic Peninsula (AP). We studied the event using surface station data, satellite imagery, reanalysis data, and numerical simulations. The Moderate Resolution Imaging Spectroradiometer Antarctic Ice Shelf Image Archive provides clear evidence for disintegration and advection of sea ice, as well as the formation of melt ponds on the ice sheet surface at the base of the AP mountain range. A deep low‐pressure center over the Amundsen‐Bellingshausen Sea and a blocking ridge over the southeast Pacific provided favorable conditions for the development of an atmospheric river with a northwest‐southeast orientation, directing warm and moist air toward the AP, and triggering a widespread foehn episode. A control simulation using a regional climate model shows the existence of local topographically induced warming along the northern tip of the AP (∼60% of the full temperature signal) and the central part of the eastern AP (>90% of the full temperature signal) with respect to a simulation without topography. These modeling results suggest that more than half of the warming experienced at Esperanza can be attributed to the foehn effect (a local process), rather than to the large‐scale advection of warm air from the midlatitudes. Nevertheless, the local foehn effect also has a large‐scale advection component, since the atmospheric river provides water vapor for orographic precipitation enhancement and latent heat release, which makes it difficult to completely disentangle the role of local versus large‐scale processes in explaining the extreme event. |
| Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE | Nature Communications | Büntgen, U.; Wacker, L.; Galván, J.; Arnold, S.; Arseneault, D.; Baillie, M.; Beer, J.; Bernabei, M.; Bleicher, N.; Boswijk, G.; Bräuning, A.; Carrer, M.; Ljungqvist, F.; Cherubini, P.; Christl, M.; Christie, D.; Clark, P.; Cook, E.; D’Arrigo, R.; Davi, N.; Eggertsson, Ó.; Esper, J.; Fowler, A.; Ged... | 2018 | Agua y Extremos; Cambio de Uso de Suelo | 10.1038/s41467-018-06036-0 | http://www.nature.com/articles/s41467-018-06036-0 | art: 3605 | Vol: 9 Issue: 1 | 2041-1723 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the 14C content in 484 individual tree rings formed in the periods 770–780 and 990–1000 CE. Distinct 14C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved 14C measurements are needed. |
| Dendrohydrology and water resources management in south-central Chile: lessons from the Río Imperial streamflow reconstruction | Hydrology and Earth System Sciences | Fernández, A.; Muñoz, A.; González-Reyes, Á.; Aguilera-Betti, I.; Toledo, I.; Puchi, P.; Sauchyn, D.; Crespo, S.; Frene, C.; Mundo, I.; González, M.; Vignola, R. | 2018 | Agua y Extremos | 10.5194/hess-22-2921-2018 | https://www.hydrol-earth-syst-sci.net/22/2921/2018/ | 2921-2935 | Vol: 22 Issue: 5 | 1607-7938 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Streamflow in south-central Chile (SCC, ∼ 37–42° S) is vital for agriculture, forestry production, hydroelectricity, and human consumption. Recent drought episodes have generated hydrological deficits with damaging effects on these activities. This region is projected to undergo major reductions in water availability, concomitant with projected increases in water demand. However, the lack of long-term records hampers the development of accurate estimations of natural variability and trends. In order to provide more information on long-term streamflow variability and trends in SCC, here we report findings of an analysis of instrumental records and a tree-ring reconstruction of the summer streamflow of the Río Imperial ( ∼ 37° 40′ S–38° 50′ S). This is the first reconstruction in Chile targeted at this season. Results from the instrumental streamflow record ( ∼ 1940 onwards) indicated that the hydrological regime is fundamentally pluvial with a small snowmelt contribution during spring, and evidenced a decreasing trend, both for the summer and the full annual record. The reconstruction showed that streamflow below the average characterized the post-1980 period, with more frequent, but not more intense, drought episodes. We additionally found that the recent positive phase of the Southern Annular Mode has significantly influenced streamflow. These findings agree with previous studies, suggesting a robust regional signal and a shift to a new hydrological scenario. In this paper, we also discuss implications of these results for water managers and stakeholders; we provide rationale and examples that support the need for the incorporation of tree-ring reconstructions into water resources management. |
| A plausible atmospheric trigger for the 2017 coastal El Niño: THE 2017 COASTAL EL NIÑO | International Journal of Climatology | Garreaud, R. | 2018 | Agua y Extremos | 10.1002/joc.5426 | http://doi.wiley.com/10.1002/joc.5426 | e1296-e1302 | Vol: 38 | 0899-8418 | Thomson Reuters ISI (SCIE) | | English | The far eastern tropical Pacific experienced a rapid, marked warming in early 2017, causing torrential rains along the west coast of South America with a significant societal toll in Peru and Ecuador. This strong coastal El Niño was largely unpredicted, even a few weeks before its onset, and it developed differently from either central or eastern events. Here we provide an overview of the event, its impacts and concomitant atmospheric circulation. It is proposed that a remotely forced, sustained weakening of the free tropospheric westerly flow impinging the subtropical Andes leads to a relaxation of the southeasterly (SE) trades off the coast, which in turn may have warmed the eastern Pacific throughout the weakening of upwelling in a near-coastal band and the lessening of the evaporative cooling farther offshore. |
| Record-breaking climate anomalies lead to severe drought and environmental disruption in western Patagonia in 2016 | Climate Research | Garreaud, R. | 2018 | Agua y Extremos | 10.3354/cr01505 | http://www.int-res.com/abstracts/cr/v74/n3/p217-229/ | 217-229 | Vol: 74 Issue: 3 | 0936-577X | Thomson Reuters ISI (SCIE) | | English | Traditionally a temperate and hyper-humid region, western Patagonia experienced its most severe drought during the summer and fall of 2016. Along with precipitation deficits larger than 50% there was a similar reduction in river discharge into coastal waters, a decline in vegetation productivity, excessive solar radiation at the surface, and frequent upwelling-favorable wind events offshore. The combination of these regional-scale anomalies seems to have set the stage for environmental disturbances that, although not new in western Patagonia, occurred with unprecedented magnitude, including severe urban air pollution episodes, large forest fires, and the worst ever recorded harmful algae bloom (HAB). The local climate anomalies were in turn related to the concomitant strong El Niño (through atmospheric teleconnections) and, to a lesser extent, anthropogenic climate change mediated by the positive polarity of the Southern Annular Mode (SAM) and internal variability, as both modes weakened the westerlies. Dryer than present conditions are consistently projected for northern Patagonia during the 21st century as a consequence of anthropogenic increases in radiative forcing; superposition of El Niño events in this altered climate may result in a higher frequency of extreme droughts and environmental disruptions like those observed in 2016. |
| Tres niños sorprendentes | Boletín Técnico Instituto de Geofísica del Perú (IGP) | Garreaud, R. | 2018 | Agua y Extremos | | http://intranet.igp.gob.pe/sysppr/results/result_71/Boletin_Tecnico_PPR_El_Nino_IGP_201801.pdf | 5-9 | Vol: 5 Issue: 1 | | | | | Aunque el fenómeno de El Niño–Oscilación del
Sur (ENOS) se desarrolla en el Pacífico tropical, las
alteraciones climáticas durante sus fases extremas (El
Niño y La Niña) se extienden a gran parte del planeta
(Diaz & Markgraf, 2000). No es sorprendente entonces
que ENOS ha atraído la atención de la comunidad
científica por más de un siglo, culminando en una teoría
que describe su desarrollo y decaimiento (e.g., Neelin
et al., 1998), justificando el establecimiento de la red
de observaciones TAO-Triton y motivando el desarrollo
de la predicción climática estacional en base a modelos
estadísticos y dinámicos.
No obstante estos avances científicos y tecnológico y
nuestra capacidad de predecir la ocurrencia de eventos
Tres Niños
Sorprendentes
Dr. René Garreaud S.
SUBDIRECTOR DEL CENTRO DE INVESTIGACIÓN DEL CLIMA Y LA RESILIENCIA (CR2).
Doctor en Ciencias Atmosféricas de la Universidad de Washington, EE.UU., Magister en Geofísica
e Ingeniero de la Universidad de Chile. Es autor de más de 80 artículos publicados en revistas
internacionales y su investigación está enfocada en la dinámica del clima y meteorología de
Sudamérica. Dicta regularmente cursos de pre y posgrado en Climatología, y ha supervisado 10 postdocs.
Se ha desempeñado también como presidente del consejo superior de ciencias (FONDECYT
Chile) y presidente de la comisión de evaluación de la Facultad de Ciencias Físicas y Matemáticas de
la Universidad de Chile.
El Niño y La Niña es aun limitada, similar a la que
presentaban los pronósticos del tiempo hace unos 30
años atrás (Barnston et al., 2012). En la última década se
ha reconocido además la gran diversidad de eventos,
los que no solo difieren en su intensidad y estructura
sino que también en los mecanismos subyacentes (e.g.,
Takahashi et al., 2011; Takahashi & Dewitte 2016). Así,
ENOS no deja de sorprendernos y algunos eventos
exhiben rasgos especiales o se desarrollan sin indicios.
Ese fue el caso de tres eventos cálidos en los últimos
años: el fallido evento del 2014, El Niño Godzilla del
2015/16 y el intenso El Niño costero del verano de 2017
(Fig. 1). En este trabajo presentamos una descripción
de estos eventos, con énfasis en El Niño costero del
2017 y su posible forzante atmosférico. |
| First ANDEX Workshop | GEWEX News | Garreaud, R.; Poveda, G. | 2018 | Agua y Extremos | | http://dgf.uchile.cl/rene/PUBS/GEWEX_News_Nov2018_red.pdf | 13-15 | Vol: 29 Issue: 4 | | | | English | |
| The 2010-2015 Megadrought and its influence on the fire regime in central and south-central Chile | Ecosphere | González, M.; Gómez-González, S.; Lara, A.; Garreaud, R.; Díaz-Hormazábal, I. | 2018 | Agua y Extremos; Cambio de Uso de Suelo | 10.1002/ecs2.2300 | http://doi.wiley.com/10.1002/ecs2.2300 | e02300 | Vol: 9 Issue: 8 | 2150-8925 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Forest fire activity has increased in recent years in central and south-central Chile. Drought conditions have been associated with the increase of large wildfires, area burned and longer fire seasons. This study examines the influence of drought on fire regimes and discusses landscape management opportunities to decrease fire hazard. Specifically, we investigate the effect of the 2010–2015 Megadrought (MD) compared to 1990–2009 period on fire activity (fire-season length, number of fires and burned area across months, fire sizes, regions and vegetation cover types, simultaneity, and duration of fires) in central and south-central Chile (32°–39° S), using contemporary fire statistics derived from the Chilean Forest Service. For large fire events (>200 ha) the average season length increased by 67 d (44%), comparing 2010–2015 to 1990–2009. Earlier and later ignition dates resulted in extended fire seasons in MD years. During the MD, the number, area burned, simultaneity, and duration of large fires increased significantly compared to the control period, including the unprecedented occurrence of large fires during winter. The burned area in large fires increased in all vegetation types, during the MD compared to the control period, especially in the exotic plantation cover type. The regions that were most affected by fire (i.e., total area burned) during the MD wereMaule, B ıo-B ıo, and Araucan ıa (35–39° S) that concentrate >75% of forest plantations in Chile. Although both maximum temperatures and precipitation are drivers of fire activity, a simple attribution analysis indicates that the sustained rainfall deficit during 2010–2015 was the most critical factor in the enhanced fire activity. Future climate change predictions indicate more recurrent, intense, and temporally extended droughts for central and south-central Chile. Under this scenario, land-use planning and fire and forest management strategies must promote a more diverse and less flammable landscape mosaic limiting high load, homogenous, and continuous exotic plantations. |
| Hydroclimatic conditions trigger record harmful algal bloom in western Patagonia (summer 2016) | Scientific Reports | León-Muñoz, J.; Urbina, M.; Garreaud, R.; Iriarte, J. | 2018 | Agua y Extremos | 10.1038/s41598-018-19461-4 | http://www.nature.com/articles/s41598-018-19461-4 | art: 1330 | Vol: 8 Issue: 1 | 2045-2322 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | A harmful algal bloom (HAB) of the raphidophyta alga Pseudochattonella cf. verruculosa during the 2016 austral summer (February-March) killed nearly 12% of the Chilean salmon production, causing the worst mass mortality of fish and shellfish ever recorded in the coastal waters of western Patagonia. The HAB coincided with a strong El Ninõ event and the positive phase of the Southern Annular Mode that altered the atmospheric circulation in southern South America and the adjacent Pacific Ocean. This led to very dry conditions and higher than normal solar radiation reaching the surface. Using time series of atmospheric, hydrologic and oceanographic data we show here that an increase in surface water temperature and reduced freshwater input resulted in a weakening of the vertical stratification in the fjords and sounds of this region. This allowed the advection of more saline and nutrient-rich waters, ultimately resulting in an active harmful algal bloom in coastal southern Chile. |
| Effect of climate on tree growth in the Pampa biome of Southeastern South America: First tree-ring chronologies from Uruguay | Dendrochronologia | Lucas, C.; Puchi, P.; Profumo, L.; Ferreira, A.; Muñoz, A. | 2018 | Agua y Extremos | 10.1016/j.dendro.2018.10.004 | https://linkinghub.elsevier.com/retrieve/pii/S1125786518300249 | 113-122 | Vol: 52 | 1125-7865 | Thomson Reuters ISI (SCIE) | | English | Tree-ring research in the highland tropics and subtropics represents a major frontier for understanding climate-growth relationships. Nonetheless, there are many lowland regions – including the South American Pampa biome – with scarce tree ring data. We present the first two tree-ring chronologies for Scutia buxifolia in subtropical Southeastern South America (SESA), using 54 series from 29 trees in two sites in northern and southern Uruguay. We cross-dated annual rings and compared tree growth from 1950 to 2012 with regional climate variability, including rainfall, temperature and the Palmer Drought Severity Index – PDSI, the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). Overall, ring width variability was highly responsive to climate signals linked to water availability. For example, tree growth was positively correlated with accumulated rainfall in the summer-fall prior to ring formation for both chronologies. Summer climate conditions were key for tree growth, as shown by a negative effect of hot summer temperatures and a positive correlation with PDSI in late austral summer. The El Niño phase in late spring/early summer favored an increase in rainfall and annual tree growth, while the La Niña phase was associated with less rainfall and reduced tree growth. Extratropical climate factors such as SAM had an equally relevant effect on tree growth, whereby the positive phase of SAM had a negative effect over radial growth. These findings demonstrate the potential for dendroclimatic research and climate reconstruction in a region with scarce tree-ring data. They also improve the understanding of how climate variability may affect woody growth in native forests – an extremely limited ecosystem in the Pampa biome. |
| Onset and Evolution of Southern Annular Mode-Like Changes at Centennial Timescale | Scientific Reports | Moreno, P.; Vilanova, I.; Villa-Martínez, R.; Dunbar, R.; Mucciarone, D.; Kaplan, M.; Garreaud, R.; Rojas, M.; Moy, C.; De Pol-Holz, R.; Lambert, F. | 2018 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política | 10.1038/s41598-018-21836-6 | http://www.nature.com/articles/s41598-018-21836-6 | art: 3458 | Vol: 8 Issue: 1 | 2045-2322 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The Southern Westerly Winds (SWW) are the surface expression of geostrophic winds that encircle the southern mid-latitudes. In conjunction with the Southern Ocean, they establish a coupled system that not only controls climate in the southern third of the world, but is also closely connected to the position of the Intertropical Convergence Zone and CO2 degassing from the deep ocean. Paradoxically, little is known about their behavior since the last ice age and relationships with mid-latitude glacier history and tropical climate variability. Here we present a lake sediment record from Chilean Patagonia (51°S) that reveals fluctuations of the low-level SWW at mid-latitudes, including strong westerlies during the Antarctic Cold Reversal, anomalously low intensity during the early Holocene, which was unfavorable for glacier growth, and strong SWW since ∼7.5 ka. We detect nine positive Southern Annular Mode-like events at centennial timescale since ∼5.8 ka that alternate with cold/wet intervals favorable for glacier expansions (Neoglaciations) in southern Patagonia. The correspondence of key features of mid-latitude atmospheric circulation with shifts in tropical climate since ∼10 ka suggests that coherent climatic shifts in these regions have driven climate change in vast sectors of the Southern Hemisphere at centennial and millennial timescales. |
| Modulation of Fire Regimes by Vegetation and Site Type in Southwestern Patagonia Since 13 ka | Frontiers in Ecology and Evolution | Moreno, P.; Vilanova, I.; Villa-Martínez, R.; Francois, J. | 2018 | Agua y Extremos | 10.3389/fevo.2018.00034 | http://journal.frontiersin.org/article/10.3389/fevo.2018.00034/full | art: 34 | Vol: 6 | 2296-701X | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access; Green Open Access | English | The degree to which vegetation and site type have influenced fire regimes through the Holocene has not been investigated in detail in the temperate ecosystems of southern Patagonia. Here we present a first attempt using a paired-basin approach to study the evolution of fire regimes in sectors dominated by humid Nothofagus forests and the xeric Patagonian steppe in the Magallanes region of Chilean Patagonia (51°S). We analyzed sediment cores from two small lakes and a bog located within the same climate zone on opposite sides of the forest-steppe ecotone, ~28 km apart. The position of this biological boundary east of the Andes is controlled by the strength and position of the southern westerly winds, which constitute the sole source of precipitation throughout western Patagonia. Our results indicate that fires have occurred in the study region repeated times over the last ~13,000 years at bi- and tridecadal timescales. Sectors currently dominated by Patagonian steppe feature high frequency and low magnitude of local fires, and vice versa in humid forests. Climate-driven expansion of Nothofagus scrubland/woodland into steppe environments over the last ~4,200 years increased the magnitude and lowered the frequency of fire events, culminating with peak Nothofagus abundance, fire magnitude and frequency during the last millennium. We also detect divergences between lake-based vs. bog-based paleofire histories among paired sites located within the Patagonian steppe, ~12 km apart, which we attribute to local burning of the bog at times of lowered water table. This divergence suggests to us that bog-based vegetation and fire histories exacerbate a local, azonal, signal blurring extra-local or regional regimes, thus accounting for some discrepancies in the Quaternary paleovegetation/paleoclimate literature of southern Patagonia. |
| Past and future global transformation of terrestrial ecosystems under climate change | Science | Nolan, C.; Overpeck, J.; Allen, J.; Anderson, P.; Betancourt, J.; Binney, H.; Brewer, S.; Bush, M.; Chase, B.; Cheddadi, R.; Djamali, M.; Dodson, J.; Edwards, M.; Gosling, W.; Haberle, S.; Hotchkiss, S.; Huntley, B.; Ivory, S.; Kershaw, A.; Kim, S.; Latorre, C.; Leydet, M.; Lézine, A.; Liu, K.; Liu,... | 2018 | Agua y Extremos | 10.1126/science.aan5360 | http://www.sciencemag.org/lookup/doi/10.1126/science.aan5360 | 920-923 | Vol: 361 Issue: 6405 | 0036-8075 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Impacts of global climate change on terrestrial ecosystems are imperfectly constrained by ecosystem models and direct observations. Pervasive ecosystem transformations occurred in response to warming and associated climatic changes during the last glacial-to-interglacial transition, which was comparable in magnitude to warming projected for the next century under high-emission scenarios. We reviewed 594 published paleoecological records to examine compositional and structural changes in terrestrial vegetation since the last glacial period and to project the magnitudes of ecosystem transformations under alternative future emission scenarios. Our results indicate that terrestrial ecosystems are highly sensitive to temperature change and suggest that, without major reductions in greenhouse gas emissions to the atmosphere, terrestrial ecosystems worldwide are at risk of major transformation, with accompanying disruption of ecosystem services and impacts on biodiversity. |
| Simulaciones climáticas regionales | | Rojas, M.; Gallardo, L.; Bozkurt, D. | 2018 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política | | https://cambioclimatico.mma.gob.cl/wp-content/uploads/2020/05/Simulaciones-climaticas-regionales-2018.pdf | 27 | | | | | Spanish | El Ministerio del Medio Ambiente contrató en 2016 el presente estudio a un equipo multidisciplinario del Centro de Ciencia del Clima y la Resiliencia (CR)2 a través de la Facultad de Ciencias Físicas y Matemáticas de la Universidad de Chile, el que fue desarrollado durante el año 2017. El propósito del proyecto fue generar proyecciones climáticas para Chile a través de la modelación climática a escala regional. Dicha información busca aportar a la correcta estimación de la vulnerabilidad del país, y está disponible en una plataforma interactiva que permite apoyar el diseño de políticas públicas. Este informe de síntesis presenta los resultados del análisis de los estudios de vulnerabilidad socio-ambiental del país, y plantea una propuesta conceptual y un protocolo de estandarización para este tipo de estudios, además de algunas consideraciones generales y recomendaciones basadas en la revisión de la literatura existente sobre la vulnerabilidad de distintos sectores y ámbitos territoriales y tecnológicos del país frente al cambio climático, así como las principales vulnerabilidades institucionales y brechas de conocimiento. |
| The meanings of participation for climate change in Chile | Ambiente y Desarrollo | Sapiains Arrué, R.; Ugarte Caviedes, A.; Aldunce, P. | 2018 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.11144/Javeriana.ayd21-41.spcc | http://revistas.javeriana.edu.co/index.php/ambienteydesarrollo/article/view/22189 | 43-60 | Vol: 21 Issue: 41 | 2346-2876, 0121-7607 | Thomson Reuters ISI (ESCI) | | Spanish | This article analyzes the different meanings of the concept of participation, to move towards a more inclusive model of climate change governance in Chile. For this, a bibliographic review is presented that discusses different epistemologies, theories and definitions of participation, with emphasis on the difficulties for its implementation in the Chilean context. Subsequently, the citizen participation mechanisms deployed in the development of existing climate change governance instruments in Chile are reviewed. Types of participation used are distinguished and experiences conducted from civil society and academia are identified. Finally, the scope and limitations of the participation models implemented are discussed and the importance of increasing the influence of civil society and improving existing mechanisms is highlighted. This is explained by a climate change scenario that will possibly require a greater number of actors involved in decision-making, to anticipate possible divisions in the face of the development of more radical adaptation or mitigation actions, and that at the same time will demand higher levels of responsibility. , commitment and action of citizenship. |
| Climate variability and forest fires in central and south-central Chile | Ecosphere | Urrutia-Jalabert, R.; González, M.; González-Reyes, Á.; Lara, A.; Garreaud, R. | 2018 | Agua y Extremos; Cambio de Uso de Suelo | 10.1002/ecs2.2171 | http://doi.wiley.com/10.1002/ecs2.2171 | e02171 | Vol: 9 Issue: 4 | 2150-8925 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | This paper evaluates the relationship between fire occurrence (number and burned area) and
climate variability (precipitation and maximum temperatures) across central and south-central Chile
(32°–43° S) during recent decades (1976–2013). This region sustains the largest proportion of the Chilean
population, contains ecologically important remnants of endemic ecosystems, the largest extension of
forest exotic plantations, and concentrates most of the fire activity in the country. Fire activity in central
Chile was mainly associated with above-average precipitation during winter of the previous year and
with dry conditions during spring to summer. The later association was particularly strong in the southern,
wetter part of the study region. Maximum temperature had a positive significant relationship with
burned area across the study region, with stronger correlations toward the south. Fires in central Chile
were significantly related to El Nino~ –Southern Oscillation, through rainfall anomalies during the year
previous to the fire season. The Antarctic Oscillation during winter through summer was positively
related to fires across the study area due to drier/warmer conditions associated with the positive polarity
of this oscillation. Climate change projections for the region reveal an all-season decrease in precipitation
and increases in temperature, that may likely result in an increment of the occurrence and the area
affected by fires, as it has been observed during a multi-year drought afflicting central Chile since 2010. |
| Terrain-Trapped Airflows and Orographic Rainfall along the Coast of Northern California. Part II: Horizontal and Vertical Structures Observed by a Scanning Doppler Radar | Monthly Weather Review | Valenzuela, R.; Kingsmill, D. | 2018 | Agua y Extremos | 10.1175/MWR-D-17-0227.1 | http://journals.ametsoc.org/doi/10.1175/MWR-D-17-0227.1 | 2381-2402 | Vol: 146 Issue: 8 | 0027-0644 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | This study documents the mean properties and variability of kinematic and precipitation structures associated with orographic precipitation along the coast of Northern California in the context of terrain-trapped airflows (TTAs). TTAs are defined as relatively narrow air masses that consistently flow in close proximity and approximately parallel to an orographic barrier. Seven land-falling winter storms are examined with observations from a scanning X-band Doppler radar deployed on the coast at Fort Ross, California. Additional information is provided by a 915-MHz wind-profiling radar, surface meteorology, a GPS receiver, and balloon soundings. The composite kinematic structure during TTA conditions exhibits a significant horizontal gradient of wind direction from the coast to approximately 50 km offshore and a low-level jet (LLJ) that surmounts a weaker airflow offshore corresponding to the TTA, with a zone of enhanced precipitation evident between ~5 and 25 km offshore and oriented nearly parallel to the coastline. Conversely, the composite kinematic structure during NO-TTA conditions exhibits a smaller offshore horizontal gradient of wind direction and precipitation structures are generally enhanced within ~15 km of the coastline. Interstorm variability analysis reveals significant variations in kinematic structures during both TTA and NO-TTA conditions, whereas significant variations in precipitation structures are only evident during TTA conditions. The interstorm analysis also illustrates more clearly how LLJ vertical structures evident during NO-TTA conditions exhibit ascent along the coast and over the coastal mountains, which is in contrast to TTA conditions where the ascent occurs offshore and over the TTA. |
| Impacts of Atmospheric Rivers on Precipitation in Southern South America | Journal of Hydrometeorology | Viale, M.; Valenzuela, R.; Garreaud, R.; Ralph, F. | 2018 | Agua y Extremos | 10.1175/JHM-D-18-0006.1 | http://journals.ametsoc.org/doi/10.1175/JHM-D-18-0006.1 | 1671-1687 | Vol: 19 Issue: 10 | 1525-755X | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | This study quantifies the impact of atmospheric rivers (ARs) on precipitation in southern South America. An AR detection algorithm was developed based on integrated water vapor transport (IVT) from 6-hourly CFSR reanalysis data over a 16-yr period (2001-16). AR landfalls were linked to precipitation using a comprehensive observing network that spanned large variations in terrain along and across the Andes from 27° to 55°S, including some sites with hourly data. Along the Pacific (west) coast, AR landfalls are most frequent between 38° and 50°S, averaging 35-40 days yr-1. This decreases rapidly to the south and north of this maximum, as well as to the east of the Andes. Landfalling ARs are more frequent in winter/spring (summer/fall) to the north (south) of ~43°S. ARs contribute 45%-60% of the annual precipitation in subtropical Chile (37°-32°S) and 40%-55% along the midlatitude west coast (37°-47°S). These values significantly exceed those in western North America, likely due to the Andes being taller. In subtropical and midlatitude regions, roughly half of all events with top-quartile precipitation rates occur under AR conditions. Median daily and hourly precipitation in ARs is 2-3 times that of other storms. The results of this study extend knowledge of the key roles of ARs on precipitation, weather, and climate in the South American region. They enable comparisons with other areas globally, provide context for specific events, and support local nowcasting and forecasting. © 2018 American Meteorological Society. |
| Using the Weather Research and Forecasting (WRF) Model for Precipitation Forecasting in an Andean Region with Complex Topography | Atmosphere | Yáñez-Morroni, G.; Gironás, J.; Caneo, M.; Delgado, R.; Garreaud, R. | 2018 | Agua y Extremos | 10.3390/atmos9080304 | http://www.mdpi.com/2073-4433/9/8/304 | 304 | Vol: 9 Issue: 8 | 2073-4433 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The Weather Research and Forecasting (WRF) model has been successfully used in weather prediction, but its ability to simulate precipitation over areas with complex topography is not optimal. Consequently, WRF has problems forecasting rainfall events over Chilean mountainous terrain and foothills, where some of the main cities are located, and where intense rainfall occurs due to cutoff lows. This work analyzes an ensemble of microphysics schemes to enhance initial forecasts made by the Chilean Weather Agency in the front range of Santiago. We first tested different vertical levels resolution, land use and land surface models, as well as meteorological forcing (GFS/FNL). The final ensemble configuration considered three microphysics schemes and lead times over three rainfall events between 2015 and 2017. Cutoff low complex meteorological characteristics impede the temporal simulation of rainfall properties. With three days of lead time, WRF properly forecasts the rainiest N-hours and temperatures during the event, although more accuracy is obtained when the rainfall is caused by a meteorological frontal system. Finally, the WSM6 microphysics option had the best performance, although further analysis using other storms and locations in the area are needed to strengthen this result. |
| Temporal and spatial evaluation of long-term satellite-based precipitation products across the complex topographical and climatic gradients of Chile | Remote Sensing and Modeling of the Atmosphere, Oceans, and Interactions VII | Zambrano-Bigiarini, M. | 2018 | Agua y Extremos | 10.1117/12.2513645 | https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10782/2513645/Temporal-and-spatial-evaluation-of-long-term-satellite-based-precipitation/10.1117/12.2513645.full | 27 | Vol: 10782 | | Not indexed | | English | Satellite-based rainfall estimates (SRE) have become a promising data source to overcome some limitations of ground-based rainfall measurements, in particular for hydrological and other environmental applications. This study evaluates the spatial and temporal performance of four long-term SRE products (TMPA 3B42v7, CHIRPSv2, MSWEPv1.1 and MSWEPv2.2) over the complex topography and climatic gradients of Chile. Time series of precipitation measured at 371 stations are compared against the corresponding grid cell of each SRE (in their original spatial resolution) at different temporal scales (daily, monthly, seasonal, annual). The modified Kling-Gupta efficiency along with its three individual components were used to assess the performance of each SRE, while two categorical indices (POD, and fBIAS) were used to evaluate the skill of each SRE to correctly capture different precipitation intensities.
Results revealed that all SREs performed best in Central-Southern Chile (32.18-36.4°S), in particular at lowand mid-elevation zones (0-1000 m a.s.l.). Seasonally, all products performed best in terms of KGE0 during the wet autumn and winter seasons (MAM-JJA) compared to summer (DJF). In addition, all SREs were able to correctly identify no rain events, but during rainy days all SREs that did not use a local dataset of precipitation to recalibrate their estimates presented a low skill in providing an accurate classification of different precipitation intensities.
Overall, MSWPEPv22 showed the best performance at all time scales and country-wide, due to the use of a Chilean dataset of daily data for calibrating its precipitation estimates, making it a good candidate for hydrological applications in Chile. Finally, we conclude that when the in situ precipitation dataset used in the evaluation of different SREs does not cover the headwaters of the catchments, the obtained performances should only be considered as first guess about how well a given SRE represent the real amount of water in an area. |
| Memoria institucional 2013 - 2017 | | | 2017 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/memoria-institucional-cr2-2013-2017/ | | | | | | | |
| Local Perception of Drought Impacts in a Changing Climate: The Mega-Drought in Central Chile | Sustainability | Aldunce, P.; Araya, D.; Sapiain, R.; Ramos, I.; Lillo, G.; Urquiza, A.; Garreaud, R. | 2017 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política | 10.3390/su9112053 | http://www.mdpi.com/2071-1050/9/11/2053 | 2053 | Vol: 9 Issue: 12 | 2071-1050 | Thomson Reuters ISI (SCIE; SSCI) | All Open Access; Gold Open Access | English | Droughts are a recurrent and complex natural hazard whose frequency and magnitude are expected to increase with climate change. Despite the advances in responding and adapting to droughts (with the development of new policies, for example), droughts continue to cause serious impacts and suffering. Developing well-targeted public policies requires further research on adaptation. Specifically, understanding the public perception of drought can help to identify drivers of and barriers to adaptation and options. This research seeks to understand the public perception of drought in central Chile in order to inform adaptation-related policies and decision-making processes. This study focused on the Mega-drought, which was a protracted dry spell afflicting central Chile since 2010. |
| Modeling study of biomass burning plumes and their impact on urban air quality; a case study of Santiago de Chile | Atmospheric Environment | Cuchiara, G.; Rappenglück, B.; Rubio, M.; Lissi, E.; Gramsch, E.; Garreaud, R. | 2017 | Agua y Extremos | 10.1016/j.atmosenv.2017.07.002 | http://linkinghub.elsevier.com/retrieve/pii/S1352231017304430 | 79-91 | Vol: 166 | 13522310 | Thomson Reuters ISI (SCIE) | | English | On January 4, 2014, during the summer period in South America, an intense forest and dry pasture wildfire occurred nearby the city of Santiago de Chile. On that day the biomass-burning plume was transported by low-intensity winds towards the metropolitan area of Santiago and impacted the concentration of pollutants in this region. In this study, the Weather Research and Forecasting model coupled with Chemistry (WRF/Chem) is implemented to investigate the biomass-burning plume associated with these wildfires nearby Santiago, which impacted the ground-level ozone concentration and exacerbated Santiago's air quality. Meteorological variables simulated by WRF/Chem are compared against surface and radiosonde observations, and the results show that the model reproduces fairly well the observed wind speed, wind direction air temperature and relative humidity for the case studied. Based on an analysis of the transport of an inert tracer released over the locations, and at the time the wildfires were captured by the satellite-borne Moderate Resolution Imaging Spectroradiometer (MODIS), the model reproduced reasonably well the transport of biomass burning plume towards the city of Santiago de Chile within a time delay of two hours as observed in ceilometer data. A six day air quality simulation was performed: the first three days were used to validate the anthropogenic and biogenic emissions, and the last three days (during and after the wildfire event) to analyze the performance of WRF/Chem plume-rise model within FINNv1 fire emission estimations. The model presented a satisfactory performance on the first days of the simulation when contrasted against data from the well-established air quality network over the city of Santiago de Chile. These days represent the urban air quality base case for Santiago de Chile unimpacted by fire emissions. However, for the last three simulation days, which were impacted by the fire emissions, the statistical indices showed a decrease in the model performance. While the model showed a satisfactory evidence that wildfires plumes that originated in the vicinity of Santiago de Chile were transported towards the urban area and impacted the air quality, the model still underpredicted some pollutants substantially, likely due to misrepresentation of fire emission sources during those days. Potential uncertainties may include to the land use/land cover classifications and its characteristics, such as type and density of vegetation assigned to the region, where the fire spots are detected. The variability of the ecosystem type during the fire event might also play a role. |
| The 2010-2015 mega drought in Central Chile: Impacts on regional hydroclimate and vegetation | Hydrology and Earth System Sciences | Garreaud, R.; Alvarez-Garreton, C.; Barichivich, J.; Boisier, J.; Christie, D.; Galleguillos, M.; LeQuesne, C.; McPhee, J.; Zambrano-Bigiarini, M. | 2017 | Agua y Extremos; Cambio de Uso de Suelo | 10.5194/hess-21-6307-2017 | https://www.hydrol-earth-syst-sci-discuss.net/hess-2017-191/ | 6307-6327 | Vol: 21 Issue: 12 | 1027-5606 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access; Green Open Access | English | Since 2010 an uninterrupted sequence of dry years, with annual rainfall deficits ranging from 25 to 45 %, has prevailed in Central Chile (western South America, 30–38° S). Although intense 1- or 2-year droughts are recurrent in this Mediterranean-like region, the ongoing event stands out because of its longevity and large spatial extent. The extraordinary character of the so-called Central Chile Mega Drought (MD) was established against century long historical records and a millennial tree-ring reconstruction of regional precipitation. The largest MD-averaged rainfall relative anomalies occurred in the northern, semi-arid sector of central Chile but the event was unprecedented to the south of 35° S. ENSO neutral conditions have prevailed since 2011 (but for the strong El Niño 2015) contrasting with La Niña conditions that often accompanied past droughts. The precipitation deficit diminished the Andean snowpack and resulted in amplified declines (up to 90 %) of river flow, reservoir volumes and groundwater levels along central Chile and westernmost Argentina. In some semiarid basins we also found a conspicuous decrease in the runoff-to-rainfall coefficient. A substantial decrease in vegetation productivity occurred in the shrubland-dominated, northern sector, but a mix of greening and browning patches occurred farther south where irrigated croplands and exotic forest plantations dominate. The ongoing warming in central Chile, making the MD one of the warmest 6-year period on record, may have also contributed to such complex vegetation changes by increasing potential evapotranspiration. The understanding of the nature and biophysical impacts of the MD contributes to preparedness efforts to face a dry, warm future regional climate scenario. |
| Research on Climate Change Policies and Rural Development in Latin America: Scope and Gaps | Sustainability | Locatelli, B.; Aldunce, P.; Fallot, A.; Le Coq, J.; Sabourin, E.; Tapasco, J. | 2017 | Agua y Extremos | 10.3390/su9101831 | http://www.mdpi.com/2071-1050/9/10/1831 | 1831 | Vol: 9 Issue: 10 | 2071-1050 | Thomson Reuters ISI (SCIE; SSCI) | All Open Access; Gold Open Access | English | Research on climate change policies can contribute to policy development by building an understanding of the barriers faced in policy processes, and by providing knowledge needed throughout policy cycles. This paper explores the thematic coverage of research on climate change policies related to rural areas, rural development, and natural resource management in Latin America. A three-tier framework is proposed to analyse the selected literature. The results show that research studies have focussed on the mitigation of greenhouse gas emissions from forests, and adaptations to climate change in agriculture. There is little policy research on other vulnerable sectors (e.g., water and health) and emitting sectors (e.g., energy and industry) in the context of rural development. Our analysis highlights the various research gaps that deserve increased scientific attention, including: cross-sector approaches, multi-level governance, and the stages of policy adoption, implementation and evaluation. In addition, the selected literature has a limited contribution to theoretical discussions in policy sciences. |
| The Chilean Coastal Orographic Precipitation Experiment: Observing the Influence of Microphysical Rain Regimes on Coastal Orographic Precipitation | Journal of Hydrometeorology | Massmann, A.; Minder, J.; Garreaud, R.; Kingsmill, D.; Valenzuela, R.; Montecinos, A.; Fults, S.; Snider, J. | 2017 | Agua y Extremos | 10.1175/JHM-D-17-0005.1 | http://journals.ametsoc.org/doi/10.1175/JHM-D-17-0005.1 | 2723-2743 | Vol: 18 Issue: 10 | 1525-755X, 1525-7541 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | The Chilean Coastal Orographic Precipitation Experiment (CCOPE) was conducted during the austral winter of 2015 (May-August) in the Nahuelbuta Mountains (peak elevation 1.3 km MSL) of southern Chile (38°S). CCOPE used soundings, two profiling Micro Rain Radars, a Parsivel disdrometer, and a rain gauge network to characterize warm and ice-initiated rain regimes and explore their consequences for orographic precipitation. Thirty-three percent of foothill rainfall fell during warm rain periods, while 50% of rainfall fell during ice-initiated periods. Warm rain drop size distributions were characterized by many more and relatively smaller drops than ice-initiated drop size distributions. Both the portion and properties of warm and ice-initiated rainfall compare favorably with observations of coastal mountain rainfall at a similar latitude in California. Orographic enhancement is consistently strong for rain of both types, suggesting that seeding from ice aloft is not a requisite for large orographic enhancement. While the data suggest that orographic enhancement may be greater during warm rain regimes, the difference in orographic enhancement between regimes is not significant. Sounding launches indicate that differences in orographic enhancement are not easily explainable by differences in low-level moisture flux or nondimensional mountain height between the regimes. |
| Potencial de los anillos de crecimiento de Pilgerodendron uviferum para el estudio histórico de las Iglesias de Chiloé, Patrimonio de la Humanidad | Bosque (Valdivia) | Puchi, P.; Muñoz, A.; González, M.; Abarzúa, A.; Araya, K.; Towner, R.; Fitzek, R.; Holz, A.; Stahle, D. | 2017 | Agua y Extremos; Cambio de Uso de Suelo | 10.4067/S0717-92002017000100012 | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-92002017000100012&lng=en&nrm=iso&tlng=en | 109-121 | Vol: 38 Issue: 1 | 0717-9200 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Las iglesias de Chiloé son antiguas estructuras de madera reconocidas patrimonio de la humanidad por la UNESCO. Gran parte de su historia de construcción y reparaciones aún se desconoce. Considerando que muchas de las iglesias de Chiloé fueron construidas utilizando madera de Pilgerodendron uviferum, el objetivo de este trabajo fue evaluar el potencial de esta especie para datar piezas de madera de dos de estas históricas construcciones: las iglesias de Vilupulli e Ichuac. En Vilupulli se dataron piezas de 311 y 181 años provenientes de los pilares de la torre. Estas piezas fueron fechadas con cronologías de ancho de anillos de P. uviferum cercanas a las dos iglesias. También utilizando estas cronologías se dataron piezas de 79, 89, 97 y 135 años obtenidas a partir de los pilotes que sostienen el piso de la iglesia de Ichuac. Considerando que Vilupulli fue construida a principios del siglo XX, es posible que las muestras de la torre que presentaron fechas cercanas a 1918, sean parte del proceso tardío de construcción de la iglesia o de una restauración posterior. Por su parte, Ichuac fue construida a finales del siglo XIX, por lo que las piezas del piso que dataron entre 19201929, formarían parte de una posible restauración no descrita previamente en archivos históricos, la cual pudo ocurrir incluso varios años posterior a la fecha del anillo más reciente encontrado en las piezas estudiadas. Se concluye que P. uviferum tiene alto potencial para estudios históricos en estructuras patrimoniales en el sur de Chile. |
| Anatomic anomalies in annual tree-rings of Austrocedrus chilensis (D. Don) Pic.-Serm. et Bizzarri in its northern distribution range | Gayana. Botánica | Rojas-Badilla, M.; Álvarez, C.; Velásquez-Álvarez, G.; Hadad, M.; Le Quesne, C.; Christie, D. | 2017 | Agua y Extremos | 10.4067/S0717-66432017000200269 | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432017000200269&lng=en&nrm=iso&tlng=en | 269-281 | Vol: 74 Issue: 2 | 0717-6643 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Tree-ring anatomical anomalies have received little attention in southern South American trees, however they can contain valuable intra-annual environmental information. This study addressed for the first time the three most frequent tree- ring anomalies recorded in the northern and oldest known Austrocedrus chilensis forest in central Chile (32-35°S). Three anatomic anomalies described were: partially absent rings, intra-annual bands and frost rings. Partially absent rings resulted from cambial inactivity during a complete growing period and require dendrochronological tools to be detected. Intra- annual bands are consequence of the abundance-shortage of environmental resources during the growing season and can be detected by examining the undefined late-wood boundaries. Frost rings, are caused by extreme low temperatures and are characterized by collapsed cells in the tree-ring growth. Results indicate that the northern most population exhibited the highest rate of absent rings, while the occurrence of intra-annual bands seems to be rather minor in the study area. Finally, frost rings are registered mainly in the younger trees in all three studied sites. These results suggest the potential for future spatio-temporal studies that examine the frequency of these anatomical anomalies in A. chilensis chronologies along its wide geographical distribution. This will complement the current environmental information recorded by its growth rates. |
| Climate change and resilience of deciduous Nothofagus forests in central-east Chilean Patagonia over the last 3200 years: RESILIENCE OF DECIDUOUS NOTHOFAGUS FORESTS IN PATAGONIA | Journal of Quaternary Science | Simi, E.; Moreno, P.; Villa-Martínez, R.; Vilanova, I.; de Pol-Holz, R. | 2017 | Agua y Extremos; Cambio de Uso de Suelo | 10.1002/jqs.2948 | http://doi.wiley.com/10.1002/jqs.2948 | 845-856 | Vol: 32 Issue: 6 | 0267-8179 | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | We examine the response of Nothofagus forests to climate change and disturbance regimes over the last 3200 years near Coyhaique (45°S), central–east Chilean Patagonia, using fine‐resolution pollen and charcoal records from lake sediment cores. Closed‐canopy deciduous Nothofagus forests have dominated the region with little variation until the arrival of Chilean–European settlers, suggesting a predominance of cool‐temperate and wet conditions. Within this state we identify centennial‐scale episodes of forest fragmentation, increase in littoral macrophytes and volcanic/paleofire disturbance between 2700 and 3000 cal a BP, 2200 and 2500 cal a BP and over the last ∼250 years, which we interpret as intervals with negative hydrologic balance. Natural variability caused little impact on the physiognomy and composition of the vegetation in pre‐European time, in contrast to the accelerated shift that started during the late 19th century associated with deforestation, homogenization and synchronization of ecosystem changes at the landscape level, and spread of exotic plant species brought by Chilean and European settlers during a warm/dry interval. The resilience of deciduous Nothofagus forests to natural disturbance regimes and climate change was exceeded by large‐scale human disturbance since the late 19th century by fire, timber exploitation and livestock grazing. These disturbances caused an ecosystem shift towards artificial meadows and scrublands with frequent high‐magnitude fires. |
| Informe de devolución Valle del Aconcagua, Primera Parte: Prácticas de adaptación al cambio climático: Sequía | | Aldunce, P.; Lillo, G.; Araya, D.; Maldonado, P.; Ramos, I. | 2016 | Agua y Extremos | | https://www.cr2.cl/wp-content/uploads/2016/05/devolucion-aconcagua.pdf | 1-15 | | | | | | Uno de los principales desafíos que enfrenta la sociedad actual es el cambio climático, que ya se comienza a sentir y se proyecta en impactos como el
aumento de la temperatura media, derretimiento de
nieve y glaciares, cambios en la intensidad y temporalidad de la lluvia, disminución de las reservas de agua
dulce superficiales y de la recarga de acuíferos, olas
de calor, entre otros1.
El Valle del Aconcagua no es ajeno a esta nueva realidad climática y se enfrenta a retos que requieren del
trabajo permanente, comprometido e informado de
sus habitantes para adaptarse a los efectos del cambio climático, de modo de asegurar el bienestar presente y futuro2.
En el presente documento se entregan los resultados
del trabajo colectivo realizado con distintos actores
sociales del Valle del Aconcagua, respecto de los mecanismos y prácticas desarrolladas para adaptarse a
la sequía, así como qué podemos aprender de estas
prácticas y cómo podemos fortalecerlas a través del
aprendizaje social para aumentar las capacidades
adaptativas y de resiliencia. |
