Línea de investigación:

Agua y extremos

Los eventos extremos tienen importantes efectos en la sociedad y existe una percepción generalizada del aumento en su recurrencia en todo el país. Los eventos recientes incluyen la megasequía en la zona central y sur (2010-2016), la peor floración de algas nocivas jamás registrada en Patagonia, la temporada de incendios sin precedentes de 2017 y grandes inundaciones y deslizamientos de tierra en el centro-norte de Chile (2015 y  2017).

Cuantificar, comprender y proyectar la ocurrencia de extremos climáticos es relevante dados sus efectos en los sistemas naturales versus los sistemas alterados. Los aumentos en la población y la expansión del uso del territorio aumentan nuestra exposición a eventos extremos, y existe una necesidad urgente de estudiar y apoyar a las comunidades para pasar de la vulnerabilidad a la resiliencia.

Para avanzar en esta línea de investigación, es imperativo cuantificar el papel de la variabilidad natural y las variaciones en eventos extremos basadas ​​en datos históricos y paleo-reconstrucción. Paralelamente, buscamos atribuir el aumento aparente en la ocurrencia de eventos extremos seleccionados en las últimas décadas al forzamiento climático antropogénico, utilizando técnicas de vanguardia. Por último, nuestro objetivo es estimar los posibles cambios en la frecuencia, intensidad y duración de los eventos extremos seleccionados durante el siglo XXI.

El área de ciencias sociales de nuestro grupo trabajará para comprender cómo la sociedad, desde las comunidades locales a las autoridades nacionales, se está adaptando a los cambios en eventos extremos, a través de la investigación centrada en las prácticas actuales, su utilidad, las barreras para la implementación y las oportunidades de mejora.

INVESTIGADOR PRINCIPAL

CO-INVESTIGADORA PRINCIPAL

INVESTIGADORES ASOCIADOS

INVESTIGADOR JORNADA COMPLETA

INVESTIGADORES ADJUNTOS

INVESTIGADOR COLABORADOR

ESTUDIANTES

Nombre Apellido
André Moreau
Angélica Jara
Carolina Morano Buchner
Claudio Alvarez
David Trejo Cancino
Estefanía Pizarro
Fabiola Cid
Felipe Velden
Gabriela Andrea Guevara Cue
John Bryan Munro Gormaz
Lintsiee Carreño
María José Kaffman Barba
Monica Bello Mejía
Natalia Bolivar
Oscar Pesce
Roque Montecinos
Talia Anderson
Tomas Caballero
Valentina Stark
Dalila del Carmen Briones Soto
LEONARDO ANDRÉ VILLACÍS CUSTODIO
Lucas Hernán Glasner Vivanco

Noticias relacionadas

Línea de InvestigaciónAñoAutoresTítuloRevistaFicha de PublicaciónDOIAbstractAccesoPáginasVolumenIndexKey Words
Ciudades Resilientes; Agua y Extremos2021Henríquez, Carla A.; Moreno, Patricio I.; Lambert, Fabrice; Alloway, Brent V.The role of climate and disturbance regimes upon temperate rainforests during the Holocene: A stratigraphic perspective from Lago Fonk (∼40°S), northwestern PatagoniaQuaternary Science Reviews10.1016/j.quascirev.2021.106890https://linkinghub.elsevier.com/retrieve/pii/S0277379121000974106890258.0Thomson Reuters ISIcharcoal, explosives, fires, forestry, stratigraphy, volcanoes, centennial/millennial-scale variability, climate regime, disturbance regime, explosive volcanism, fire disturbance, holocenes, lake sediment cores, patagonia, pollen analysis, temperate rainforest, lakes, charcoal, climate variation, disturbance, explosive volcanism, fossil record, holocene, rainforest, stratigraphy, temperate forest, vegetation dynamics, chile, cumbria, england, lake district, longitudinal valley, patagonia, taiwan, united kingdom, eucryphia
Agua y Extremos2021Aguayo, Rodrigo; León-Muñoz, Jorge; Garreaud, René; Montecinos, AldoHydrological droughts in the southern Andes (40–45°S) from an ensemble experiment using CMIP5 and CMIP6 modelsScientific Reports10.1038/s41598-021-84807-4Abstract 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.http://www.nature.com/articles/s41598-021-84807-4553011.0Thomson Reuters ISI
Zonas Costeras; Agua y Extremos2021Carrasco, Jorge F.; Bozkurt, Deniz; Cordero, Raul R.A review of the observed air temperature in the Antarctic Peninsula. Did the warming trend come back after the early 21st hiatus?Polar Science10.1016/j.polar.2021.100653Recent changes in the near-surface air temperature (nSAT) in the Antarctic Peninsula (AP) suggests that the absence of 21st century warming on Antarctic Peninsula may be coming to end. To examine this, the long-term annual and seasonal variability of the nSAT at eight Antarctic stations located in the AP are analyzed using available data from the SCAR Reader database, complemented with data from the Chilean Weather Service (Frei and O’Higgins). An exponential lter was applied to the original annual and seasonal mean series to obtain a decadal-like variation of the nSAT. A stacked and the standardized anomaly of the nSAT record was constructed to examine the average regional behavior in the AP. Cumulative sum (CUSUM) and changepoint analysis were applied through the stacked nSAT series to highlight signi cant changes caused by variation in weather and climate. The CUSUM and bootstrapping analysis revealed two statistically signi cant breaking points during the 1978–2020 period. The rst one occurred in the late nineties ending a warming period and making the beginning of a cooling period; the second one may have taken place in the mid-2010s and could mark the end of the warming pause. These trends appear to be consistent with the changes observed in the large-scale climate modes (i.e., the Antarctic Annular Mode – AAO).https://linkinghub.elsevier.com/retrieve/pii/S1873965221000189100653Thomson Reuters ISIair temperature, antarctic peninsula, change point, reader database, warming and cooling trends
Cambio de Uso de Suelo; Agua y Extremos; Gobernanza e Interfaz Ciencia y Política2021Galleguillos, Mauricio; Gimeno, Fernando; Puelma, Cristóbal; Zambrano-Bigiarini, Mauricio; Lara, Antonio; Rojas, MaisaDisentangling the effect of future land use strategies and climate change on streamflow in a Mediterranean catchment dominated by tree plantationsJournal of Hydrology10.1016/j.jhydrol.2021.126047Climate 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.https://linkinghub.elsevier.com/retrieve/pii/S0022169421000949126047595.0Thomson Reuters ISIcatchments, climate models, conservation, land use, reforestation, runoff, stream flow, land use and land cover change, land-use strategies, mediterranean catchment, mediterranean ecosystem, plantation managements, protection and restoration, soil and water assessment tool, water availability, climate change, afforestation, catchment, climate change, coniferous forest, coniferous tree, land cover, land use, land use change, shrubland, soil and water assessment tool, streamflow, tree planting, mediterranean region, pinus radiata
Ciudades Resilientes; Agua y Extremos; Gobernanza e Interfaz Ciencia y Política2021Ancapichún, Santiago; De Pol-Holz, Ricardo; Christie, Duncan A.; Santos, Guaciara M.; Collado-Fabbri, Silvana; Garreaud, René; Lambert, Fabrice; Orfanoz-Cheuquelaf, Andrea; Rojas, Maisa; Southon, John; Turnbull, Jocelyn C.; Creasman, Pearce PaulRadiocarbon bomb-peak signal in tree-rings from the tropical Andes register low latitude atmospheric dynamics in the Southern HemisphereScience of The Total Environment10.1016/j.scitotenv.2021.145126South 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.https://linkinghub.elsevier.com/retrieve/pii/S0048969721001923145126774.0Thomson Reuters ISIboundary layers, carbon, forestry, topography, tropics, atmospheric dynamics, carbon reservoirs, continental carbons, geographical provenances, latitudinal gradients, southern hemisphere, tropical climates, upper troposphere, bombs (ordnance), carbon 14, atmospheric circulation, atmospheric dynamics, atmospheric modeling, carbon isotope, latitudinal gradient, paleoclimate, radiocarbon dating, southern hemisphere, tree ring, amazonas (brazil), araucaria, araucaria angustifolia, article, atmosphere, atmospheric circulation, bomb, bomb signal, carbon reservoir effect, chile, controlled study, environmental impact, environmental parameters, geographic distribution, latitude, new zealand, nonhuman, pacific ocean, plant structures, polylepis tarapacana, priority journal, rosaceae, southern hemisphere, surface topography, topography, tree ring, troposphere, turnover rate, bomb, brazil, sea, tree, amazon basin, andes, brazil, new zealand, pacific ocean, bombs, brazil, oceans and seas, pacific ocean, trees
Zonas Costeras; Agua y Extremos2021Bozkurt, Deniz; Bromwich, David H.; Carrasco, Jorge; Rondanelli, RobertoTemperature and precipitation projections for the Antarctic Peninsula over the next two decades: contrasting global and regional climate model simulationsClimate Dynamics10.1007/s00382-021-05667-2This 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.http://link.springer.com/10.1007/s00382-021-05667-2Thomson Reuters ISIair temperature, climate change, climate modeling, cmip, downscaling, extreme event, global climate, precipitation assessment, regional climate, antarctic peninsula, antarctica, larsen ice shelf, west antarctica
Agua y Extremos2021Benra, F.; De Frutos, A.; Gaglio, M.; Álvarez-Garretón, C.; Felipe-Lucia, M.; Bonn, A.Mapping water ecosystem services: Evaluating InVEST model predictions in data scarce regionsEnvironmental Modelling & Software10.1016/j.envsoft.2021.104982Sustainable 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.https://linkinghub.elsevier.com/retrieve/pii/S1364815221000256104982138.0Thomson Reuters ISIecosystems, forecasting, hydrogeology, land use, water management, water supply, climatic variation, land-use change, model prediction, pearson correlation, sustainable management, temporal variation, water ecosystems, water monitoring, decision making, decision support system, ecosystem service, estimation method, least squares method, performance assessment, prediction, streamflow, sustainable development, water supply, chile
Agua y Extremos2021Díaz, Patricio A.; Peréz-Santos, Iván; Álvarez, Gonzalo; Garreaud, René; Pinilla, Elías; Díaz, Manuel; Sandoval, Alondra; Araya, Michael; Álvarez, Francisco; Rengel, José; Montero, Paulina; Pizarro, Gemita; López, Loreto; Iriarte, Luis; Igor, Gabriela; Reguera, BeatrizMultiscale physical background to an exceptional harmful algal bloom of Dinophysis acuta in a fjord systemScience of The Total Environment10.1016/j.scitotenv.2021.145621Dinophysis 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.https://linkinghub.elsevier.com/retrieve/pii/S0048969721006896145621773.0Thomson Reuters ISIalgae control, oceanography, plankton, plants (botany), population statistics, residence time distribution, shellfish, surface waters, diarrhetic shellfish poisoning, harmful algal blooms, long-term climate variability, mesoscale distribution, phytoplankton distributions, southern annular mode, thermally stratified, water residence time, protozoa, alga, algal bloom, climate effect, climate variation, flagellate, geographical distribution, growth rate, poisoning, population dynamics, southern hemisphere, toxin, alga, algal bloom, algal growth, article, chile, climate change, dinophysis acuta, environmental monitoring, hydrography, meteorological phenomena, microplankton, nonhuman, physical parameters, priority journal, salinity, sea surface temperature, seasonal variation, southern hemisphere, species distribution, thermoregulation, water residence time, algal bloom, dinoflagellate, estuary, human, chile, patagonia, dinophysis acuta, shellfish poisoning, chile, dinoflagellida, estuaries, harmful algal bloom, humans, shellfish poisoning
Agua y Extremos2021Alvarez-Garreton, Camila; Boisier, Juan Pablo; Garreaud, René; Seibert, Jan; Vis, MarcProgressive water deficits during multiyear droughts in basins with long hydrological memory in ChileHydrology and Earth System Sciences10.5194/hess-25-429-2021Abstract. 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.https://hess.copernicus.org/articles/25/429/2021/429-44625.0Thomson Reuters ISIcatchments, groundwater, runoff, snow, stream flow, water supply, annual precipitation, catchment characteristics, hydrological modeling, limited water supplies, meteorological condition, meteorological drought, precipitation anomalies, precipitation deficits, drought, catchment, drought, groundwater-surface water interaction, hydrological modeling, meteorology, precipitation (climatology), rainfall, runoff, snowmelt, streamflow, chile
Cambio de Uso de Suelo; Agua y Extremos2021Barría, Pilar; Chadwick, Cristián; Ocampo-Melgar, Anahí; Galleguillos, Mauricio; Garreaud, Rene; Díaz-Vasconcellos, Raúl; Poblete, David; Rubio-Álvarez, Eduardo; Poblete-Caballero, DagobertoWater management or megadrought: what caused the Chilean Aculeo Lake drying?Regional Environmental Change10.1007/s10113-021-01750-wThe 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.http://link.springer.com/10.1007/s10113-021-01750-w1921.0Thomson Reuters ISIanthropogenic, attribution, decision making, drought, land use/land cover, water budget
Agua y Extremos2021Rojas, Yazmina; Minder, Justin R.; Campbell, Leah S.; Massmann, Adam; Garreaud, ReneAssessment of GPM IMERG satellite precipitation estimation and its dependence on microphysical rain regimes over the mountains of south-central ChileAtmospheric Research10.1016/j.atmosres.2021.105454Satellite 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.https://linkinghub.elsevier.com/retrieve/pii/S0169809521000065105454253.0Thomson Reuters ISIdeveloping countries, ice, landforms, meteorological radar, radar measurement, rain gages, satellites, space-based radar, topography, complex topographies, global precipitation measurements, ground based sensors, ground-based observations, orographic enhancement, orographic precipitation, quantitative precipitation estimation, satellite precipitation, rain, assessment method, cloud microphysics, estimation method, precipitation assessment, satellite data, satellite imagery, spatiotemporal analysis, chile
Agua y Extremos2021Matskovsky, V.; Venegas-González, A.; Garreaud, R.; Roig, Fidel A.; Gutiérrez, Alvaro G.; Muñoz, Ariel A; Le Quesne, C.; Klock, K.; Canales, C.Tree growth decline as a response to projected climate change in the 21st century in Mediterranean mountain forests of ChileGlobal and Planetary Change10.1016/j.gloplacha.2020.103406Global 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.https://www.sciencedirect.com/science/article/abs/pii/S092181812030297613198.0Thomson Reuters ISIclimate models, ecosystems, forestry, landforms, climate change projections, deleterious effects, endangered tree species, global climate model, mediterranean forest, mediterranean mountains, process-based modeling, tree growth modeling, climate change, biome, chronology, climate change, climate modeling, deciduous tree, dieback, extreme event, forest ecosystem, global change, global climate, growth, mediterranean environment, montane forest, tree, tree ring, twenty first century, chile, austrocedrus chilensis, nothofagus macrocarpa
Agua y Extremos2021Moreno, Patricio I.; Videla, Javiera; Kaffman, María José; Henríquez, Carla A.; Sagredo, Esteban A.; Jara-Arancio, Paola; Alloway, Brent V.Vegetation, disturbance, and climate history since the onset of ice-free conditions in the Lago Rosselot sector of Chiloé continental (44°S), northwestern PatagoniaQuaternary Science Reviews10.1016/j.quascirev.2021.106924We 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.https://linkinghub.elsevier.com/retrieve/pii/S0277379121001311106924260.0Thomson Reuters ISIclimate change, explosives, glacial geology, lakes, volcanoes, chiloe continental, disturbance paleoecology, glacier advance during the antarctic cold reversal, northwestern patagonium, patagonia, postglacial explosive volcanism, recession and stabilization during young dryas, vegetation and fire history, vegetation history, vegetation response, vegetation, climate forcing, disturbance, environmental change, environmental history, lacustrine deposit, sediment core, tephra, vegetation history, andes, chile, chiloe island, los lagos, patagonia
Zonas Costeras; Agua y Extremos2021Aguirre, Catalina; Flores-Aqueveque, Valentina; Vilches, Pablo; Vásquez, Alicia; Rutllant, José A.; Garreaud, RenéRecent Changes in the Low-Level Jet along the Subtropical West Coast of South AmericaAtmosphere10.3390/atmos12040465Surface 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.https://www.mdpi.com/2073-4433/12/4/46546512.0Thomson Reuters ISIatmospheric pressure, tropics, central chile, coastal ocean environment, extratropical, long-term trend, low level jet, south america, surface winds, wind events, ecosystems, algorithm, anticyclone, climate modeling, coastal zone, jet, long-term change, surface wind, upwelling, chile
Ciudades Resilientes; Agua y Extremos2021Aldunce, Paulina; Lillo-Ortega, Gloria; Araya-Valenzuela, Dámare; Maldonado-Portilla, Pamela; Gallardo, LauraEvaluating adaptation to drought in a changing climate: experience at the local scale in the Aconcagua ValleyClimate and Development10.1080/17565529.2021.1893150Since 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.https://www.tandfonline.com/doi/full/10.1080/17565529.2021.18931501-12Thomson Reuters ISIchile, climate change, drought, evaluation of adaptation, index for the usefulness of adaptation practices (iupa)
Zonas Costeras; Agua y Extremos2021Demortier, Alan; Bozkurt, Deniz; Jacques-Coper, MartínIdentifying key driving mechanisms of heat waves in central ChileClimate Dynamics10.1007/s00382-021-05810-zThis 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.https://link.springer.com/10.1007/s00382-021-05810-zThomson Reuters ISIatmospheric teleconnections, blocking pattern, central chile, heat waves, mjo, temperature extremes
Agua y Extremos2021Villa-Martínez, Rodrigo; Moreno, Patricio I.Development and resilience of deciduous Nothofagus forests since the Last Glacial Termination and deglaciation of the central Patagonian AndesPalaeogeography, Palaeoclimatology, Palaeoecology10.1016/j.palaeo.2021.110459Resolving 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.https://linkinghub.elsevier.com/retrieve/pii/S0031018221002443110459574.0Thomson Reuters ISIdeciduous forest, deglaciation, ecosystem resilience, forest canopy, glacial lake, holocene, last glacial maximum, proglacial environment, sediment core, andes, coihaique, patagonia, coniferophyta, nothofagus
Agua y Extremos2021Bozkurt, D.; Sen, O. L.; Ezber, Y.; Guan, B.; Viale, M.; Caglar, F.Influence of African Atmospheric Rivers on Precipitation and Snowmelt in the Near East's HighlandsJournal of Geophysical Research: Atmospheres10.1029/2020JD033646Atmospheric 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>275kg m1 s1). AR days exhibit enhanced precipitation over the crescent-shaped orography of the NE region. Mean AR days indicate wetter (up to+2mm day1) 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.https://onlinelibrary.wiley.com/doi/10.1029/2020JD033646126.0Thomson Reuters ISIairflow, anticyclone, atmospheric moisture, hydrometeorology, orography, precipitation assessment, snowmelt, trough, water vapor, balkans, indian ocean, mesopotamia, north africa, red sea [indian ocean], taurides, turkey, zagros
Agua y Extremos2021Guerrero, Fabián; Hernández, Carla; Toledo, Mario; Espinoza, Lorena; Carrasco, Yulian; Arriagada, Andrés; Muñoz, Ariel; Taborga, Lautaro; Bergmann, Jan; Carmona, CamiloLeaf Thermal and Chemical Properties as Natural Drivers of Plant Flammability of Native and Exotic Tree Species of the Valparaíso Region, ChileInternational Journal of Environmental Research and Public Health10.3390/ijerph18137191Forest 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.https://www.mdpi.com/1660-4601/18/13/7191719118.0Thomson Reuters ISIaliphatic hydrocarbon, fire behavior, fire management, forest fire, leaf, mediterranean environment, metabolite, physicochemical property, risk assessment, vegetation classification, chile, valparaiso [chile], acacia dealbata, cryptocarya alba, eucalyptus globulus, pinus radiata, quillaja saponaria, radiata, saponaria, chile, fire, forest, plant leaf, southern europe, tree, chile, fires, forests, mediterranean region, plant leaves, trees
Agua y Extremos2021Pérez-Santos, Iván; Díaz, Patricio A.; Silva, Nelson; Garreaud, René; Montero, Paulina; Henríquez-Castillo, Carlos; Barrera, Facundo; Linford, Pamela; Amaya, Constanza; Contreras, Sergio; Aracena, Claudia; Pinilla, Elías; Altamirano, Robinson; Vallejos, Luis; Pavez, Javiera; Maulen, JuanOceanography time series reveals annual asynchrony input between oceanic and estuarine waters in Patagonian fjordsScience of The Total Environment10.1016/j.scitotenv.2021.149241The 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.https://linkinghub.elsevier.com/retrieve/pii/S004896972104314X149241798.0Thomson Reuters ISIbiochemical oxygen demand, dissolved oxygen, economics, ecosystems, estuaries, eutrophication, observatories, oceanography, phytoplankton, time series, atmospheric mode, biogeochemicals, column stability, estuarine waters, marine observatories, oceanic waters, patagonian fjord, southern hemisphere, times series, water columns, biogeochemistry, oxygen, picnocline, unclassified drug, water, annual variation, biogeochemistry, estuarine dynamics, estuarine environment, eutrophication, fjord, land-atmosphere interaction, land-sea interaction, nearshore dynamics, physical oceanography, southern hemisphere, time series, water column, water mass, westerly, air conditioning, aquaculture, aquatic environment, article, atmosphere, biogeochemical cycle, cell polarity, controlled study, estuary, falling, inorganic nutrient, nonhuman, oceanography, ph, physical chemistry, phytoplankton, salinity, subsurface runoff, summer, time series analysis, water column stability, winter, south america
Agua y Extremos2021Soto, Doris; León-Muñoz, Jorge; Garreaud, René; Quiñones, Renato A.; Morey, FranciscoScientific warnings could help to reduce farmed salmon mortality due to harmful algal bloomsMarine Policy10.1016/j.marpol.2021.104705The 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.https://linkinghub.elsevier.com/retrieve/pii/S0308597X2100316X104705132.0Thomson Reuters ISIalgal bloom, aquaculture industry, aquaculture production, climate effect, coastal zone, eutrophication, governance approach, mariculture, mortality, risk assessment, salmonid culture, chile
Zonas Costeras; Agua y Extremos2021Scheiter, Matthias; Schaefer, Marius; Flández, Eduardo; Bozkurt, Deniz; Greve, RalfThe 21st-century fate of the Mocho-Choshuenco ice cap in southern ChileThe Cryosphere10.5194/tc-15-3637-2021Abstract. 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.https://tc.copernicus.org/articles/15/3637/2021/3637-365415.0Thomson Reuters ISIclimate modeling, deglaciation, equilibrium line, glacier dynamics, ice cap, ice sheet, surface temperature, twenty first century, andes, los rios [chile], mocho-choshuenco, southern volcanic zone
Agua y Extremos2021McNamara, Ian; Baez-Villanueva, Oscar M.; Zomorodian, Ali; Ayyad, Saher; Zambrano-Bigiarini, Mauricio; Zaroug, Modathir; Mersha, Azeb; Nauditt, Alexandra; Mbuliro, Milly; Wamala, Sowed; Ribbe, LarsHow well do gridded precipitation and actual evapotranspiration products represent the key water balance components in the Nile Basin?Journal of Hydrology: Regional Studies10.1016/j.ejrh.2021.100884Study 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.https://linkinghub.elsevier.com/retrieve/pii/S221458182100113010088437.0Thomson Reuters ISIevapotranspiration, grace, precipitation, random forest, remote sensing, water balance
Cambio de Uso de Suelo; Agua y Extremos; Gobernanza e Interfaz Ciencia y Política2021Hoyos-Santillan, Jorge; Miranda, Alejandro; Lara, Antonio; Sepulveda-Jauregui, Armando; Zamorano-Elgueta, Carlos; Gómez-González, Susana; Vásquez-Lavín, Felipe; Garreaud, Rene D.; Rojas, MaisaDiversifying Chile’s climate action away from industrial plantationsEnvironmental Science & Policy10.1016/j.envsci.2021.06.013As 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.https://linkinghub.elsevier.com/retrieve/pii/S146290112100173885-89124.0Thomson Reuters ISIcarbon, biodiversity, building, carbon footprint, carbon sequestration, carbon sink, carbon source, chile, climate, climate change, drought, electric power plant, energy yield, forest, forestry, housing, land use, note, peatland, plantation, sea, tree, wetland, wildfire
Zonas Costeras; Agua y Extremos2021Aguirre, Catalina; Garreaud, René; Belmar, Lucy; Farías, Laura; Ramajo, Laura; Barrera, FacundoHigh-Frequency Variability of the Surface Ocean Properties Off Central Chile During the Upwelling SeasonFrontiers in Marine Science10.3389/fmars.2021.702051The 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.https://www.frontiersin.org/articles/10.3389/fmars.2021.702051/full7020518.0Thomson Reuters ISIair-sea exchanges, biogeochemical properties, coastal buoy observations, coastal upwelling, coastal winds, eastern boundary conditions, sub-seasonal variability
Agua y Extremos2021Anderson, Talia G.; Christie, Duncan A.; Chávez, Roberto O.; Olea, Matias; Anchukaitis, Kevin J.Spatiotemporal Peatland Productivity and Climate Relationships Across the Western South American AltiplanoJournal of Geophysical Research: Biogeosciences10.1029/2020JG005994The 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.https://onlinelibrary.wiley.com/doi/10.1029/2020JG005994126.0Thomson Reuters ISIatmospheric circulation, climate change, growing season, ndvi, peatland, precipitation (chemistry), precipitation (climatology), rainfall, snow accumulation, spatiotemporal analysis, altiplano, indicator indicator, varanidae
Cambio de Uso de Suelo; Agua y Extremos2021Bertin, Lizette J.; Christie, Duncan A.; Sheppard, Paul R.; Muñoz, Ariel A.; Lara, Antonio; Alvarez, ClaudioChemical Signals in Tree Rings from Northern Patagonia as Indicators of Calbuco Volcano Eruptions since the 16th CenturyForests10.3390/f12101305The 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.https://www.mdpi.com/1999-4907/12/10/1305130512.0Thomson Reuters ISIforestry, indicators (chemical), inductively coupled plasma, mass spectrometry, chemical signals, fitzroya cupressoides, inductively coupled plasma-mass spectrometry, northern patagonia, risk classification, sub-plinian eruption, tree rings, volcanic eruptions, volcanic explosivity indices, volcano eruptions, volcanoes
Zonas Costeras; Agua y Extremos2021Sparaventi, Erica; Rodríguez-Romero, Araceli; Barbosa, Andrés; Ramajo, Laura; Tovar-Sánchez, AntonioTrace elements in Antarctic penguins and the potential role of guano as source of recycled metals in the Southern OceanChemosphere10.1016/j.chemosphere.2021.131423Penguins dominate the Antarctic avifauna. As key animals in the Antarctic ecosystem, they are monitored to evaluate the ecological status of this pristine and remote region and specifically, they have been used as effective bioindicators suitable for long-term monitoring of metals in the Antarctic environment. However, studies about the role of this emblematic organism could play in the recycling of trace metals (TMs) in the Antarctic ecosystem are very limited. In this study we evaluate, using the peer review research articles already published and our own findings, the distribution of metals (i.e., Ca, Fe, Al, Na, Zn, Mg, Cu, K, Cd, Mn, Sr, Cr, Ni, Pb, Hg, V, Ba, Co, La, Ag, Rb, Hf, Sc, Au and Cs) and metalloids (As and Sb), measured in different biotic matrices, with emphasis on guano, of the Chinstrap (Pygoscelis antarcticus), Adélie (Pygoscelis adeliae) and Gentoo (Pygoscelis papua) penguins. Regarding bioactive metals, the high concentrations (μg g−1 dry weight) of Cu (2.0 ± 1.4) x 102, Fe (4.1 ± 2.9) x 102, Mn (30 ± 34) and Zn (210 ± 90) reported in the guano from all the penguin species studied including our data, are of the same order of magnitude as those reported for whale feces (μg g−1 dry weight): Cu (2.9 ± 2.4) x 102, Fe (1.5 ± 1.4) x 102, Mn (28 ± 17) and Zn (6.2 ± 4.3) x 102, and one order of magnitude higher than the metal contents in krill (μg g−1 dry weight) of Cu (10.2 ± 5.5), Fe (24 ± 29) and Zn (13.5 ± 1.7). This suggest that penguin's excretion products could be an important source of these essential elements in the surface water, with an estimated annual release on a breeding season for Cu, Fe, Mn, Zn respectively of 28, 56, 4 and 29 tons, for the Chinstrap, Adélie and Gentoo penguins. The results provide evidence on the potential influence of penguins recycling TMs in the surface layer of the water column.https://linkinghub.elsevier.com/retrieve/pii/S0045653521018956131423285.0Thomson Reuters ISIecosystems, recycling, surface waters, trace elements, antarctica, dropping, dry weight, ecological status, metal concentrations, orders of magnitude, remote regions, southern ocean, trace metal, traces elements, metals, avifauna, bioindicator, breeding season, concentration (composition), excretion, feces, guano, metalloid, recycling, seabird, trace element, whale, southern ocean, pygoscelis antarcticus, spheniscidae
Agua y Extremos2021Henríquez, Carla A.; Moreno, Patricio I.; Dunbar, Robert B.; Mucciarone, David A.The last glacial termination in northwestern Patagonia viewed from the Lago Fonk (∼40°S) recordQuaternary Science Reviews10.1016/j.quascirev.2021.107197The 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.https://linkinghub.elsevier.com/retrieve/pii/S0277379121004042107197271.0Thomson Reuters ISIfires, forestry, glacial geology, lakes, 'current, lake levels, lake sediment cores, last glacial maximum, last glacial terminations, midlatitudes, multi proxies, multi-proxy index, patagonia, southern westerly winds, charcoal, coniferophyta, eucryphia, myrtaceae, nothofagus, podocarpus nubigenus, weinmannia trichosperma