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

INVESTIGADORES JORNADA COMPLETA

INVESTIGADORES ADJUNTOS

INVESTIGADORES POSTDOCTORALES

ESTUDIANTES

Nombre Apellido
André Moreau
Carla Henriquez
Carolina Morano Buchner
Claudio Andres Alvarez Pacheco
Emilia Fercovic
Fabiola Cid
Felipe Velden
Felipe Matus
Lizette Berlín
María José Kaffman
Monica Bello Mejía
Oscar Pesce
Piero Mardones
Roque Montecinos
Talia Anderson

Noticias relacionadas a esta línea

Línea de InvestigaciónAñoAutoresTítuloRevistaFicha de PublicaciónKey WordsISSNAbstractAccesoPáginasVolumenIndex
Agua y Extremos; Gobernanza e Interfaz entre Ciencia y Política2017Aldunce, P., Araya, D., Sapiain, R., Ramos, I., Lillo, G., Urquiza, A., Garreaud, R.Local Perception of Drought Impacts in a Changing Climate: The Mega-Drought in Central Chile
Sustainability
adaptation policy and practice, chile, climate change impacts, drought, perception, climate change, climate effect, decision making, drought, natural hazard, perception, policy development, social policy, chile2071-1050
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.http://www.mdpi.com/2071-1050/9/11/20532053vol.9Thomson Reuters ISI
Agua y Extremos2017Borquéz González, RInterfaz ciencia-políticas públicas en Chile: una mirada a la investigación en cambio climáticoRevista Colombiana de Sociología2256-5485, 0120-159XEn las últimas décadas, se han observado importantes cambios en torno a la relación entre la ciencia y la sociedad. Se ha transitado de un paradigma basado en que la ciencia está transformando la sociedad a otro que abre a la posibilidad de que la sociedad transforme la ciencia. El aporte de la esfera científica, al igual que el brindado por cada uno de los actores sociales, es fundamental para apoyar la toma de decisiones en política pública. Así lo ha demostrado el Panel Intergubernamental de Expertos sobre Cambio Climático (IPCC), que ha jugado un rol clave en la toma de acciones de la comunidad internacional. Sin embargo, la relación entre ciencia y política no ha sido suficientemente fluida en Chile. El objetivo del estudio fue identificar y analizar, a través de motodología cualitativa de carácter exploratorio, las brechas y los facilitadores de la relación entre investigadores del campo de las ciencias naturales y las políticas públicas en Chile, con énfasis en el área del cambio climático. Esto permitió analizar la estructura y la dinámica de incentivos a la actividad de las esferas científica y pública, y los mecanismos de comunicación y coordinaci;ón existentes entre ellas. Así, se identificaron ocho brechas y dos facilitadores. Resaltan el bajo interés de la esfera científica en realizar "asesorías" solicitadas por servicios públicos que generan poíticas públicas, la falta de incentivos o exigencias académicas para simplificar contenidos, así como la falta de comunicación y de interacción regular que generan una diferencia entre lo que la esfera político-administrativa espera de los científicos y la forma en que estos últimos ven como efectiva y útil su participación. Además, se observaron fallas de coordinación entre quien financia la investigación y quien genera la política pública. Los resultados también muestran que las brechas entre las esferas no se recducen únicamente al campo del cambio climático, sino que se deben también a la manera como están conformadas las estructuras científicas y políticas de Chile.https://revistas.unal.edu.co/index.php/recs/article/view/66402311-332vol.40Not indexed
Agua y Extremos2017Cuchiara, G. C., Rappenglück, B., Rubio, M. A., Lissi, E., Gramsch, E., Garreaud, R. D.Modeling study of biomass burning plumes and their impact on urban air quality; a case study of Santiago de ChileAtmospheric EnvironmentVer fichaatmospheric modeling, biomass burning, plume rise model, wrf/chem, air quality, atmospheric humidity, atmospheric temperature, biomass, image reconstruction, meteorological instruments, pollution, radiometers, radiosondes, satellite imagery, weather forecasting, anthropogenic and biogenic emissions, atmospheric model, biomass-burning, ground level ozone concentration, moderate resolution imaging spectroradiometer, plume rise, weather research and forecasting models, wrf/chem, fires, ozone, air quality, anthropogenic effect, atmospheric modeling, atmospheric plume, biogenic emission, biomass burning, forecasting method, metropolitan area, modis, radiosonde, urban pollution, air temperature, article, circadian rhythm, combustion, humidity, land use, pasture, plume, priority journal, sensitivity analysis, simulation, summer, urban area, wind, chile, metropolitana, santiago metropolitana1352-2310On 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.http://linkinghub.elsevier.com/retrieve/pii/S135223101730443079-91vol.166Thomson Reuters ISI
Agua y Extremos; Cambio de Uso de Suelo2017Garreaud, R., Alvarez-Garreton, C., Barichivich, J., Boisier, J. P., Christie, D., Galleguillos, M., LeQuesne, C., McPhee, J., Zambrano-Bigiarini, M.The 2010-2015 mega drought in Central Chile: Impacts on regional hydroclimate and vegetationHydrology and Earth System Sciences Discussions1812-2116Since 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.https://www.hydrol-earth-syst-sci-discuss.net/hess-2017-191/1-37Thomson Reuters ISI
Agua y Extremos2017González, S., Garreaud, R.Spatial variability of near-surface temperature over the coastal mountains in southern Chile (38°S)Meteorology and Atmospheric PhysicsVer fichaair temperature, computer simulation, in situ measurement, mountain, spatial distribution, surface temperature, winter, chile, coastal cordillera, cordillera de nahuelbuta0177-7971The 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.http://link.springer.com/10.1007/s00703-017-0555-4Thomson Reuters ISI
Agua y Extremos2017Locatelli, B., Aldunce, P., Fallot, A., Le Coq, J. F., Sabourin, E., Tapasco, J.Research on Climate Change Policies and Rural Development in Latin America: Scope and GapsSustainabilityadaptation, agriculture, forest, mitigation, natural resources, policy research, adaptive management, climate change, environmental policy, forest edge, greenhouse gas, natural resource, policy development, policy implementation, research work, resource management, rural area, rural development, latin america2071-1050Research 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.http://www.mdpi.com/2071-1050/9/10/18311831vol.9Thomson Reuters ISI
Agua y Extremos2017Massmann, A. K., Minder, J.R., Garreaud, R. D., Kingsmill, D. E., Valenzuela, R. A., Montecinos, A., Fults, S. L., Snider, J. R.The Chilean Coastal Orographic Precipitation Experiment: Observing the Influence of Microphysical Rain Regimes on Coastal Orographic PrecipitationJournal of HydrometeorologyVer fichacloud microphysics, coastal meteorology, drop size distribution, mountain meteorology, orographic effects, stratiform clouds, cloud microphysics, coastal zone, marine atmosphere, orographic effect, precipitation (climatology), precipitation assessment, size distribution, stratiform cloud, chile1525-755XThe 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.http://journals.ametsoc.org/doi/10.1175/JHM-D-17-0005.12723-2743vol.18Thomson Reuters ISI
Agua y Extremos, Cambio de Uso de Suelo2017Puchi, P., Muñoz, A. A., González, M. E., Abarzúa, A., Araya, K., Towner, R., Fitzek, R., Holz, A., Stahle, D.Potencial de los anillos de crecimiento de Pilgerodendron uviferum para el estudio histórico de las Iglesias de Chiloé, Patrimonio de la HumanidadBosquedendroarchaeology, historical structures, pilgerodendron uviferum0717-9200Las 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.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-92002017000100012&lng=en&nrm=iso&tlng=en109-121vol.38Thomson Reuters ISI
Agua y Extremos2017Rojas-Badilla, M., Álvarez, C., Velásquez-Álvarez, G., Hadad, M., Le Quesne, C., Christie, D. A.Anomalías anatómicas en anillos de crecimiento anuales de Austrocedrus chilensis (D. Don) Pic.-Serm. et Bizzarri en el norte de su rango de distribuciónGayana. Botánicaabsent rings, dendrochronology, frost rings, intra-annual bands, wood anatomy0717-6643Tree-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.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432017000200269&lng=en&nrm=iso&tlng=en269-281vol.74 is.2Thomson Reuters ISI, ScieLO
Agua y Extremos; Cambio de Uso de Suelo2017Simi, E., Moreno, P. I., Villa-Martínez, R., Vilanova, I., de Pol-Holz, R.Climate change and resilience of deciduous Nothofagus forests in central-east Chilean Patagonia over the last 3200 years: RESILIENCE OF DECIDUOUS NOTHOFAGUS FORESTS IN PATAGONIAJournal of Quaternary Sciencehuman disturbance, nothofagus forests, paleofires, resilience, tephras, climate variation, deciduous forest, disturbance, fire history, holocene, human activity, paleoclimate, paleoenvironment, tephra, chile, patagonia, nothofagus0267-8179We 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.http://doi.wiley.com/10.1002/jqs.2948845-856vol.32 is.6Thomson Reuters ISI
Agua y Extremos2018Baez-Villanueva, O. M., Zambrano-Bigiarini, M., Ribbe, L., Nauditt, A., Giraldo-Osorio, J.D., Thinh, N.X.
Temporal and spatial evaluation of satellite rainfall estimates over different regions in Latin-America
Atmospheric Research
0169-8095In 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.
http://linkinghub.elsevier.com/retrieve/pii/S0169809517313029Thomson Reuters ISI
Agua y Extremos2018Barria, P., Peel, M. C., Walsh, K. J. E., Muñoz, A.The first 300-year streamflow reconstruction of a high-elevation river in Chile using tree ringsInternational Journal of Climatologyhigh-elevation hydrology, multi-decadal variability, runoff reconstruction, catchments, climate change, digital storage, drought, forestry, melting, stream flow, water supply, decadal variability, high elevation, meteorological station, negative correlation, pacific decadal oscillation, positive correlations, southern annular mode, tree-ring chronologies, runoff, chronology, decadal variation, hydrology, reconstruction, river, streamflow, tree ring, chile, araucaria araucana0899-8418In 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.http://doi.wiley.com/10.1002/joc.5186436-451vol.38 is.1Thomson Reuters ISI
Agua y Extremos; Zonas Costeras; Transversal
2018Bozkurt, D., Rondanelli, R., Marín, J. C., Garreaud, R.
Foehn Event Triggered by an Atmospheric River Underlies Record-Setting Temperature Along Continental AntarcticaJournal of Geophysical Research: Atmospheresatmospheric river, climate variability, extreme high temperature, foehn wind, meteorology, regional climate modeling, advection, atmospheric moisture, climate change, climate modeling, extreme event, foehn, high temperature, ice shelf, meteorology, modis, regional climate, temperature, amundsen sea, antarctic peninsula, antarctica, bellingshausen sea, pacific ocean, pacific ocean (southeast), southern ocean, west antarctica, esperanza2169-897XA 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.http://doi.wiley.com/10.1002/2017JD0277963871-3892vol.123 is.8Thomson Reuters ISI
Agua y Extremos2018Büntgen, U., Wacker, L., Galván, J. D., Arnold, S., Arseneault, D., Baillie, M., Beer, J., Bernabei, M., Bleicher, N., Boswijk, G., Bräuning, A., Carrer, M., Ljungqvist, F. C., Cherubini, P., Christl, M., Christie, D. A., et al.Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CENature Communicationscarbon 14, carbon isotope, chronology, concentration (composition), cosmogenic radionuclide, solar radiation, spatiotemporal analysis, tree ring, article, atmospheric radioactivity, chronology, proton radiation, radiation measurement, radiometric dating, space, spring, summer, weather2041-1723Though 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.http://www.nature.com/articles/s41467-018-06036-0vol.9 is.1Thomson Reuters ISI
Agua y Extremos2018Fernández, A., Muñoz, A., González-Reyes, A., Aguilera-Betti, I., Toledo, I., Puchi, P., Sauchyn, D., Crespo, S., Frene, C., Mundo, I., González, M., Vignola, R.Dendrohydrology and water resources management in south-central Chile: lessons from the Río Imperial streamflow reconstructionHydrology and Earth System Sciencesdrought, forestry, stream flow, accurate estimation, forestry production, hydrological regime, hydrological scenarios, southern annular mode, streamflow variability, tree-ring reconstruction, water resources management, water resources, climate signal, dendrochronology, drought, hydrological regime, paleohydrology, reconstruction, snowmelt, streamflow, water management, water resource, chile1607-7938Streamflow 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.https://www.hydrol-earth-syst-sci.net/22/2921/2018/2921-2935vol.22 is.5Thomson Reuters ISI
Agua y Extremos2018Garreaud, R. D.A plausible atmospheric trigger for the 2017 coastal El Niño: THE 2017 COASTAL EL NIÑOInternational Journal of ClimatologyVer fichael niño, enso, flooding, peru, south america, evaporative cooling systems, oil well flooding, atmospheric circulation, eastern pacific, eastern tropical pacific, enso, evaporative cooling, peru, south america, torrential rain, nickel, coastal zone, el nino, el nino-southern oscillation, flooding, troposphere, westerly, andes, ecuador, pacific ocean, pacific ocean (tropical)0899-8418The 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.http://doi.wiley.com/10.1002/joc.5426Thomson Reuters ISI
Agua y Extremos2018Garreaud, R. D.
Record-breaking climate anomalies lead to severe drought and environmental disruption in western Patagonia in 2016
Climate Research
Ver fichaclimate change, environment, hab, harmful algal bloom, patagonia, sam, southern annular mode0936-577X
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.http://www.int-res.com/abstracts/cr/v74/n3/p217-229/217-229vol.74 is.3Thomson Reuters ISI
Agua y Extremos2018León-Muñoz, J., Urbina, M. A., Garreaud, R., Iriarte, J. L.Hydroclimatic conditions trigger record harmful algal bloom in western Patagonia (summer 2016)Scientific ReportsVer fichaalgal bloom, chile, climate, growth, development and aging, microalga, chile, climate, harmful algal bloom, microalgae2045-2322A 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.http://www.nature.com/articles/s41598-018-19461-4vol.8 is.1Thomson Reuters ISI
Agua y Extremos, Gobernanza e Interfaz entre Ciencia y Política2018Lillo-Ortega, G., Aldunce, P., Adler, C., Vidal, M., Rojas, M.On the evaluation of adaptation practices: a transdisciplinary exploration of drought measures in ChileSustainability Sciencechile, drought, evaluation of adaptation, index for the usefulness of adaptation practices (iupa), resilience, transdisciplinarity1862-4065A 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.http://link.springer.com/10.1007/s11625-018-0619-5Thomson Reuters ISI
Agua y Extremos2018Lucas C., Puchi P., Profumo L., Ferreira A., Muñoz A.Effect of climate on tree growth in the Pampa biome of Southeastern South America: First tree-ring chronologies from UruguayDendrochronologiadendroclimatology, río de la plata basin, scutia buxifolia, uruguay, subtropical dendrochronology, biochronology, biome, climate change, climate conditions, climate effect, clonal growth, dendrochronology, dendroclimatology, el nino-southern oscillation, endogenous growth, growth, rainfall, reconstruction, regional climate, subtropical region, temperature effect, tree ring, woody plant, argentina, pampas, rio de la plata, south america, uruguay, scutia buxifolia1125-7865Tree-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.https://linkinghub.elsevier.com/retrieve/pii/S1125786518300249113-122Vol.52Thomson Reuters ISI
Agua y Extremos2018Moreno, P. I., Vilanova, I., Villa-Martínez, R. P., Francois, J. P.,Modulation of Fire Regimes by Vegetation and Site Type in Southwestern Patagonia Since 13 kaFrontiers in Ecology and Evolutionfire regime, lake sediments, paleoclimate, patagonia, vegetation dynamics2296-701XThe 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.http://journal.frontiersin.org/article/10.3389/fevo.2018.00034/fullvol.6Scopus
Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz entre Ciencia y Política2018Moreno, P. I., Vilanova, I., Villa-Martinez, R., Dunbar, R. B., Mucciarone, D. A., Kaplan, M. R., Garreaud, R., Rojas, M., De Polz-Holz, R., Lambert, F.
Onset and Evolution of Southern Annular Mode-Like Changes at Centennial Timescale
Scientific Reports
Ver ficha2045-2322
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.http://www.nature.com/articles/s41598-018-21836-6vol.8 is.1Thomson Reuters ISI
Agua y Extremos2018Nola, C., Overpeck, J. T., Allen, J. R. M., Anderson, P. M., Betancourt, J. L., Binney, H. A., Brewer, S., Bush, M. B., Chase, B. M., Cheddadi, R., Djamali, M., Dodson, J., Edwards, M. E., Gosling, W. D., Haberle, S., Hotchkiss, S. C., Huntley, B., Ivory, S. J., Kershaw, A. P., Kim, S. Latorre, C., Leydet, M., Lézine, A., Liu, K., Liu, Y., Lozhkin, A. V., McGlone, M. S., Marchant, R. A., Momohara, A., Moreno, P. I., Muller, S., Otto-Bliesner, B. L., Shen, C., Stevenson, J., Takahara, H., Tarasov, P. E., Tipton, J., Vincens, A., Weng, C., Xu, Q., Zheng, Z., Jackson, S.Past and future global transformation of terrestrial ecosystems under climate changeSciencebiodiversity, climate change, ecosystem service, glacial-interglacial cycle, global climate, greenhouse gas, last glacial, terrestrial ecosystem, vegetation cover, article, atmosphere, biodiversity, carbon footprint, climate change, ecosystem, biodiversity, biodiversity, climate change0036-8075Impacts 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.http://www.sciencemag.org/lookup/doi/10.1126/science.aan5360920-923vol.361 is.6405Thomson Reuters ISI
Agua y Extremos; Cambio de Uso de Suelo2018Urrutia-Jalabert, R., González, M. E., González-Reyes, A., Lara, A., Garreaud, R.Climate variability and forest fires in central and south-central ChileEcosphereantarctic oscillation, climate change, el niño–southern oscillation (enso), exotic plantations, forest fires, mediterranean forests, temperate forests2150-8925This 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.
http://doi.wiley.com/10.1002/ecs2.2171e02171vol.9 is.4Thomson Reuters ISI
Agua y Extremos2018Valenzuela, R. A., Kingsmill, D. E.
Terrain-Trapped Airflows and Orographic Rainfall along the Coast of Northern California. Part II: Horizontal and Vertical Structures Observed by a Scanning Doppler RadarMonthly Weather Reviewchannel flows, coastal meteorology, kinematics, orographic effects, precipitation, radars/radar observations, atmospheric movements, channel flow, doppler radar, global positioning system, kinematics, landforms, precipitation (chemical), storms, coastal meteorologies, horizontal gradients, kinematic structures, orographic effects, orographic precipitation, orographic rainfalls, precipitation structure, radars/radar observations, precipitation (meteorology), airflow, coastal zone, hydrometeorology, orographic effect, precipitation assessment, rainfall, terrain, wind direction, california, united states0027-0644This 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.http://journals.ametsoc.org/doi/10.1175/MWR-D-17-0227.12381-2402vol.146 is.8Thomson Reuters ISI
Agua y Extremos2018Viale M., Valenzuela R., Garreaud R.D., Ralph F.M.Impacts of Atmospheric Rivers on Precipitation in Southern South AmericaJournal of Hydrometeorologyextratropical cyclones, precipitation, south america, south pacific ocean, topographic effects, water vapor, atmospheric transport, extratropical cyclone, precipitation (climatology), regional climate, topographic effect, water vapor, pacific ocean, pacific ocean (south), south america1525-755XThis 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.http://journals.ametsoc.org/doi/10.1175/JHM-D-18-0006.11671-1687Vol.19 is.10Thomson Reuters ISI
Agua y Extremos2018Zambrano, M., Guosheng, L., Haddad, Z.Temporal and spatial evaluation of long-term satellite-based precipitation products across the complex topographical and climatic gradients of ChileRemote Sensing and Modeling of the Atmosphere, Oceans, and Interactions VII978-1-5106-2139-8 978-1-5106-2140-4Satellite-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.https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10782/2513645/Temporal-and-spatial-evaluation-of-long-term-satellite-based-precipitation/10.1117/12.2513645.fullNot indexed
Agua y Extremos, Gobernanza e Interfaz Ciencia y Política2018Sapiains, R, Ugarte, A, Aldunce, P.Los significados de la participación para el cambio climático en ChileAmbiente y Desarrollo0716-1476Este artículo analiza los distintos significados del concepto de participación, para avanzar hacia un modelo más inclusivo de gobernanza del cambio climático en Chile. Para ello, se presenta una revisión bibliográfica que discute distintas epistemologías, teorías y definiciones de la participación, con énfasis en las dificultades para su implementación en el contexto chileno. Posteriormente, se revisan los mecanismos de participación ciudadana desplegados en el desarrollo de instrumentos de gobernanza del cambio climático existentes en Chile. Se distinguen tipos de participación utilizados y se identifican experiencias conducidas desde la sociedad civil y la academia. Finalmente, se discuten los alcances y las limitaciones de los modelos de participación implementados y se resalta la importancia de incrementar la influencia de la sociedad civil y de mejorar los mecanismos existentes. Esto se explica por un escenario de cambio climático que posiblemente requerirá una mayor cantidad de actores involucrados en la toma de decisiones, para anticipar posibles divisiones frente al desarrollo de acciones de adaptación o mitigación más radicales, y que al mismo tiempo demandará mayores niveles de responsabilidad, compromiso y acción de la ciudadanía.http://revistas.javeriana.edu.co/index.php/ambienteydesarrollo/article/view/2218943-60Vol.21 is.41Thomson Reuters ESCI
Cambio de Uso de Suelo, Agua y Extremos2018González, M. E., Gómez-González, S., Lara, A., Garreaud, R., Díaz-Hormazabal, I.The 2010-2015 Megadrought and its influence on the fire regime in central and south-central ChileEcospheredrought, fire regimes, fire-prone vegetation, fire-season length2150-8925Forest 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.http://doi.wiley.com/10.1002/ecs2.2300e02300Vol.9 is.8Thomson Reuters ISI
Gobernanza e Interfaz entre Ciencia y Política, Ciudades Resilientes, Agua y Extremos2018Arriagada, R., Aldunce, P., Blanco, G., Ibarra, C., Moraga, P., Nahuelhual, L., O'Ryan, R., Urquiza, A., Gallardo, L.Climate change governance in the Anthropocene: Emergence of Polycentrism in ChileElem Sci Anthchile, climate change, governance, polycentrism, public consultation, action plan, adaptive management, anthropocene, climate change, conceptual framework, decision making, environmental policy, financial system, governance approach, mitigation, strategic approach, chile2325-1026Multilateral efforts are essential to an effective response to climate change, but individual nations define climate action policy by translating local and global objectives into adaptation and mitigation actions. We propose a conceptual framework to explore opportunities for polycentric climate governance, understanding polycentricity as a property that encompasses the potential for coordinating multiple centers of semiautonomous decision-making. We assert that polycentrism engages a diverse array of public and private actors for a more effective approach to reducing the threat of climate change. In this way, polycentrism may provide an appropriate strategy for addressing the many challenges of climate governance in the Anthropocene. We review two Chilean case studies: Chile’s Nationally Determined Contribution on Climate Change and the Chilean National Climate Change Action Plan. Our examination demonstrates that Chile has included a diversity of actors and directed significant financial resources to both processes. The central government coordinated both of these processes, showing the key role of interventions at higher jurisdictional levels in orienting institutional change to improve strategic planning and better address climate change. Both processes also provide some evidence of knowledge co-production, while at the same time remaining primarily driven by state agencies and directed by technical experts. Efforts to overcome governance weaknesses should focus on further strengthening existing practices for climate change responses, establishing new institutions, and promoting decision-making that incorporates diverse social actors and multiple levels of governance. In particular, stronger inclusion of local level actors provides an opportunity to enhance polycentric modes of governance and improve climate change responses. Fully capitalizing on this opportunity requires establishing durable communication channels between different levels of governance.https://www.elementascience.org/article/10.1525/elementa.329/68Vol.6 is.1Thomson Reuters ISI
Agua y Extremos2018Bowman,D., Moreira-Muñoz, A., Kolden, F., Chávez, A., Muñoz, R., Salinas, F., González-Reyes, G., Rocco, N., de la Barrera, F., Williamson, G., Borchers, N., Cifuentes, L., Abatzoglou, F., JohnstonHuman–environmental drivers and impacts of the globally extreme 2017 Chilean firesAmbiofire weather, forest plantations, land cover change, mediterranean climate, smoke pollution, wildfire, atmospheric pollution, extreme event, forest fire, health risk, land cover, mediterranean environment, modis, native species, pollution incidence, satellite altimetry, smoke, chile, eucalyptus, drought, fire, human, pine, weather, droughts, fires, humans, pinus0044-7447In 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.http://link.springer.com/10.1007/s13280-018-1084-1Thomson Reuters ISI
Agua y Extremos2018Yáñez-Morroni, G., Gironás, J., Caneo, M., Delgado, R., Garreaud, R.Using the Weather Research and Forecasting (WRF) Model for Precipitation Forecasting in an Andean Region with Complex TopographyAtmosphereandean watershed, complex topography, flash floods, rainfall, wrf forecast, land use, rain, topography, complex topographies, flash flood, land surface models, meteorological forcing, mountainous terrain, precipitation forecasting, temporal simulation, weather research and forecasting models, weather forecasting, atmospheric modeling, computer simulation, ensemble forecasting, precipitation (climatology), regional climate, temporal analysis, urban atmosphere2073-4433The 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.http://www.mdpi.com/2073-4433/9/8/304304Vol.9 is.8Thomson Reuters ISI
Agua y Extremos2018Barrios, A., Trincado, G., Garreaud, R.Alternative approaches for estimating missing climate data: application to monthly precipitation records in South-Central ChileForest Ecosystemsartificial neural networks, climatological data, cross-validation, multiple linear regression2197-5620Background :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.https://forestecosyst.springeropen.com/articles/10.1186/s40663-018-0147-xVol.5 is.1Thomson Reuters ISI
Agua y Extremos2018Garreaud, R. D.Tres niños sorprendentesBoletín Técnico Instituto de Geofísica del Perú (IGP)http://intranet.igp.gob.pe/sysppr/results/result_71/Boletin_Tecnico_PPR_El_Nino_IGP_201801.pdfVol.5 is.1Not indexed
Agua y Extremos, Cambio de Uso de Suelo2018Alvarez-Garreton, C., Mendoza, P. A., Boisier, J. P., Addor, N., Galleguillos, M., Zambrano-Bigiarini, M., Lara, A., Puelma, C., Cortes, G., Garreaud, R., McPhee, J., Ayala, A.The CAMELS-CL dataset - links to files. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.894885PANGAEA. Data Publisher for Earth & Environmental Sciencehttps://doi.pangaea.de/10.1594/PANGAEA.894885Not indexed
Agua y Extremos, Ciudades Resilientes, Gobernanza e Interfaz entre Ciencia y Política2018Boisier, J.P., Alvarez-Garreton, C., Cordero, R.R., Damiani, A., Gallardo, L., Garreaud, R.D., Lambert, F., Ramallo, C., Rojas, M., Rondanelli, R.Anthropogenic drying in central-southern Chile evidenced by long-term observations and climate model simulationsElementa: Science of the Anthropocenechile, climate change, drought, drying trends, greenhouse gas and ozone depletion, southern annular mode, anthropogenic effect, carbon emission, climate modeling, drought, greenhouse gas, long-term change, ozone depletion, simulation, streamflow, trend analysis, vulnerability, chile2325-1026Since 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.https://www.elementascience.org/article/10.1525/elementa.340/74Vol.6 is.1Thomson Reuters ISI
Agua y Extremos, Ciudades Resilientes, Gobernanza e Interfaz entre Ciencia y Política, Transversal2019Barría, P., Rojas, M., Moraga, P., Muñoz, A., Bozkurt, D., Alvarez-Garreton, C.Anthropocene and streamflow: Long-term perspective of streamflow variability and water rightsElementa: Science of the Anthropocenemulticentury variability, runoff variability, water governance, water rights2325-1026The 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.https://www.elementascience.org/article/10.1525/elementa.328/2Vol.7 is.1Thomson Reuters ISI
Agua y Extremos, Cambio de Uso de Suelo2019Chávez, R.O., Moreira-Munoz, A., Galleguillos, M., Olea, M., Aguayo, J., Latín, A., Aguilera-Betti, I., Muñoz, A. A., Manriquez, H.GIMMS NDVI time series reveal the extent, duration, and intensity of “blooming desert” events in the hyper-arid Atacama Desert, Northern ChileInternational Journal of Applied Earth Observation and Geoinformationephemeral vegetation, extreme events, land surface phenology, npphen, precipitation variability, remote sensing, time series, desert, extreme event, land surface, numerical model, phenology, precipitation intensity, remote sensing, time series, vegetation mapping, atacama desert, chile0303-2434The “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.https://linkinghub.elsevier.com/retrieve/pii/S0303243418306202193-203Vol.76Thomson Reuters ISI
Agua y Extremos; Zonas Costeras; Transversal2019Rondanelli, R.; Hatchett, B.; Rutllant, J.; Bozkurt, D.; Garreaud, R.Strongest MJO on Record Triggers Extreme Atacama Rainfall and Warmth in AntarcticaGeophysical Research Lettersantarctica, atmospheric rivers, climate dynamics, extremes, flooding, rossby waves, flood control, floods, mechanical waves, oil well flooding, rain, tropics, antarctic peninsula, antarctica, atmospheric response, climate dynamics, extremes, madden-julian oscillation, rossby wave, rossby wave response, climatology, air-sea interaction, barotropic wave, climate change, extreme event, flood, flooding, high temperature, rainfall, teleconnection, wave velocity, atacama desert, chile, pacific ocean, pacific ocean (central), pacific ocean (southeast), south america, west antarctica0094-8276Tropical 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.https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081475vol. is.Thomson Reuters ISI
Agua y Extremos; Cambio de Uso de Suelo2019Collins, James A.; Lamy, Frank; Kaiser, Jérôme; Ruggieri, Nicoletta; Henkel, Susann; De Pol‐Holz, Ricardo; Garreaud, René; Arz, Helge W.Centennial‐Scale SE Pacific Sea Surface Temperature Variability Over the Past 2,300 YearsPaleoceanography and Paleoclimatologyclimate change, convection, cooling, el nino-southern oscillation, holocene, medieval warm period, reconstruction, sea ice, sea surface temperature, pacific ocean, pacific ocean (southeast), southern ocean, weddell sea2572-4517Detailed 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.https://onlinelibrary.wiley.com/doi/abs/10.1029/2018PA003465vol. is.Thomson Reuters ISI
Agua y Extremos; Cambio de Uso de Suelo2019Alvarez-Garreton, Camila; Lara, Antonio; Boisier, Juan Pablo; Galleguillos, MauricioThe Impacts of Native Forests and Forest Plantation on Water Supply in ChileForestschile, forest plantation, grassland, land use and land cover change, native forest, ndc, shrubland, water provision, water supply, catchments, decision making, land use, large dataset, reforestation, regression analysis, runoff, chile, forest plantation, grassland, land use and land cover change, native forests, shrublands, water provision, water supply, eucalyptus, pinus radiata1999-4907Over 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.https://www.mdpi.com/1999-4907/10/6/473473vol.10.0 is.6Thomson Reuters ISI
Agua y Extremos2019Moreno, P.I.; Simi, E.; Villa-Martínez, R.P.; Vilanova, I.Early arboreal colonization, postglacial resilience of deciduous Nothofagus forests, and the Southern Westerly Wind influence in central-east Andean PatagoniaQuaternary Science Reviewscharcoal, deforestation, expansion, glacial geology, environmental gradient, invasive exotic species, last glacial maximum, last glacial terminations, natural disturbance regime, nothofagus forests, southern westerly winds, spatial heterogeneity, climate change, biogeography, climate change, climate variation, colonization, deciduous forest, deforestation, deglaciation, disturbance, fossil record, heterogeneity, last glacial maximum, limiting factor, pollen, postglacial, precipitation (climatology), reproduction, vegetation type, andes, patagonia, nothofagus0277-3791The 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.https://linkinghub.elsevier.com/retrieve/pii/S027737911930122261-74vol.218.0 is.Thomson Reuters ISI
Agua y Extremos; Gobernanza e Interfaz Ciencia y Política2019Reynhout, Scott A.; Sagredo, Esteban A.; Kaplan, Michael R.; Aravena, Juan Carlos; Martini, Mateo A.; Moreno, Patricio I.; Rojas, Maisa; Schwartz, Roseanne; Schaefer, Joerg M.Holocene glacier fluctuations in Patagonia are modulated by summer insolation intensity and paced by Southern Annular Mode-like variabilityQuaternary Science Reviewscosmogenic isotopes, geomorphology, glacial, glaciation, holocene, insolation, paleoclimatology, south america, southern annular mode, expansion, geomorphology, glacial geology, cosmogenic isotopes, glacial, glaciation, holocenes, paleoclimatology, south america, southern annular mode, incident solar radiation2773791Alpine 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.https://linkinghub.elsevier.com/retrieve/pii/S0277379119300745178-187vol.220.0 is.Thomson Reuters ISI
Agua y Extremos; Zonas Costeras2019Garreaud, René D.; Boisier, Juan P.; Rondanelli, Roberto; Montecinos, Aldo; Sepúlveda, Hector H.; Veloso‐Aguila, DanielThe Central Chile Mega Drought (2010–2018): A climate dynamics perspectiveInternational Journal of Climatologychile, climate change, drought, enso, pdo, sam, south america, atmospheric pressure, climate change, deforestation, drought, greenhouse gases, mechanical waves, oceanography, ozone layer, rain, tropics, anthropogenic forcing, anticyclonic anomalies, chile, climate model simulations, enso, numerical experiments, south america, stratospheric ozone depletion, climate models0899-8418, 1097-0088Central 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.https://onlinelibrary.wiley.com/doi/abs/10.1002/joc.6219joc.6219vol. is.Thomson Reuters ISI
Agua y Extremos2019Aguayo, Rodrigo; León-Muñoz, Jorge; Vargas-Baecheler, José; Montecinos, Aldo; Garreaud, René; Urbina, Mauricio; Soto, Doris; Iriarte, José LuisThe glass half-empty: climate change drives lower freshwater input in the coastal system of the Chilean Northern PatagoniaClimatic Changeclimate models, digital storage, remote sensing, rivers, stream flow, water, general circulation model, historical records, hydrological modeling, index of agreements, meteorological data, oceanographic conditions, probability of occurrence, streamflow records, climate change0165-0009, 1573-1480Oceanographic 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.http://link.springer.com/10.1007/s10584-019-02495-6vol. is.Thomson Reuters ISI
Agua y Extremos; Ciudades Resilientes; Cambio de Uso de Suelo2019Muñoz, Ariel A.; Klock-Barría, Karin; Sheppard, Paul R.; Aguilera-Betti, Isabella; Toledo-Guerrero, Isadora; Christie, Duncan A.; Gorena, Tamara; Gallardo, Laura; González-Reyes, Álvaro; Lara, Antonio; Lambert, Fabrice; Gayo, Eugenia; Barraza, Francisco; Chávez, Roberto O.Multidecadal environmental pollution in a mega-industrial area in central Chile registered by tree ringsScience of The Total Environmentbaseline, cupressus macrocarpa, dendrochemistry, industrial pollution, trace metals, air quality, aluminum alloys, pollution control, trace elements, trees (mathematics), baseline, dendrochemistry, industrial pollution, macrocarpa, trace metal, forestry, cupressus macrocarpa0048-9697One 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.https://linkinghub.elsevier.com/retrieve/pii/S0048969719338653133915vol.696.0 is.Thomson Reuters ISI
Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Transversal; Zonas Costeras2019Bozkurt, Deniz; Rojas, Maisa; Boisier, Juan Pablo; Rondanelli, Roberto; Garreaud, René; Gallardo, LauraDynamical downscaling over the complex terrain of southwest South America: present climate conditions and added value analysisClimate Dynamicsatacama desert, chile, climate variability, model evaluation, patagonia, temporal-spatial scale analysis0930-7575, 1432-0894This 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.http://link.springer.com/10.1007/s00382-019-04959-yvol. is.Thomson Reuters ISI
Agua y Extremos2019Ramos, Alexandre M.; Wilson, Anna M.; DeFlorio, Michael J.; Warner, Michael D.; Barnes, Elizabeth; Garreaud, Rene; Gorodetskaya, Irina V.; Lavers, David A.; Moore, Benjamin; Payne, Ashley; Smallcomb, Chris; Sodemann, Harald; Wehner, Michael; Ralph, Fred Martin2018 International Atmospheric Rivers Conference: Multi‐disciplinary studies and high‐impact applications of atmospheric riversAtmospheric Science Lettersatmospheric rivers, international atmospheric rivers conference, meeting report1530-261X, 1530-261XAtmospheric 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.https://onlinelibrary.wiley.com/doi/abs/10.1002/asl.935vol.20.0 is.9Thomson Reuters ISI
Agua y Extremos; Ciudades Resilientes2019Gayo, Eugenia M.; McRostie, Virginia B.; Campbell, Roberto; Flores, Carola; Maldonado, Antonio; Uribe-Rodriguez, Mauricio; Moreno, Patricio I.; Santoro, Calogero M.; Christie, Duncan A.; Muñoz, Ariel A.; Gallardo, LauraGeohistorical records of the Anthropocene in ChileElem Sci Anthanthropogenic landscapes, archeological records, historical ecology, niche construction, paleoenvironmental records, socio-ecological systems2325-1026The 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.https://www.elementascience.org/article/10.1525/elementa.353/15.0vol.7.0 is.1Thomson Reuters ISI
Agua y Extremos2019Vilanova, I.; Moreno, P.I.; Miranda, C.G.; Villa-Martínez, R.P.The last glacial termination in the Coyhaique sector of central PatagoniaQuaternary Science Reviewsglacial geology, lakes, reforestation, vegetation, biological productivity, continental landmass, deep water convection, glacial terminations, last glacial maximum, last glacial terminations, southern south america, southern westerly winds, climate change0277-3791https://linkinghub.elsevier.com/retrieve/pii/S0277379119306572105976vol.224.0 is.Thomson Reuters ISI
Agua y Extremos2019Valenzuela, Raúl A.; Garreaud, René D.Extreme Daily Rainfall in Central-Southern Chile and Its Relationship with Low-Level Horizontal Water Vapor FluxesJournal of Hydrometeorology1525-755X, 1525-7541Extreme 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.http://journals.ametsoc.org/doi/10.1175/JHM-D-19-0036.11829-1850vol.20.0 is.9Thomson Reuters ISI
Cambio de Uso de Suelo; Agua y Extremos2019Becerra-Rodas, Constanza; Little, Christian; Lara, Antonio; Sandoval, Jorge; Osorio, Sebastián; Nimptsch, JorgeThe Role of Streamside Native Forests on Dissolved Organic Matter in Forested and Agricultural Watersheds in Northwestern PatagoniaForests1999-4907Streamside 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.https://www.mdpi.com/1999-4907/10/7/595595vol.10.0 is.7Thomson Reuters ISI
Agua y Extremos2019Valenzuela, Raúl A.; Garreaud, René D.Extreme Daily Rainfall in Central-Southern Chile and Its Relationship with Low-Level Horizontal Water Vapor FluxesJournal of Hydrometeorologychile, energy access, energy equity, energy poverty, energy quality, middle-development country, public policy, chile, development countries, energy access, energy equity, energy poverties, energy quality, developing countries1525-755X, 1525-7541Extreme 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.http://journals.ametsoc.org/doi/10.1175/JHM-D-19-0036.11829-1850vol.20.0 is.9Thomson Reuters ISI