Juan Rivera

National Scientific and Technical Research Council | conicet · IANIGLA - Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales

This study evaluates the performance of precipitation simulated in the historical runs of the Climate Model Intercomparison Project Phase 6 (CMPI6) in capturing the complex spatial and temporal patterns observed over Southwestern South America (SWSA). Precipitation outputs from 14 general circulation models (GCMs) were compared with observations fr...

This study documents the projected changes in several components (precipitation, runoff, snow cover and depth, soil moisture) of the hydrological cycle in Central-Western Argentina (CWA) based on the simulations from the IPSL-CM6A-LR model for the warming levels proposed in the Paris Agreement. These warming levels represent the future increase in...

Most of the water used for the development of the main socio-economic activities in Central-Western Argentina (CWA), an arid to semi-arid region, home to most of the Argentinean wine production, relies on surface streamflow from several snow-fed rivers. During the last decade (2010-2020), reduced snow accumulation over the higher elevations of the...

We evaluate the performance of a large ensemble of Global Climate Models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) over South America for a recent past reference period and examine their projections of twenty-first century precipitation and temperature changes. The future changes are computed for two time slices (2040–20...

Chapter 2 assesses observed large-scale changes in climate system drivers, key climate indicators and principal modes of variability. Chapter 3 considers model performance and detection/attribution, and Chapter 4 covers projections for a subset of these same indicators and modes of variability. Collectively, these chapters provide the basis for lat...

En la cuenca del río Mendoza, la ocurrencia de eventos de precipitaciones intensas en los meses de verano provoca procesos de erosión severa, flujos de derrubios e inundaciones repentinas que modifican la turbiedad del río Mendoza. El exceso de sedimentos arrastrados durante la ocurrencia de estos eventos afecta el trabajo de las plantas potabiliza...

Premise of research. Howvegetation adapts to environmental changes is one of the most important questions in plant science. Temperature and precipitation are considered the main climatic drivers of morphological variations in vegetation. Several studies have demonstrated that leaf morphology varies reliably with increasing latitude, and this is mo...

Esta investigación realiza una cuantificación del déficit en los caudales superficiales de los principales ríos de la región de Cuyo, asociado a la extraordinaria sequía hidrológica registrada desde el año 2010. Estos déficits presentan valores récord en el contexto de los últimos 50 años, en particular durante el año hidrológico 2019/20. Las difer...

Resumen La ocurrencia de eventos de precipitaciones intensas suele generar impactos negativos a nivel socio-económico, en particular en regiones semi-áridas que no suelen estar preparadas para enfrentar este tipo de fenómenos. El área metropolitana del Gran Mendoza no es la excepción, siendo afectada por tormentas convectivas durante los meses cáli...

This Annex describes the fundamental features of the main modes of large-scale climate variability assessed across chapters in the AR6 WGI report. Modes are defined as recurrent space-time structures of variability of the climate system with intrinsic spatial patterns, seasonality and timescales. They can arise through the dynamical characteristics...

A monsoon refers to a seasonal transition of regimes in atmospheric circulation and precipitation in response to the annual cycle of solar insolation and the distribution of moist static energy (Wang and Ding, 2008; Wang et al., 2014; Biasutti et al., 2018). A global monsoon can be objectively identified based on precipitation contrasts in the sols...

En el presente capítulo se comparan desde el punto de vista hidroclimático, político y social, tres de las mayores sequías producidas en Mendoza en los últimos 120 años (1924/25; 1968/69 y 2010/15; 2017/19). De esta manera, se exploran los procesos a través de los cuales, la escasez y la carencia son construidas discursiva y políticamente a lo larg...

This paper provides a perspective based on the evaluation of scientific evidence of hail suppression activities in Mendoza, Argentina. The province of Mendoza was home to several cloud-seeding projects over the years intended to prevent hail damage to agriculture. Those projects were motivated by the paramount importance of wine production for the...

Low streamflows caused by natural and anthropogenic forcings affect ecosystems and societies, especially on large timescales. We analysed the main basins of central-north Argentina (CNA) using centennial streamflow data. This study is focussed on describing spatial and temporal variability of hydrological drought events, and evaluating the atmosphe...

This study assesses the possibility of using Global Navigation Satellite System (GNSS) observations in combination with measurements of surface pressure and temperature to derive Integrated Water Vapor (IWVGNSS) estimates in Central-Western Argentina (CWA), a semi-arid region with complex topography. A significant agreement (coefficient of determin...

The prominent Andes cordillera induces significant differences in climates between its eastern and western slopes. These climatic differences are largely reflected by contrasting vegetation and ice coverages but remain poorly documented. This study quantifies the abrupt changes of precipitation and cloud properties at both sides of the Andes south...

The Climate Hazards group Infrared Precipitation with Stations (CHIRPS) dataset was conceived as a tool for monitoring drought and environmental change over land. Recent validation efforts along South America have assessed its suitability for reproducing the main spatial and temporal features of precipitation. Nevertheless, little has been done reg...

Among glacier instabilities, collapses of large parts of low-angle glaciers are a striking, exceptional phenomenon. So far, merely the 2002 collapse of Kolka Glacier in the Caucasus Mountains and the 2016 twin detachments of the Aru glaciers in western Tibet have been well documented. Here we report on the previously unnoticed collapse of an unname...

This paper provides an early career researchers (ECRs) perspective on major challenges and opportunities that arise in the study and understanding of, and the provision of regional information for Climate, Weather and Hydrological (CWH) extreme events. This perspective emerged from the discussions of the early career 3-day Young Earth System Scient...

En la primera etapa de la implementación del Sistema Nacional de Monitoreo y Evaluación de la Degradación de Tierras y Desertificación a nivel local se seleccionaron y consensuaron un conjunto mínimo de indicadores que proporcionan información para describir el estado o la calidad del ambiente en los Sitios Piloto y para determinar la línea de base...

El índice de caudal estandarizado (ICE) se desarrolló siguiendo los lineamientos teóricos del índice de precipitación estandarizado (IPE) para el monitoreo y la comparación de patrones espaciales y temporales de las condiciones hidrológicas considerando como variable de entrada los caudales mensuales. Un paso fundamental para su cálculo consiste en...

En un contexto de cambio climático, donde la influencia del incremento en la temperatura genera una aceleración en el ciclo hidrológico global, se espera que los eventos hidroclimáticos extremos sean más frecuentes y con impactos significativos en la economía y la sociedad. Este trabajo propone mejorar el conocimiento de la variabilidad hidrológica...

Los humedales conforman hábitats donde el agua cumple un rol fundamental en la estructura de los ecosistemas y en la dinámica de las poblaciones. En el sur de Mendoza (Argentina), la Laguna de Llancanelo constituye un sitio Ramsar de importancia a nivel continental que alberga una gran diversidad de aves, destacándose por su abundancia el Flamenco...

Los humedales conforman hábitats donde el agua cumple un rol fundamental en la estructura de los ecosistemas y en la dinámica de las poblaciones. En el sur de Mendoza (Argentina), la Laguna de Llancanelo constituye un sitio Ramsar de importancia a nivel continental que alberga una gran diversidad de aves, destacándose por su abundancia el Flamenco...

Among glacier instabilities, collapses of large parts of low-angle glaciers are a striking, exceptional phenomenon. So far, merely the 2002 collapse of Kolka Glacier in the Caucasus Mountains and the 2016 twin detachments of the Aru glaciers in western Tibet have been well documented. Here we report on the previously unnoticed collapse of an unname...

This paper performed a streamflow drought climatology considering some of the most important rivers of Southern South America, a region highly vulnerable to climatic variations, based on the analysis of monthly streamflow records. The standardized hydrological drought index (SHDI) was used in order to depict the main characteristics of droughts—num...

A validation covering a 30-year period (1987–2016) of the relatively new CHIRPS precipitation dataset was performed over the Central Andes of Argentina (CAA), a semi-arid region with complex topography and sparse ground observations. Precipitation data from 57 rain gauges and several well-known continuous and categorical validation statistics were...

During the period 2010–2015, the semi-arid Central Andes in Argentina (CAA) experienced one of the most severe and long-lasting hydrological droughts on record. Since the snowmelt is the most important source of water, the reduced snowfall over the mountains propagated the drought signal through the streamflows in the adjacent foothills east of the...

The Southern Annular Mode (SAM), also known as the Antarctic Oscillation (AAO), describes the north–south movement of the westerly wind belt that circles Antarctica, dominating the middle to higher latitudes of the Southern Hemisphere. The changing position of the westerly wind belt influences the strength and position of cold fronts and mid-latitu...

The importance of forecasting extreme wet and dry conditions from weeks to months in advance relies on the need to prevent considerable socio-economic losses, mainly in regions of large populations and where agriculture is a key value for the economies, such as Southern South America (SSA). To improve the understanding of the performance and uncert...

A streamflow drought climatology was developed over the Central Andes of Argentina, a semi-arid region highly vulnerable to climatic variations, based on the analysis of daily historical streamflow records. A threshold level approach was applied on a daily basis for three different severity levels, in order to depict the main characteristics of dro...

The importance of forecasting extreme wet and dry conditions from weeks to months in advance relies on the need to prevent considerable socio-economic losses, mainly in regions of large populations and where agriculture is a key value for the economies, like Southern South America (SSA). Therefore, to improve the understanding of the performance an...

In the Central Andes of Argentina (CAA, located between 28° and 38°S), an arid to semi-arid region, irrigation and a variety of socio-economical activities are highly dependent on river streamflows. Permanent and semi-permanent rivers originate mainly from snowmelt and glacier ablation, enabling the development of large agricultural oasis and the c...

Con el propósito de mejorar el conocimiento de la variabilidad temporal de los caudales de los ríos del centro-norte de Argentina en términos de la variabilidad de baja frecuencia, se analizaron los registros mensuales históricos de 10 estaciones de aforo durante el período 1919-2014. A fin de comparar los registros hidrológicos en cuencas con dist...

Under the current global warming trend, droughts are expected to increase, with serious implications for water resources management. This study analyzed the regional aspects of droughts in terms of streamflow deficiencies over the Andean rivers of Patagonia, Argentina. Based on the variable threshold level method, the main characteristics of stream...

In the Central Andes of Argentina (30°–37°S), snowmelt is the main source of freshwater, an essential natural resource for ~2.2 million people in the adjacent arid lowlands. In this region, Laguna Llancanelo collects the water inputs from the Malargüe endorheic basin. Previous studies concerning the annual and intra-annual variations of this lagoon...

The ENSO phenomenon is one of the key factors that influence the interannual variability of precipitation over Southern South America. The aim of this study is to identify the regional response of precipitation to El Niño/La Niña events, with emphasis in drought conditions. The standardized precipitation index (SPI) was used to characterize precipi...

Extreme climate events over the La Plata basin (LPB) can produce significant impacts due to the importance of its agriculture and hydroelectric power production for the local economy. Progresses on describing, projecting and understanding extremes in LPB, in the framework of the CLARIS-LPB Europe-South America Network for Climate Change Assessment...

Existen numerosos índices de sequía que deben ser monitoreados continuamente a fin de determinar el inicio y fin de los eventos de sequía y sus características espacio-temporales. Este trabajo describe y compara el desempeño de seis índices basados en datos de precipitación para el monitoreo de sequías en el sur de Sudamérica, con el objetivo de ob...

The interaction between land surface and atmosphere plays an important role in the climate system. Soil-atmosphere feedback mechanisms are analyzed through calculating the hydric condition (HC) of the soil from the water balance. Spatial coherence between HC and the Standardized Precipitation Index (SPI) as well as the circulation patterns associat...

En este trabajo se estudian los principales modos de variabilidad intra-estacional de escurrimientos superficiales del Río Atuel, provincia de Mendoza, mediante el análisis de componentes principales aplicado a su ciclo hidrológico anual y su relación con la variabilidad local de la precipitación y la temperatura en la región de la cuenca y la circ...

Droughts are perceived as one of the costliest and least understood natural disasters, given the difficulty in defining its beginning and end, its slow development and its multiple regional aspects. Southern South America (SSA) was no exception to this hazard, whose impacts were evident in the reduction in crop yields, reduced cattle products, stre...

This article addresses the regional impacts of climate change on precipitation and meteorological drought over Southern South America (SSA) through a CMIP5 multi-model ensemble based on 15 General Circulation Models (GCMs) forced under two different greenhouse gas concentration pathways (RCP4.5 and RCP8.5). An assessment of the biases in the repres...

RESUMEN: En este trabajo se estudian los principales modos de variabilidad intra-estacional de escurrimientos superficiales del Río Atuel, provincia de Mendoza, mediante el análisis de componentes principales aplicado a su ciclo hidrológico anual; y su relación con la variabilidad local de la precipitación y la temperatura en la región de la cuenca...

RESUMEN: Se identifican los modos principales de variabilidad del ciclo hidrológico anual del Río Chubut y las condiciones atmosféricas responsables de las variaciones interanuales a intra-estacionales de sus caudales. Las primeras cuatro componentes de variabilidad explican alrededor del 33, 23, 15 y 10% de la varianza total. El primer patrón (PC1...

RESUMEN: En el presente trabajo se estimó la evolución temporal de la superficie de la laguna de Llancanelo, ubicada al sur de la provincia de Mendoza, a partir del uso de imágenes satelitales Landsat. En función de la comparación de esta serie temporal con las fluctuaciones de los caudales y las precipitaciones en diversas escalas temporales se ob...

RESUMEN: En el presente trabajo se realiza una comparación del período de crisis hídrica 2010-2014 en la región de Cuyo con otros períodos deficitarios históricos, en función del análisis de su duración y severidad. Se obtuvo que el período seco reciente es el más importante de los últimos 40 años en todas las cuencas analizadas. En algunas de esta...

RESUMEN: El cálculo de amenaza de sequías es una aplicación útil que puede estimarse a través del índice de precipitación estandarizado en distintas escalas temporales. La distribución espacial de los valores de amenaza posee implicancias socio-económicas y puede permitir el desarrollo de mapas de riesgo asociado a las sequías meteorológicas en la...

This study aims to compare simulated soil moisture anomalies derived from different versions of the Global Land Data Assimilation System (GLDAS), the standardized precipitation index (SPI), and a new multisatellite surface soil moisture product over southern South America. The main motivation is the need for assessing the reliability of GLDAS varia...

The aim of this study is to identify support tools for the regional monitoring of drought conditions over Southern South America (SSA). The Standardized Precipitation Index (SPI) was used to characterize rainfall variabilities through the 1961–2008 period. The SPI was calculated at two time scales (3 and 12 months), which represents short-and long-...

Monthly and daily precipitation extremes over La Plata Basin (LPB) are analyzed in the framework of the CLARIS-LPB Project. A review of the studies developed during the project and results of additional research are presented and discussed. Specific aspects of analysis are focused on large-scale versus local processes impacts on the intensity and f...

La interacción entre el suelo, la vegetación y la atmósfera juega un papel importante en el sistema climático. La humedad y la condición hídrica del suelo se determinan por la temperatura y la precipitación a nivel local. La precipitación recarga directamente la humedad del suelo y el ciclo se completa a través de la evapotranspiración, que produce...

Based on 56 rainfall stations, which cover the period 1961–2008, we analyzed the presence of trends in the drought-affected area over southern South America (SSA) at different time scales. In order to define drought conditions, we used the standardized precipitation index, which was calculated on time scales of 1, 3, 6, 9 and 12 months. The trends...

CLARIS LPB database was built within the framework of the CLARIS LPB project “A Europe-South America Network for climate Change Assessment and Impact Studies in La Plata Basin” of the European Community’s Seventh Framework Programme (FP7). The main variables available in the database are rainfall, temperature, radiation, heliophany and streamflow c...

El incremento en la demanda de los recursos hídricos superficiales exige una mejor estimación de las características de las sequías hidrológicas. Uno de los parámetros de interés para el análisis de las deficiencias en los caudales es la cantidad anual de días con caudales bajos, y su variabilidad temporal asociada. Los días con caudales bajos –de...

The impact of climate change on drought main characteristics was assessed over Southern South America. This was done through the precipitation outputs from a multi-model ensemble of 15 climate models of the Coupled Model Intercomparison Project Phase 5 (CMIP5). The Standardized Precipitation Index was used as a drought indicator, given its temporal...

This work proposes to employ the number of dry days (days without precipitation) as a variable of study, and to analyse their spatial and temporal variability in Argentina. Climatological aspects of dry days, such as their annual mean values and its seasonal cycle, were discussed and compared with precipitation features in the country. Linear trend...

El objetivo principal de este trabajo es identificar la época de inicio y fin de la estación lluviosa en la Argentina al norte de 30ºS mediante un índice adecuado y analizar su variabilidad interanual en regiones homogéneas respecto a la variabilidad temporal de la precipitación. Se utilizaron datos de precipitación diaria en 19 estaciones pluviomé...

El Índice de Precipitación Estandarizado (IPE) es uno de los índices de sequía más utilizados a nivel mundial. Este índice se estima en base al ajuste de la distribución gamma a las frecuencias de precipitaciones mensuales para cada localidad, y posteriormente realiza una transformación a fin de estandarizar el índice. Los cambios temporales en los...

El primer paso en el cálculo del Índice de Precipitación Estandarizado es determinar la función de densidad de probabilidad que describe las observaciones de precipitación. Dada la gran variedad de regímenes de precipitación presentes en el Sudeste de Sudamérica (SESA), se analizó qué tan flexible es la distribución de probabilidades gamma para rep...

Due to the increasing demand on surface water resources, it is necessary an assessment of the rainfall deficit conditions. Particularly, northeastern Argentina is part of the La Plata Basin, environment of great economic and demographic significance, and the impacts of droughts on hydrology and agriculture are immediate. The main goal of this resea...

The aim of this research is to validate the spatio-temporal variability of droughts in Southern South America (south of 20°S) depicted by the VAMOS atlas of extremes, trough the Standardized Precipitation Index (SPI). In the study region, droughts are a recurring climatic phenomenon, with periodicities that vary regionally. Monitoring of these extr...

Extreme precipitation (wet or dry) over La Plata Basin (LPB) can cause intense damage in several sectors as agriculture and hydroelectricity, and also has an impact on urban areas due to flooding and landslides. Extreme temperatures (cold incursions or heat waves) have impact on agriculture and health. The frequency and intensity of extremes can va...