Impacto del cambio climático global : estado de situación

Fil: Rusticucci, Matilde. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina.Al detectar el problema del cambio climático mundial, la\nOrganización Meteorológica Mundial (OMM) y el Programa de las\nNaciones Unidas para el Medio Ambiente (PNUMA) crearon el Panel\nIntergubernamental de Expertos sobre el Cambio Climático (IPCC,\npor sus siglas en inglés) en 1988. El IPCC sintetiza en sus informes\nregulares el estado del conocimiento del cambio climático a lo largo\nde la historia, lo que sucede en el presente y hace proyecciones de\nlo que sucederá en el futuro de acuerdo con diferentes escenarios\nposibles que dependen del modo en que interactuarán los diversos\nfactores, naturales y asociados con las actividades humanas, que\ninfluyen en el clima y por lo tanto en el medio ambiente y la vida que\nse desarrolla en la Tierra

Long-lasting floods buffer the thermal regime of the Pampas

This work was funded by grants from the National Research Council of Argentina (CONICET), the International Research Development Centre [IDRC-Canada, Project 106601-001], ANPCyT [PRH 27 [PICT 2013-2973; PICT 2014-2790], and the Inter-American Institute for Global Change Research [IAI, CRN II 2031], which is supported by the US National Science Foundation[Grant number 448 GEO-0452325]. We thank Dr. Horacio Zagarese from INTECH for the lagoon temperature dataset provided. We thank the anonymous reviewers for their careful reading of our manuscript and their many insightful comments and suggestions.Peer reviewedPostprin

Analysis of interdecadal variability of temperature extreme events in Argentina applying EVT

The frequency of occurrence of temperature extreme events has changed throughout the last century: significant positive trends in warm nights and negative trends in cold nights have been observed all over the world. In Argentina, the probability of occurrence of warm annual extremes of maximum temperature has decreased in the last decades, while there has been an increase in warm annual extremes of minimum temperature. The main objective of this paper is to evaluate observed interdecadal changes in the distribution of temperature events that exceed a fixed threshold in five meteorological stations from Argentina over the period 1941-2000, by applying the extreme value theory (EVT). The availability of daily data allows fitting a generalized Pareto distribution (GPD) to daily temperature anomalies over the 90th or below the 10th percentile, in order to estimate return values of extreme events. Daily temperature anomalies are divided into three consecutive and non-overlapping subperiods of 20 years. GPD is fitted to each subperiod independently and a comparison is made between return values estimated in each subperiod. Results show that there is a decrease in the intensity of warm extreme events during the whole period, together with anincrease in its frequency of occurrence during the last 20 years of the twentieth century. Cold extremes alsoshow a decrease in their intensity. However, changes in their frequency of occurrence are not so consistentbetween the different stations analyzed.La frecuencia de ocurrencia de los eventos extremos de temperatura ha sufrido variaciones a lo largo del último siglo: se han observado tendencias positivas significativas en las noches cálidas y tendencias negativas en las noches frías en todo el mundo. En Argentina, la probabilidad de ocurrencia de extremos cálidos anuales de la temperatura máxima disminuyó en las últimas décadas, mientras que hubo un incremento en la probabilidad de ocurrencia de extremos cálidos anuales de la temperatura mínima. El objetivo principal de este trabajo es evaluar la variabilidad interdecadal observada en la distribución de los eventos de temperatura que superan un determinado umbral en cinco estaciones meteorológicas de Argentina durante el periodo 1941-2000, mediante la aplicación de la teoría de valores extremos. La disponibilidad de datos diarios permite el ajuste de la distribución generalizada de Pareto (DGP) a las anomalías diarias de temperatura que exceden el percentil 90 o que no alcanzan el percentil 10 con el propósito de estimar los valores de retorno de los eventos extremos. Las series de anomalías diarias de temperatura se dividen en tres subperiodos consecutivos sin superposición de 20 años cada uno. La DGP se ajusta en cada uno de los tres subperiodos en forma independiente y se comparan los valores de retorno estimados en cada subperiodo. Los resultados muestran que hay una disminución en la intensidad de eventos extremos cálidos durante todo el periodo de estudio, junto con un incremento en su frecuencia de ocurrencia durante los últimos 20 años del siglo XX. Los extremos fríos también muestran una disminución en intensidad. Sin embargo, los cambios en su frecuencia de ocurrencia no son tan consistentes entre las diferentes estaciones estudiadas

Analysis of interdecadal Variability of Temperature Extreme Events in Argentina applying EVT

La frecuencia de ocurrencia de los eventos extremos de temperatura ha sufrido variaciones a lo largo del último siglo: se han observado tendencias positivas significativas en las noches cálidas y tendencias negativas en las noches frías en todo el mundo. En Argentina, la probabilidad de ocurrencia de extremos cálidos anuales de la temperatura máxima disminuyó en las últimas décadas, mientras que hubo un incremento en la probabilidad de ocurrencia de extremos cálidos anuales de la temperatura mínima. El objetivo principal de este trabajo es evaluar la variabilidad interdecadal observada en la distribución de los eventos de temperatura que superan un determinado umbral en cinco estaciones meteorológicas de Argentina durante el periodo 1941-2000, mediante la aplicación de la teoría de valores extremos. La disponibilidad de datos diarios permite el ajuste de la distribución generalizada de Pareto (DGP) a las anomalías diarias de temperatura que exceden el percentil 90 o que no alcanzan el percentil 10 con el propósito de estimar los valores de retorno de los eventos extremos. Las series de anomalías diarias de temperatura se dividen en tres subperiodos consecutivos sin superposición de 20 años cada uno. La DGP se ajusta en cada uno de los tres subperiodos en forma independiente y se comparan los valores de retorno estimados en cada subperiodo. Los resultados muestran que hay una disminución en la intensidad de eventos extremos cálidos durante todo el periodo de estudio, junto con un incremento en su frecuencia de ocurrencia durante los últimos 20 años del siglo XX. Los extremos fríos también muestran una disminución en intensidad. Sin embargo, los cambios en su frecuencia de ocurrencia no son tan consistentes entre las diferentes estaciones estudiadas.The frequency of occurrence of temperature extreme events has changed throughout the last century: significant positive trends in warm nights and negative trends in cold nights have been observed all over the world. In Argentina, the probability of occurrence of warm annual extremes of maximum temperature has decreased in the last decades, while there has been an increase in warm annual extremes of minimum temperature. The main objective of this paper is to evaluate observed interdecadal changes in the distribution of temperature events that exceed a fixed threshold in five meteorological stations from Argentina over the period 1941-2000, by applying the extreme value theory (EVT). The availability of daily data allows fitting a generalized Pareto distribution (GPD) to daily temperature anomalies over the 90th or below the 10th percentile, in order to estimate return values of extreme events. Daily temperature anomalies are divided into three consecutive and non-overlapping subperiods of 20 years. GPD is fitted to each subperiod independently and a comparison is made between return values estimated in each subperiod. Results show that there is a decrease in the intensity of warm extreme events during the whole period, together with an increase in its frequency of occurrence during the last 20 years of the twentieth century. Cold extremes also show a decrease in their intensity. However, changes in their frequency of occurrence are not so consistent between the different stations analyzed.Fil: Tencer, Barbara. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; ArgentinaFil: Rusticucci, Matilde Monica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentin

Multidecadal changes in the relationship between extreme temperature events in Uruguay and the general atmospheric circulation

n/

Climate and Health in Buenos Aires: A Review on Climate Impact on Human Health Studies Between 1995 and 2015

In this review, seven pieces of research on climate variability and its impact on human health in Buenos Aires City between 1995 and 2015 were evaluated. The review highlighted continuities and ruptures in the methodology, variables, and statistics data of the research, considering their similarities and differences in the period of study and the methodology applied. Contributions, pending issues, and public policies on climate change challenges in the city aimed at improving living conditions were considered. Six studies contributed evidence on the relationship between climate and health and its impacts on the population; two studies suggested the development of early warning systems and one study is a preliminary approach.Fil: Fontan, Silvia Graciela. Universidad Nacional de La Matanza; ArgentinaFil: Rusticucci, Matilde Monica. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Variabilidad regional de las temperaturas de superficie en intervalos diarios y cuatridiurnos

Fil:Rusticucci, Matilde. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Warm and cold events in Argentina and their relationship with South Atlantic and South Pacific Sea surface temperatures

A Singular Value Decomposition (SVD) analysis was performed jointly on extreme temperature events in Argentina and sea surface temperature (SST) in the South Atlantic and South Pacific. Sea level pressure (SLP) patterns associated with the first SVD coupled mode were also analyzed. Winter is the season of the year that is best represented by the first mode, accounting for up to 70% of the winter covariance between temperature events and SST. The warm and cold events in Argentina are essentially a consequence of the creation of meridional atmospheric circulations over the continent. Such atmospheric patterns result from displacements and intensity changes of the subtropical anticyclones over the oceans and of the continental low-pressure center in northwestern Argentina. The temperature events in southern Argentina are also closely related to the warming and cooling of the coastal waters in the South Atlantic and South Pacific. The analysis suggests that in summer and winter, high (low) occurrence of warm events and low (high) occurrence of cold events are related to similar oceanic and atmospheric circulation situations. The temperature events in Argentina show higher correlation with the Atlantic than with the Pacific, which reflects the importance of the "orographic barrier" of the Andes Mountains in driving the atmospheric circulation. The only exception to this rule concerns the warm events in spring, for which the warming of the equatorial Pacific (the ENSO pattern) appears as the dominant mode. The temporal patterns of the temperature events in Argentina exhibit significant interannual variability in fall, winter, and spring, with periods of 3 to 5 years. The summer patterns suggest a very low-frequency variation with a period longer than 20 years. Copyright 2003 by the American Geophysical Union.Fil:Rusticucci, M.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Vargas, W.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Summer seasonal predictability of warm days in Argentina: statistical model approach

Predicting extreme temperature events can be very useful for different sectorsthat are strongly affected by their variability. The goal of this study is toanalyze the influence of the main atmospheric, oceanic, and soil moistureforcing on the occurrence of summer warm days and to predict extremetemperatures in Argentina northern of 40°S by fitting a statistical model. In apreliminary analysis, we studied trends and periodicities. Significant positivetrends, fundamentally in western Argentina, and two main periodicities ofsummer warm days were detected: 2?4 years and approximately 8 years.Lagged correlations allowed us to identify the key predictors: ElNiño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), andStandardized Precipitation Indices (SPI). We also noticed that the frequency ofwarm days in spring acts as a good predictor of summer warm days. Due to thecollinearity among many predictors, principal component regression was usedto simulate summer warm days. We obtained negative biases (i.e., the modeltends to underestimate the frequency of summer warm days), but the observedand simulated values of summer warm days were significantly correlated,except in northwest Argentina. Finally, we analyzed the predictability of thesummer warm days under ENSO neutral conditions, and we found newpredictors: the geopotential height gradient in 850 hPa (between the AtlanticAnticyclone and the Chaco Low) and the Atlantic Multidecadal Oscillation(AMO), while the PDO and SPI lost some relevance.Fil: Collazo, Soledad Maribel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; ArgentinaFil: Barrucand, Mariana Graciela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; ArgentinaFil: Rusticucci, Matilde Monica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentin

Atmospheric circulation influence on temperature and precipitation individual and compound daily extreme events: Spatial variability and trends over southern South America

Southern South America (SSA) is an extended region where temperature and precipitation daily extreme events have several impacts on the different socio-economic activities. In this work, their individual and compound occurrence over SSA and their association with atmospheric circulation were studied during 1979–2015, using meteorological stations and the CPC gridded dataset. Results were generally in good agreement between both datasets. The occurrence of a warm night (minimum temperature exceeding the 90th percentile) or a cold day (maximum temperature below the 10th percentile) significantly increases the probability of heavy precipitation (daily precipitation exceeding the 75th percentile) in southern Chile and southeastern South America. These compound events were regionally conditioned by specific circulation types. In addition, both individual and compound extremes showed trends in the different sub-regions. On one hand, heavy precipitation exhibited a significant increase over central-eastern Argentina and Uruguay, northeastern Argentina and southern Brazil during the warm season, and a significant decrease in central and southern Chile during the cold season. On the other hand, warm (cold) extremes generally presented significant upward (downward) trends. Compound events showed significant positive trends for selected regions, in some cases coincident with trends in individual extremes. Changes in the frequency of circulation patterns were found to partly influence some of these trends, like the increases in heavy precipitation and warm extremes during the warm season.Fil: Olmo, Matías Ezequiel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bettolli, Maria Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; ArgentinaFil: Rusticucci, Matilde Monica. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentin