Efecto de la ciudad y el rio sobre la temperatura de superficie en Buenos Aires

El objetivo de este trabajo es estudiar algunas estructuras climáticas de la temperatura y las perturbaciones provocadas por la ubicación de las estaciones. Se toman tres estaciones en las inmediaciones y dentro de la ciudad de Buenos Aires. y se analizan las temperaturas de las horas 02:00, 08:00, 14:00 y 20:00. Se muestra que la influencia de la dirección del viento en la manifestación de los efectos de la ciudad o el río en la temperatura, depende de la hora y de la época del año. Sin embargo la estación de referencia no está influenciada por la ciudad, en la mayoría de las veces. El efecto de la ciudad sobre los promedios de temperatura, es máximo en horas de la noche. La influyencia del río, en cambio, es más notable a las 14:00. Ambos efectos se reflejan sobre la distribución de las anomalías de las estaciones estudiadas. Los procesos que dominan estas series son más homogéneos entre estaciones, si se consideran las temperaturas diarias.The alm of this paper is to study the effect of the station location on the six-hourly temperatures climatic structures. The observed temperature (at 02:00. 08:00, 14:00, 20:00, local time), for three stations within the metropolitan area of Buenos Aires, is studied. Local influences depend on the day time and the season. In the analysis of the wind direction, in most oí the situations the reference station is not influenced by the city. The urban effect is maximum al night hours and the river influence is maximum at 14:00. Both effects are still present in the anomalies frequency distribution. The daily anomalies processes are more homogeneous than the six-hourly ones between stations.Asociación Argentina de Geofísicos y Geodesta

Propiedades y procesos dominantes de una serie cuatridiurna de temperatura

Se estudia la serie de temperaturas cuatridiurnas (hora 02, 08 14 y 20), de la estación Ezeiza (34° 49'S, 59° 32'W) en el período 1968-1980, con el objetivo final de obtener un diagnóstico que pueda servir a posteriori para el ajuste de un modelo de pronóstico para la serie. Se investiga el grado de variabilidad o contribución a la serie que introducen los meses, las horas y los años. Los procesos estadísticos dominantes en las series, sean estas cuatridiurnas o diarias, son esencialmente Markovianos, según lo detecta la estimación de las funciones de autocorrelación y espectros de poder. Como se postula que la serie filtrada cuatridiurna puede describirse mediante un mismo proceso, se estudia el espectro hora a hora con el objeto de medir la homogeneidad. Se encuentra que las causas de inhomogeneidad serían provocadas por ondas mayores que 14 días. En función de todas las propiedades que la serie presenta, es factible suponer que un modelo autorregresivo puede ser ajustado con fines de diagnóstico y pronóstico.The series of quartan temperatures of the station Ezeiza (34° 49'S, 59° 32'W) in the period 1968-1980 is being studied, with the final aim to obtain a diagnostic model for the series. The degree of variability or contribution to the series introduced by months, hours and years is being investigated. The statistic processes dominant in the series, be these quartan or daily, are essentially Markovian, according is being revealed by the estimation of the functions of autocorrelation and power spectra. As it is being postulated that the filtered quartan series can be described by means of the same process, the spectrum is being studied hour by hour with the aim to measure homogeneity. It is found that the un-homogeneity is caused by waves longer than a fortnigth. Based on the properties of the series, it is possible to assume that an autorregressive model can be adjusted for diagnostic and forecasting purposes.Asociación Argentina de Geofísicos y Geodesta

Predictibilidad estacional de los extremos de temperatura en Argentina a partir de la circulación atmosférica de gran escala

Las variaciones en la temperatura de la superficie del mar (SST), en particular del Océano Atlántico y Pacifico, tienen influencia sobre el sistema climático provocando cambios en los patrones de circulación atmosférica. El Niño – Oscilación del Sur (ENSO), es el mayor modo de variabilidad en el Pacifico Tropical, causando variaciones interanuales en el clima de todo el mundo. Sin embargo, existen otros modos de variabilidad que también son importantes ya que influyen sobre la temperatura y precipitación de Sudamérica. En el presente trabajo se analizó la habilidad para predecir extremos de temperatura en la Argentina al norte de 40°S de los siguientes modos de variabilidad climáticos: Modo anular del Sur (SAM), Dipolo del Océano Indico (IOD), Oscilación Decadal del Pacífico (PDO) y la Oscilación Multidecádica del Atlántico (AMO). Para ello, se calcularon y testearon estadísticamente las correlaciones desfasadas entre cada uno de los modos climáticos y distintos índices representativos de los extremos de temperatura promediados trimestralmente en el periodo 1970-2015. Estos índices de extremos de temperatura, globalmente utilizados, son: noches frías (TN10), noches cálidas (TN90), días fríos (TX10), días cálidos (TX90) y el número de días con heladas (NDH).Eje: Ciencias de la Atmósfera y los Océanos.Facultad de Ciencias Astronómicas y Geofísica

Variabilidad cada seis horas de la temperatura de superficie

En este trabajo se estudia el comportamiento del cambio de la temperatura cada seis horas en una estación ubicada en la periferia de la ciudad de Buenos Aires. Ese cambio se representa con la "diferencia" de temperatura en seis horas. Se observa mayor cantidad de calentamientos que de enfriamientos pero de menor intensidad. Todas las distribuciones presentan una leve asimetría. Estas "diferencias" pertenecen a ondas de período muy corto, lo que muestra que estos procesos se debilitan rápidamente. En el análisis de valores extremos absolutos, se nota que su ocurrencia tiene horas preferenciales, a pesar de estar filtradas las ondas astronómicas. Es en el intervalo entre las 08 y las 14 donde se producen los mayores calentamientos y enfriamientos.The behavior of the temperature change each six hours, in a station near the city of Buenos Aires is studied. This change is explained by the difference between 6-hourly temporatures. The distributions are slightly assimetric because there are more heatings than coolings but less intense. It can be seen that those "differences" belong to short waves. They show that the processes weaken quickly. A preferent interval occured in the absolute extrem values analysis, in spite of the astronomics waves have been filtered. The mayor heatings and coolings are produced between 08:00 and 14:00.Asociación Argentina de Geofísicos y Geodesta

Rumo a um Observatório Latino-Americano do Clima e da Saúde: Seminário sobre Instrumentos e Metodologias

The study of the relationship between health and climate requires articulating various actors and disciplines. This paper presents the experience of the Latin American Seminar on Instruments and Methodologies for a climate and health observatory— held in Buenos Aires in 2019 and supported by the Latin American Center for Interdisciplinary Training (CELFI)—as a linking and training facility referencing the projects that are being carried out in this field throughout Latin American. This paper presents the design, contents, didactic approach and execution of the seminar, as well as its results regarding participation, products and evaluation. Likewise, the methodologies that could allow articulating different disciplines in a process of gainingknowledge about the climate-health relationship are reflected throughout this process. Finally, the main guidelines for this observatory, arising from an exchange with key actors, are set forth herein. The execution of the seminar, the projects presented as the products thereof, the discussions that arose during the exchange, and the need to continue with this work over the following months point out to the importance and necessity of building this observatory for Latin America and the Caribbean in an interdisciplinary way.El estudio de la relación entre clima y salud requiere la articulación de diversos actores y disciplinas. En este artículo se presenta la experiencia del Seminario Latinoamericano Instrumentos y Metodologías para un observatorio de clima y salud, realizado en Buenos Aires en 2019, apoyado por el Centro Latinoamericano de Formación Interdisciplinaria (CELFI), como un espacio de vinculación, capacitación y referencia a experiencias que se vienen desarrollando en este campo en América Latina. En este trabajo se presenta el diseño del seminario, su contenido, didáctica y desarrollo, así como los resultados en cuanto a participación, productos y evaluación. Asimismo, durante el proceso se reflexiona en torno a las metodologías que permitan articular diferentes disciplinas en un proceso de construcción de conocimiento sobre la relación clima-salud. Finalmente, se explicitan los principales lineamientos del observatorio, surgidos de una instancia de intercambio con actores clave. El desarrollo del seminario, los proyectos presentados como producto, las discusiones surgidas durante el intercambio y la continuidad de trabajo en los meses posteriores permiten dar cuenta de la importancia y necesidad de construir interdisciplinariamente este observatorio para América Latina y el Caribe.O estudo da relação entre o clima e a saúde requere a articulação de diversos atores e disciplinas. Neste artigo, apresenta-se a experiência do Seminário Latino-americano Instrumentos e Metodologias para um observatório de clima e saúde, realizado em Buenos Aires em 2019. Foi apoiado pelo Centro Latino-americano de Formação Interdisciplinar (CELFI), como espaço de vinculação, capacitação e referência das experiências que se estão a desenvolver neste campo na América Latina. Neste trabalho, apresenta- se a conceção do seminário, o seu conteúdo, dinâmica e desenvolvimento, bem como, os resultados em termos de participação, produtos e avaliação. Da mesma forma, durante o processo, é feita uma reflexão sobre as metodologias que permitem a articulação de diferentes disciplinas, num processo de construção do conhecimento sobre a relação clima-saúde. Por fim, explicitam-se as principais diretrizes do observatório, decorrentes de uma plataforma de intercâmbio dos atores chave. O desenvolvimento do seminário, os projetos apresentados como produto, as discussões ocorridas durante o intercâmbio e a continuidade de trabalho nos meses seguintes, permitem perceber a importância e a necessidade de construir este observatório interdisciplinar, para a América Latina e Caribe

Precipitation from persistent extremes is increasing in most regions and globally

Extreme precipitation often persists for multiple days with variable duration but has usually been examined at fixed duration. Here we show that considering extreme persistent precipitation by complete event with variable duration, rather than a fixed temporal period, is a necessary metric to account for the complexity of changing precipitation. Observed global mean annual-maximum precipitation is significantly stronger (49.5%) for persistent extremes than daily extremes. However, both globally observed and modeled rates of relative increases are lower for persistent extremes compared to daily extremes, especially for Southern Hemisphere and large regions in the 0-45°N latitude band. Climate models also show significant differences in the magnitude and partly even the sign of local mean changes between daily and persistent extremes in global warming projections. Changes in extreme precipitation therefore are more complex than previously reported, and extreme precipitation events with varying duration should be taken into account for future climate change assessments

Variability and trends in indices of quality-controlled daily temperature extremes in Uruguay

A database of daily extreme temperature was created for as many stations as possible for Uruguay, as far back as possible. This is the first attempt to gather all the different data sources together, perform a quality control and homogeneity assessment. We work with seven stations; it should be taken into account that Uruguay is a small country (around 177 000 km2) and this represents most of the available data. There are three old series with starting dates in 1930, and four that start around 1950. From this database, a set of four extreme temperature indices was constructed for the oldest five stations, warm days (TX90), cold days (TX10), warm nights (TN90) and cold nights (TN10). The index TN10 shows the largest significant negative trend for the period 1960-2002, while TN90 shows a positive but not significant trend for this period indicating a strong warming of nighttime temperature. A spectral analysis was performed using the multi taper methods (MTM) to the de-trended annual, summer Dec-Feb (DJF) and winter Jun-Aug (JJA) indices time-series. This analysis shows that on inter-annual timescales, the most significant range of frequencies is from 2 to 2.5 years and from 3 to 6 years. Low frequencies of variability were detected when the MTM was applied to de-trended smoothed annual time-series, around the range of frequencies of 15-25 years for almost all the indices analysed. Links with global sea surface temperature (SST) were studied for two stations (Paysandu and Rocha), and it was found that the indices showed largest correlations with SST anomalies in the Pacific Ocean. We detected changes in the response of the TN10 index for Rocha station when the series was split up into two different periods (1942-1976 and 1977-2005). Copyright © 2007 Royal Meteorological Society.Fil:Rusticucci, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Renom, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Temperature extremes in the south of South America in relation to Atlantic Ocean surface temperature and Southern Hemisphere circulation

The objective of this research is to study the main variability modes of the frequency of extreme temperatures in the south of South Amenica, their relation to sea surface temperatures (SSTs), and some indices of atmospheric circulation in the Southern Hemisphere. Observational data and reanalysis data were used for this purpose over the 1964-2003 period. An initial analysis showed that between the months of March and June, the frequency of wann events (especially warm nights) is highly associated with the SST in coastal zones. A wavelet analysis showed that the main variability mode found at a seasonal scale was an 8-year wave signal present in spning that remains active until the 1990s; it was noticeable in the analysis of cold nights, Atlantic SSTs, Pacific SSTs, and the Southern Annular Mode (SAM). A cross-wavelet analysis among them reflected this signal as a common variability mode, with the positive phase of the SAM congruent with the warmest conditions in the coastal zones of the Atlantic Ocean and lower cases with cold nights at the reference meteorological stations analyzed. Although longer series are desirable for low-frequency variability analysis, the results agree with previous studies that take into account an 8-year periodicity of the baroclinic waves at the Southern Hemisphere, supporting the relevance of the 8-year signal. Copyright 2008 by the American Geophysical Union.Fil:Barrucand, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Rusticucci, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Vargas, W. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina