995 resultados para Atmospheric systems
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Seasonal relationship between the Southern Annular Mode (SAM) and the spatial distribution of the cyclone systems over Southern Hemisphere is investigated for the period 1980 to 1999. In addition, seasonal frontogenesis and rainfall distribution over South America and South Atlantic Ocean during different SAM phases were also analyzed. It is observed that during negative SAM phases the cyclone trajectories move northward when compared to the positive one, and in the South America and South Atlantic sector there is intense frontogenetic activity and positive anomaly precipitation over the Southeast of the South America. In general, SAM positive phase shows opposite signals.
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Como a América do Sul se estende por diferentes latitudes e possui formas de relevo variadas, proporciona a atuação e o desenvolvimento de diferentes sistemas atmosféricos, os quais contribuem para a não homogeneidade climática da região. Portanto o objetivo deste estudo é apresentar uma revisão dos sistemas atmosféricos que atuam nos diferentes setores do continente sul-americano e que contribuem para a precipitação.
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Este trabalho tem como objetivo identificar a influência atmosférica em escala sinótica sobre o oceano, para eventos extremos de maré meteorológica na costa sudeste brasileira. Para isso foram utilizados dados de elevação do nível do mar do Porto de Santos-SP, campos de vento e pressão em superfície das reanálises do modelo do NCEP abrangendo o Atlântico Sul, no período de 1951 a 1990. Foi possível identificar a variabilidade sazonal e o padrão de evolução dos sistemas atmosféricos associados aos eventos extremos, de grande relevância para aplicações em prognósticos e alertas a autoridades. O outono e inverno apresentaram a maior ocorrência de extremos positivos (40,2 % e 30,8 % respectivamente), enquanto a primavera e o inverno foram as estações com maior número de extremos negativos (47,2 % e 32,3 % respectivamente). Os resultados mostram que os casos mais importantes de sobre-elevação do nível do mar ocorrem com a evolução e persistência de sistemas de baixa pressão sobre o oceano, com ventos de sudoeste acima de 8 m/s, juntamente com o anticiclone da retaguarda posicionado sobre o continente.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The Urbanization is a notable process in our society, being part of it since around 3500 BC in Mesopotamia, currently Iraq area. Since the Industrial Revolution, cities had a significant increase in their growth and began to concentrate increasingly labor and capital. Brazil, despite having had a late industrialization, also had a high population growth in cities, especially in the XVIII century, which were not provided with any kind of planning that targets the ordering and implementation of the urban essential apparatus. Therefore, Brazilian cities started to exhibit countless structural and environmental problems. Associated with inadequate infrastructure, the modifications in the urban atmosphere, like increased heat, air pollution and increased rainfall and storm frequency, cause different types of impacts in cities. Among the most worrisome are those from the intense rain, which cause human and material damage. The city of Rio Claro (SP) can be considered an example of this reality. Thereby, the objective of this study was to analyze the impacts on the population originated from rainfall in the urban area during the period 2005-2010, by the mapping of events and analysis of the active atmospheric systems. The information of the events were collected in the Fire Department and the Press and the synoptic maps were obtained in the library of INPE, in Cachoeira Paulista (SP) and in the site of the Navy of Brazil. The data showed that among 247 occurrences, during the six years, 233 occurred in the spring-summer period. Moreover, after finalizing the maps, it was found the locations considered critical regarding the frequency of occurrences, as: Visconde do Rio Claro Avenue and central area of the city, both with a total of 23 occurrences; Jardim Inocoop, with 20; Tancredo Neves Avenue, with 12 and Vila Paulista, with 10 occurrences. Through the graphs, it was found that the most recurrent atmospheric system, during the studied period, is...
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This monograph aims to contribute to the understanding and analysis of extreme events and its correlation with anthropogenic actions, in order to understand the levels of human interference in the environment and to identify potential social and environmental damage that such events may result in Ubatuba, located on the northern coast of São Paulo state. Therefore, two strategies were established, on one hand, episodic analysis of extreme weather events, and on the other, the analysis of the impact of atmospheric phenomena in everyday society. In this case we gave greater emphasis to analysis years that had higher total rainfall. In this sense, the research was based on the standard deviation technique and percentages, which supported to characterize the exceptional rainy years, in addition, use of rhythm analysis technique that has helped to identify the active atmospheric systems. From a qualitative point of view, field works were carried out in order to make use of news by the local press and civil defense for years considered extreme (positive standard deviation). From this, it was analyzed how the extreme episodes of rainfall trigger repercussions in geographic space. Also the spatial distribution of rainfall were carried out by means of quantitative analysis of six rain gauges. It was found that the highest occurrences of impacts, are located in the central areas of the city, as well as the highest rainfall totals. In fact, Ubatuba/SP suffers from very high rainfall totals and has a singularity on the climate...
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Anatolia is situated in the Eastern Mediterranean region between 36 – 42N and 26 – 45E. The geological records of paleoglaciations in the high terrains of Anatolia are key archives to quantify paleoclimate change in the Eastern Mediterranean area. The climate of the Eastern Mediterranean region is influenced by three main atmospheric systems: the main middle to high latitude westerlies, the mid-latitude subtropical high-pressure systems, and the monsoon climate. Glacial geological studies in Turkey have started in the late 19th century. Glacial deposits are found mainly in the eastern, northeastern and southern part of the Anatolian Peninsula. Anatolia is the fundamental element to understand the interactions between paleoenvironment, climatic variations, and development of the human societies. As the Taurus and Black Sea Mountains are sensitively situated for the paleoclimatic reconstructions, a chronostratigraphic framework on the paleoglaciation should be elaborated. The timing of the Last Glacial Maximum (LGM) in Anatolia is still unknown. Our first results from Kavron Valley (Kaçkar Mountains, NE Turkey) are encouraging for the reconstruction of paleoglaciations in Turkey and related paleoclimatological interpretations although it is presently difficult to pinpoint the classical Last Glacial Maximum – Younger Dryas – Little Ice Age moraine sequences in the field.
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Reanalysis data obtained from data assimilation are increasingly used for diagnostic studies of the general circulation of the atmosphere, for the validation of modelling experiments and for estimating energy and water fluxes between the Earth surface and the atmosphere. Because fluxes are not specifically observed, but determined by the data assimilation system, they are not only influenced by the utilized observations but also by model physics and dynamics and by the assimilation method. In order to better understand the relative importance of humidity observations for the determination of the hydrological cycle, in this paper we describe an assimilation experiment using the ERA40 reanalysis system where all humidity data have been excluded from the observational data base. The surprising result is that the model, driven by the time evolution of wind, temperature and surface pressure, is able to almost completely reconstitute the large-scale hydrological cycle of the control assimilation without the use of any humidity data. In addition, analysis of the individual weather systems in the extratropics and tropics using an objective feature tracking analysis indicates that the humidity data have very little impact on these systems. We include a discussion of these results and possible consequences for the way moisture information is assimilated, as well as the potential consequences for the design of observing systems for climate monitoring. It is further suggested, with support from a simple assimilation study with another model, that model physics and dynamics play a decisive role for the hydrological cycle, stressing the need to better understand these aspects of model parametrization. .
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" Report ; no. TDR-269 (4560-50)-2)."
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At head of title: International Biological Program, United States National Committee, Aerobiology Program.