Transporte de Umidade nos Climas Presente, Passado e Futuro sobre a América do Sul (Moisture Transport to Weather Present, Past and Future of South America)
DOI:
https://doi.org/10.26848/rbgf.v6i4.233087Keywords:
RegCM3, convergência de umidade, América do Sul, erros sistemáticos.Abstract
Objetivando verificar se o modelo regional RegCM3 consegue representar o clima da América do Sul (AS), foi realizado as médias mensais da precipitação e umidade específica no inverno e verão para o clima presente (1991-2008). Em seguida, avaliou-se o fluxo de umidade integrado verticalmente para diferentes climas, isto é, passado (1961-1990), presente (1991-2008) e futuro (2071-2100), em três áreas da AS: Nordeste do Brasil (NEB), Amazônia (AMZ) e Bacia do Prata (LPB). As análises realizadas para o clima presente, mostraram que no verão, o RegCM3 representa o padrão de precipitação orientado na direção noroeste-sudeste, caracterizando a Zona de Convergência do Atlântico Sul (ZCAS). No entanto no inverno, o RegCM3 torna a Zona de Convergência Intertropical (ZCIT) mais confinada meridionalmente na região continental. Em síntese, os erros relacionados à ZCAS e ZCIT parecem ser importantes para explicar a superestimativa de precipitação na Amazônia Central e oeste da AS. Com relação ao fluxo de umidade, observou-se de modo geral, que o fluxo médio da AMZ e NEB fornece maior parte de vapor d’água na borda leste, sugerindo que as contribuições dos ventos alísios do Atlântico Norte e Sul são igualmente importantes para a entrada de umidade durante o verão e inverno. Uma vez que, na AMZ e no NEB o transporte de umidade foi maior no clima futuro, comparadas com o clima passado e presente em ambas as estações. Em relação à LPB, observou-se que a região é úmida no verão (presença de Jato de Baixos Níveis) e seca no inverno (Monção na AS). A B S T R A C T Aiming to verify whether the RegCM3 regional model can represent the climate of South America (SA), was analyzed the monthly average of rainfall in winter and summer, for the present climate (1991-2008). Then, it was evaluated the vertically integrated moisture flux for different climates, that’s it, the past (1961-1990), present (1991-2008) and future (2071-2100), in three areas of the AS: Northeast Brazil (NEB), Amazon (AMZ) and the La Plata Basin (LPB). The analyzes performed for the present climate, showed that in summer, the RegCM3 represents the rainfall pattern oriented in the northwest-southeast direction, characterizing the convergence zone of the South Atlantic (SACZ). However in winter, RegCM3 makes the Intertropical Convergence Zone (ITCZ) more confined meridionally in the continental region. In summary, the mistakes related to the SACZ and ITCZ seem to be important to explain the overestimation of precipitation at Amazon Central and west AS. Regarding the moisture flux was observed generally that the average flow of the AMZ and NEB provides most of the water vapor on the eastern edge, suggesting that the contributions of the trade winds of the North Atlantic and South are equally important to ingress of moisture during the summer and winter. Once the moisture transport was greater in the future climate in AMZ and NEB, compared with the past and present climate in both seasons. Regarding the LPB, it was observed that the region is humid in summer (presence of Low Level Jets) and dry in winter (Monsoon in SA). Key-words: RegCM3, moisture convergence, South America, systematic errors.Downloads
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Copyright (c) 2013 Maytê Duarte Leal Coutinho, Kellen Carla Lima, Cláudio Moisés Santos e Silva
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