An Analysis of Rainfall Extremes in the Northern South America and Their Behaviors for Future Climate Based on A1b Scenario

Abstract

ABSTRACT:The Brazilian Amazon (BAMZ) and Northeast Brazil (NEB) regions have been facing intense climate extremes since the beginning of 21st century. In BAMZ, these climate extremes can modify the Amazon forest and its essential role in the local and remote climate. This study evaluated whether the extreme rainfall events in the both regions will be more intense and frequent in the future due to the increase of greenhouse gas emissions. An adapted version of the RX5day index was applied to distinguish between different types of extreme rainfall cases in the ETA model output for the decade 2089-2099 compared to the 1980-1990 decade. The results have shown that although the total rainfall is expected to be reduced by at least 1/3 (DJF) in the case of rare events, this kind of extreme rainfall will contribute with a higher amount of rainfall and will occur more frequently in both areas by the end of the 21st century. Heavy and very heavy events decrease for both areas (total rainfall amount and frequency). Results suggest that stakeholders must be prepared to cope with the population's need for assistance during floods and rainfall reduction and reinforces the need to adapt to worse climate extremes projections Keywords: Extreme rainfal events, Amazon, Brazilian Northeast, Climate Change, ETA model. ANÁLISE DOS EXTREMOS DE CHUVAS NO NORTE DA AMÉRICA DO SUL E SEUS EFEITOS NO CLIMA FUTURO COM BASE NO CENÁRIO A1BRESUMO: A Amazônia brasileira (BAMZ) e a região nordeste (NEB) têm passado por eventos climáticos extremos desde o inicio do século XXI. Na AMZ esses extremos climáticos comprometem a floresta amazônica e seu papel essencial para o clima local e não local. Esse estudo analisou se os eventos extremos de chuva em ambas as regiões serão mais intensos e frequentes no futuro devido ao aumento dos gases do efeito estufa. Uma versão adaptada do índice RX5day foi utilizada para distinguir entre os diferentes tipos de casos de eventos extremos para os resultados das simulações numéricas, provenientes das simulações com o modelo ETA para a década de 2089-2099 e comparada a década de [1980][1981][1982][1983][1984][1985][1986][1987][1988][1989][1990]. Os resultados mostram que embora se espere uma redução 1/3 no total de chuva (DJF) os eventos do tipo raro irão contribuir com uma quantidade de chuva maior e ocorrerão com mais frequência nas duas áreas no final do século XXI. Eventos forte e muito forte diminuirão nas duas áreas (total de chuva e frequência). Os resultados sugerem que os tomadores de decisão deverão estar _________________Revista Brasileira de Climatologia_________________ ISSN: 1980-055x (Impressa) 2237-8642 (Eletrônica) Ano 13 -Vol. 20 -JAN/JUL 2017 118 preparados para lidar com a necessidade de assistência da população durante as enchentes e redução de chuvas e reforça a necessidade de adaptação para projeções de eventos climáticos piores.Keywords: Chuva extrema, Amazônia, Nordeste Brasileiro, Mudanças Climáticas, Modelo ETA. 1.INTRODUCTIONBrazil has faced two major extreme climate events in this ...

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