Eventos extremos de precipitação no leste da Amazônia. / Extreme events of rainfall in Eastern Amazon.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

The aim of this study was to characterize the extreme events of rainfall in Eastern Amazon, to analyze on ocean-atmosphere conditions in global scale associated with intense occurrence periods of these events, to contribute for temporal variation comprehension of rainfall extreme events, as well as of determinant phenomena to its occurrence and to make further projections. For this purpose, Pluviometric Precipitation stations data from Brazilian National Institute for Meteorology (INMET) located in Belém, Breves, Altamira, Tucuruí and Marabá; and monthly data of precipitation from Delaware University (UDEL). In addition, available meteorological series at ESRL/PSD, particularly, sea surface temperature; u and v components; outgoing long wave radiation; atmospheric vertical movements; divergence fields; satellite images and oceanic and atmospheric climatic indices as Multidecadal Atlantic Oscillation, Pacific Decadal Oscillation (PDO), North Atlantic Oscillation, South Oscillation and Multivariated ENOS index. The methodology has included statistical techniques for rainfall analysis and behavior, as well as major phenomena that influence its annual regime, and events diagnostic as well. It was made class distribution of daily rainfall in Belém-PA, Eastern Amazon, and was clear that rainfall yearly total high values in that region were resulting from extreme events of rainfall that contributed, in average, with 37% from rain yearly total. These extreme events corresponded to 10% from total values of rainy days. There was a rising trend of these events in the last 10 years, attributed to upper troposphere cooling during that beginning of new PDO cold phase. Oceanic and atmospheric indices from Pacífic Ocean have shown to be a valuable tool for prediction of periods with extreme event occurrences. Trade winds, and mainly the sea surface temperature, were determinant factors for extreme events occurrence and development in Eastern Amazon, wavelets transform analysis has shown the energy and annual cycle present in precipitation regime of this region, as well as influence of high frequency phenomena as ENOS at rainy season of analyzed stations. Climate perspectives indicated that PDO is already in the new cold phase and its permanence is not known, much less its causes. However, if that new phase remain for more 15 to 20 years, certainly there will be rise in rainfall extreme events in Eastern Amazon, due to slowly cooling of upper troposphere, resulting in most vertical development of cumulonimbus clouds, responsible by high total values of rainfall.

ASSUNTO(S)

oceano atlântico odp meteorologia rainfall in amazon precipitação na amazônia extreme events, rainfall in belém, pdo eventos extremos

ACESSO AO ARTIGO

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