The objective of this study was to investigate statistically the precipitation variability in annual scale from the states of the Bahia and Sergipe using daily precipitation data. From that, indexes of detection of climate changes were calculated to evaluate the relationship of the most significant indexes with the sea surface temperature (SST) anomalies of the Pacific and Atlantic oceans. The daily precipitation data used were for a period of 45 years of 75 meteorological stations supplied by the old net of the SUDENE available in the DSA and data of the of the SST anomalies obtained from NOAA. Influence of SST of the Pacific and Atlantic oceans on the precipitation of the studied area is evidenced. A decrease of CWD was verified; increase was observed in the number days with rain; therefore, the amount of annual total precipitation increased. Several stations presented positive or negative tendencies in all examined indexes, consequently, they are also related to regional aspects. Therefore, it is not possible to affirm that the climate alterations noted in the study area are due to the global climate changes.
Artigo recebido em 15/09/2012 e aceito em 15/10/2012 R E S U M O O objetivo deste trabalho foi estudar a dinâmica de variabilidade climática espacial e espectral da pluviosidade nos nove estados do Nordeste Brasileiro (NEB), utilizando a técnica multivariada de Análise de Agrupamento (AA) e a técnica espectral de Transformada de Ondeletas (TO) às médias mensais da precipitação pluvial e de mais 11 índices climáticos pluviais definidos pela OMM (Organização Meteorológica Mundial) obtidas a partir de dados diários de 258 estações meteorológicas e/ou postos pluviométricos referentes a um período de 47 anos . Na AA foram obtidos 4 grupos homogêneos (G1, G2, G3 e G4). As configurações espaciais obtidas demonstraram que para a maioria dos índices pluviais: G1 está pluviometricamente mais associado ao leste, G4 ao norte, e G2 e G3, indefinição. Os resultados da aplicação da TO mostraram que a escala de 4 anos apresentou os maiores níveis de intensidade de energia espectral e modulou em todos os grupos pluviais homogêneos obtidos boa parte das oscilações de frequência mais alta, da bienal a semianual, com destaque para a década de 1980. Pode-se afirmar que variabilidade climática da variável precipitação não foi afetada pelas mudanças climáticas; trata-se de uma variabilidade natural, cujos condicionantes e interações são intrínsecos ao ciclo natural atmosférico.Palavras-chave: agrupamento; ondeletas; índices pluviais. Application of Wavelets the Groups Homogenous Rainfall in the Northest Brazil A B S T R A C TThe objective of this work was to study the dynamics of climate variability in rainfall spatial and spectral in the nine states of Northeast Brazil (NEB) using the multivariate technique of cluster analysis (AA) and the technique of spectral Wavelet Transform (TO) to monthly averages rainfall and climate indices over 11 rain defined by WMO (World Meteorological Organization) obtained from daily data from 258 meteorological stations and/or climatic stations relating to a period of 47 years . AA were obtained in four equal groups (G1, G2, G3 and G4). The spatial configurations obtained showed that for most of the rain indices: G1 is associated with more rainfall to the east, north G4, and G2 and G3, undefined. The results of applying the TO show that the scale of 4 years showed the highest levels of intensity and spectral energy modulated in all groups homogeneous rainfall obtained much of the higher frequency oscillations, the biennial semiannual, especially for the decade, 1980. It can be argued that climate variability of the variable precipitation was not affected by climate change, it is natural variability, whose conditions and interactions are intrinsic to the natural cycle in the atmosphere.
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