Tropical Pacific and South Atlantic effects on rainfall variability over Northeast Brazil

The present paper reexamines the relative role of the tropical Pacific and tropical South Atlantic (TSA) on the rainfall over Northeast Brazil (NEB). For several variables, El Nino-Southern Oscillation (ENSO) and TSA-related anomalous patterns are obtained. These patterns are then compared to the combined ENSO and TSA-related patterns to infer the relative importance of the two oceanic basins on the rainfall over NEB. Analyses are done for austral summer and autumn seasons. Considering the composite technique, six cases are examined: Ell Nino and neutral conditions in the TSA, La Nina and neutral conditions in the TSA, ENSO neutral conditions and warm TSA, ENSO neutral conditions and cold TSA, El Nino and warm TSA, and La Nina and cold TSA. The most important result comes from the cases with competing influences of the tropical Pacific and the TSA. In some of these cases, the SST variability in the TSA is the determining factor of the NEB climate. The result of this study might be useful mainly for regional climate monitoring purposes. Copyright (C) 2006 Royal Meteorological Society.