NORTH NORTHEAST BRAZIL RAINFALL AND ITS DECADAL-SCALE RELATIONSHIP TOWIND STRESS AND SEA-SURFACE TEMPERATURE

In this study low-frequency variability of rainfall data for the North part of Northeast (NNE) Brazil is examined. The time scale dependence of NNE Brazil rainfall and the associated sea surface temperature (SS T) field is also described. Area averaged monthly rainfall data for th e NNE Brazil from 1911 to 1989 exhibits not only a distinct interannua l behavior but also significant decadal variability. Examination of a 30 year data set of tropical Atlantic SST and wind stress show similar behavior. It was found that the relationships between SST, NNE Brazil rainfall and meridional pseudo-wind stress on the interdecadal time s cale are very similar to those on the interannual and seasonal time sc ale. In both time scales, SST in the Tropical Atlantic are in phase wi th the meridional displacement of the Intertropical Convergence Zone a nd associated meridional pseudo-wind stress and out of phase with rain fall.