Influence of the Tropical Atlantic Ocean’s Sea Surface Temperature in the Eastern Northeast Brazil Precipitation

Abstract

An analysis of the rainfall of the Eastern Northeast Brazil (ENEB) during the period from April to June and the processes of ocean-atmosphere interaction were performed during different episodes of Sea Surface Temperature (SST) inter-hemispheric gradient of Atlantic tropical (GRAD). For this, we used a dataset covering the 1981 to 2010 period, composed by: monthly data of accumulated precipitation of the Global Precipitation Climatology Project (GPCP); surface fluxes obtained from reanalysis of the National Center for Environmental Prediction (NCEP); vertically integrated moisture flux divergence of the global model of European Centre for Medium Range Forecasting (ECMWF) reanalysis; SST data from the NCEP. Seven GRAD_S (southward SST gradient in the intertropical Atlantic) and five GRAD_N (northward SST gradient in the intertropical Atlantic) were selected. When the South Atlantic Ocean is warmer, the oceanic and atmospheric conditions are favorable to higher monthly precipitation near to the ENEB. We also observed a pronounced moisture convergence over parts of the ENEB during both, GRAD_S and GRAD_N episodes. The weather phenomena that operates remotely amplifying or inhibiting the rain also helps the rainy season; however, it appears that the contribution was greater than the spatial distribution of rainfall intensity.