Rainfall anomaly patterns over Northeastern Brazil (NEB) are re-examined considering the effects of the El Niño/Southern Oscillation (ENSO) and the Tropical Atlantic (TA) during the season preceding the northern NEB rainy season. In the absence of significant sea surface temperature anomalies (SSTAs) in TA, during the initial and development phases of the ENSO, precipitation anomalies in DJF are possibly due to teleconnection patterns associated with the rearrangement of the Walker cell, and in MAM, due to the extratropical teleconnection patterns. Simultaneous ENSO and significant SSTAs in the TA act to reinforce or to inhibit the precipitation anomalies. The same signal SSTAs in the tropical south Atlantic (TSA) and in the eastern Pacific weaken the precipitation pattern over NEB. When the SSTAs in the TSA are non-significant or with equivalent magnitudes of those in the ATN, but with opposite signal of the SSTAs in the eastern Pacific, the SSTAs in the ATN and the ENSO-related atmospheric circulation leads to reinforced anomalous precipitation patterns. Independent of the ENSO, the TA influence in the precipitation variability is remarkable for the TSA. The relevant aspect presented here is the important role of the TSA in the NEB precipitation variability. Thus, the TSA monitoring is essential for seasonal climate forecasting purposes.
Northeastern Brazil; precipitation; sea surface temperature; tropical Pacific; tropical Atlantic
