Influência da temperatura da superfície do mar próximo à costa leste na precipitação do Nordeste do Brasil.

Abstract

In this work. observational and numerical studies are performed in order to evaluate the impact of a perturbation in the sea surface temperature (SST) in Atlantic Ocean on the precipitation of Northeast Brazil (NEB). The perturbed region is located near the NEB's east coast. The observing available data are fields of SST anomalies and precipitation at the state of Paraiba, both based on seven days moving means for the period from January through May of 2000. Furthermore, numerical experiments for a ten-days period are performed using the numerical model RAMS. Simulations with and without the SST perturbation are run for a dry and a wet period. The results of the observational study show that an increase in Atlantic Ocean SST, near the NEB's east coast, causes a positive impact on Paraiba's precipitation. This impact occurs mainly in the state's east part. The numerical experiments for the dry period support the observational evidence of a positive impact of SST anomalies on the precipitation of NEB's east part. On the other hand, during the wet period the increase in precipitation is restricted to the perturbed area, causing almost no influence on the continental area. These results suggest that the impact of the SST on precipitation depends on the atmospheric conditions during the studied period. Nevertheless, from a general point of view, one can expect a positive SST impact on precipitation in the continental áreas near the ocean.