Análise da influência da salinidade da superfície do mar na precipitação das Regiões Nordeste e Amazônia Oriental do Brasil.

Abstract

Sea Surface Salinity (SSS) is a variable that has been studied by several authors as a significant indicator of terrestrial precipitation in different parts of the planet. Modulated mainly by evaporation (causing an increase in SSM) and precipitation (causing a decrease in SSM), SSM is an important variable that influences rainfall variability in different parts of the continents, often surpassing traditional Sea Surface Temperature (SST) indices. In this study, SSM of the Tropical Atlantic Ocean is analyzed as a variable that has a great influence on precipitation in a large part of the Northeast Region (NEB) and Eastern Amazon of Brazil. Statistically significant correlation indices between SSM and precipitation are found mainly between six and three months in advance. In areas south of the NEB and Eastern Amazon of Brazil, the contribution of the SSM of the Tropical Atlantic Ocean to precipitation begins to influence significantly during the austral winter (about six months in advance), and in regions further north of the NEB and Eastern Amazon of Brazil this contribution occurs especially during the austral spring (about three months in advance). Significant indices for the confidence level of α 0.01 between the correlation of the SSM of the Tropical Atlantic Ocean and precipitation in the NEB and Eastern Amazon of Brazil occur mainly in areas of the Equatorial Atlantic and South Atlantic. Four distinct rainy seasons were identified in the study area: from November to March (NDJFM), December to April (DJFMA), January to May (JFMAM) and March to July (MAMJJ), where an individual study was made that each rainy season suffers from the variability of the SSM in the Tropical Atlantic Ocean. This study used Sea Surface Salinity data obtained from the Met Office Hadley Centre. This monthly dataset is available from January 1900 to the present on a 1° x 1° resolution grid. Precipitation data were obtained from the Climate Prediction Center/National Oceanic and Atmospheric Administration (CPC/NOAA). These data are daily and are available from 01/01/1979 to the present on a 0.25° X 0.25° resolution grid. The study period of this work is 30 years (January 1991 to December 2020).