Relação entre a precipitação pluvial na região Nordeste do Rio Grande do Sul e a temperatura da superfície do mar dos oceanos Atlântico e Pacífico

Abstract

Some studies supply evidences of that the Atlantic and Pacific oceans play a significant role in the climatic fluctuations that occur in the south region of Brazil, influencing mainly in the pluvial precipitation of this region. Among the more used exploratory variable and searched there is the sea surface temperature (SST). Then the main objectives of this work are to identify the standards of anomalies of the SST of the Atlantic and Pacific oceans and they relations in the pluvial precipitation in the Northeast region of Rio Grande do Sul in the October to the March months and to analyze the possibility of the previsibility of the pluvial precipitation with some months of antecedence. Thus the homogeneous pluvial precipitation regions had been defined in Rio Grande do Sul. To define these regions, the method of K-means classification was applied on scores of the first main components, derivatives of the data set of monthly pluvial precipitation of 25 meteorological stations, in the period of october to march from 1982 to 2005. The defined homogeneous region was chosen as Northeast region of Rio Grande do Sul, being verified the relation between the variability of the monthly pluvial precipitation and the temperature in the surface of the Atlantic and Pacific oceans. The results had shown that the first main standard of 7 oceanic areas had presented highly significant correlation with the accumulated pluvial precipitation of january and february in this region, and consequently a correlation with the quality of the grape. Also, the high previsibility of the predominant standard in the months of january and february from anomalies of the SST average of october-november was evident.