Características da precipitação na Amazônia através de dados de superfície e do satélite – TRMM

Abstract

In this study analyze the behavior of the precipitation in Brazilian Amazonian. The analyses were made using a monthly series of precipitation generated by the University of Delaware (USA) covering the period of the period from 1950 to 1996. It was also used daily data precipitation from Tropical Rain Measuring Mission (TRMM) satellite, during the period of 1998 to 2001. The analyses of the annual and seasonal totals of precipitation revealed the existence of three centers of maximum in Amazonian. They are related to the position of ZCIT, of ZCAS, of Bolivia Highs, the Squall Line and topographic effects. The Summer is rainy over a large área and the Winter is the driest period. In general, the rainy seasons begins in October and it finishes in April, with exception of the North section where is from February to August. The Summer and Autum answer for about 70% of the annual total of precipitation. The first harmonic of the monthly series of precipitation shows that the phase maximum, varies from January to March. The largest width happens in the Northeast and in the South, and the minimum in the Northwest of the área. During La Niña events, it happens a reduction in the Northeastern and Southern of this área, while during situations of El Niño, this reduction is more pronounced in the Northeastern part. The phase underwent significant changes in the South área of the states of Pará and Amazonas, mainly during La Niña events. Along the latitude of 4°N, the amplitude is largest in 52° W and between 68° W and 71° W, during years of La Niña. The correlation between the precipitation to the mid latitude cold fronts and the convection in the área. In the Northwest área, the correlations show the existence of front cold that propagates the convection from West to East. The precipitation convective dominates mosto f Amanonian, mainly in the region East and Northwest, but the stratiform component is significant during the astral Summer, mainly in the Southwest and North área.