Evolução temporal de padrões atmosféricos em ano chuvoso na cidade de Salvador.

Abstract

The objective in this work is to investigate the temporal evolution of the mean and nomalous characteristics of the atmosphere, at the surface and in altitude, for a rainy year in the city of Salvador. The period of study is December 2005 to July 2006 and the climatologic basis is formed by the 1979-2010 period. NCEP reanalysis gridpoint data and INMET monthly precipitation data are used. Sea level pressure monthly mean fields show a small amplitude inverted trough on the Northeast eastern coastal area and the Atlantic, from April to July of 2006, an above normal rainy period. This structure is also found in the 850 hPa mean wind field, in April and May. To the south of this trough, over the subtropical Atlantic, there is a trough in the westerlies, a result that indicates an interconnection between tropical and extratropical circulation systems. The 200 hPa mean wind field shows westerlies with wind speeds higher than 20 m/s to reach latitudes to the north of 15ºS over South America, in the four-month rainy period. Below normal sea level pressure and cyclonic circulation at 850 hPa are outstanding anomalies found over eastern Northeast Brazil and the adjacent oceanic area in April 2006.