On the Dynamics of Droughts in Northeast Brazil: Observations, Theory and Numerical Experiments with a General Circulation Model

摘要: Abstract It is proposed that a possible mechanism for the occurrence of severe droughts over northeast Brazil establishment thermally direct local circulation which has its ascending branch at about 10°N and descending adjoining oceanic region. The driving this anomalous provided by warming due to enhanced moist convection associated with warmer sea surface temperature anomalies northern tropical Atlantic, cooling colder in southern Atlantic. combined effects forced subsidence reduced evaporation moisture flux convergence produces drought conditions Brazil. We have examined monthly mean Atlantic rainfall two selected stations (Fortaleza, 3°46′S 38°31′W Quixeramobim, 5°12′S 39°18′W) 25 years (1948–72). found most sever...