Um estudo dos fluxos horizontais e verticais do vapor d'água na troposfera sobre o Nordeste do Brasil.

Abstract

Two constrasting periods with respct to rainfall were studied in the Northeast of Brazil, one wet and other dry. These periods were find to be those which showed the biggest deviations with respect to the long term mean during the ten years period spanning from 1969 to 1978. During the wet period (June 16 to 20, 1975), the main system that produced the rainfall was a frontal system from the south. Cluster from the ITCZ and breeze systems also contributed to the rainfall amounts. In the dry period (may 11 to 15, 1976), the most significant fact was a "blocking" of the systems which produce rainfall over Northeast. Few rainfall amounts registered along the coast may be atributed to the local breeze systems. It has been also abserved strong convective movements in the North Atlantic, in contrast with the anomalous subsidence over the Northeast. The fields of vertical motion (kinematic), horizontal divergence of water vapour and vertical flux of humidity, had been showed more organized during the wet period in comparison to the dry period, although there is not a perfectly defined pattern. I.e. , those fields had showed to be of the same sign along the troposphere in the wet period, but they alternate sign during the dry period, in general. There is weak indication that the vertical flux of humidity is more important in the northern part of the Northeast, while the horizontal transport of water vapour shows more important in the southern. The fact that is not a well defined pattern of the vertical movements, and the vertical and horizontal transport of water vapour, may indicate that there is the necessity of at least two synoptic observations in order to detect all the transformations in the tropospheric structure.