THE ROLE OF SEA SURFACE TEMPERATURE IN THE RAINFALL REGIME IN SUB-SAHARAN AFRICA

This study sought to understand the role of the surface temperatures of the ocean and continent in the variability of rains in sub-Saharan Africa, contributing to the improvement of weather forecasting and prevention of extreme events in the region.Through perturbation experiments using a climate model of intermediate complexity,we seek to understand the roles of sea surface temperature (SST) of ocean basins around the sub-Saharan Africa and the surface temperature in Southern Africa, in defining the spatial distribution of Spatial distribution of rainfall in the region of action of Intertropical Convergence Zone (ITCZ) which assumes an approximate shape of an "inverted S" during the quarter December-January-February in this continent, due to connections with other systems of the same scale. By comparing the regional perturbation experiments of SST and the continental surface temperaturewith respect to the climatology we came to the conclusion that the SST in the Atlantic and Indian Oceans have major contribution in the formation of "inverted S" of precipitation than the continent's surface temperature. Comparing these two ocean basins, the Indian SST has predominant role in the climate variability in sub-Saharan Africa, modulating the position and intensity of the ITCZ and therefore the formation of their spatial distribution across the continent.  

The Influence of the Atlantic Meridional Overturning Circulation in the Definition of the Mean Position of the ITCZ North of the Equator. A Review Luis Aimola1

The Intertropical Convergence Zone (ITCZ) is considered the most important atmospheric system in the generation of precipitation in the tropics. Although in the present climate the annual average insolation is symmetrical around the equator, the ITCZ is positioned north of the equator, also having the maximum of precipitation there. In this review article we describe the vision developed in recent studies of the influence of the Atlantic Meridional Overturning Circulation on the Hadley cell in determining of the ZCIT's position asymmetry. We indicate the importance of strengthening this research topic in face of possible future displacements of the ITCZ with global warming and the consequent tropical rain regime changes.A Zona de Convergência Intertropical (ZCIT) é considerada o sistema atmosférico mais importante na geração de precipitação nos trópicos. Embora no clima presente a insolação média anual seja simétrica em torno do equador, a ZCIT se posiciona ao norte do equador apresentando ali também o máximo de precipitação. Neste artigo de revisão descrevemos a visão desenvolvida em trabalhos recentes sobre a influência da Circulação de Revolvimento Meridional do Atlântico sobre a Célula de Hadley na determinação da assimetria de posição da ZCIT. Indicamos a importância de se aprofundar este tópico de pesquisa em face a possíveis futuros deslocamentos da ZCIT com o aquecimento global e as consequentes mudanças no regime de chuvas nos trópicos