Introduction

Climate variability in the tropical Atlantic region and the land that surrounds it represents a difficult problem in terms of large-scale circulation and ocean-atmosphere-land interactions, with important economic and social impacts (CLIVAR Initial Implementation Plan, June 1998). During recent decades a large multi-decadal swing in the Atlantic climate has been observed and it is believed to be caused by interactions between the Atlantic Ocean and the overlaying atmosphere. These climate swings are directly or indirectly related to the tropical Atlantic region where surface temperature variability and the associated changes in winds, sea level pressure, intertropical convergence zone (ITCZ), and the Hadley circulation occur on interannual to decadal time scales. These covariant fluctuations are collectively called Tropical Atlantic Variability (TAV). more