IMPACT OF CLIMATE CHANGE ON WEST AFRICAN MONSOON FEATURES AND THEIR RELATIONSHIP WITH CONVECTION AND PRECIPITATION

Abstract

West African region, particularly over Sahel region, has experienced a long-term climate variability and climate change during the last decades. This episode has severe consequences for local population whose economy depends mainly on rain-fed agriculture. Therefore, improved skilled prediction of the monsoon rains over longer time-scales would be of enormous benefit, aiding in the mitigation of high-impact events. As part of efforts to improve on Monsoon system, this study investigates how global warming affect West African Monsoon features characteristics such as AEJ and AEWs and their interaction between convection and precipitation patterns. The latest version of the International Centre for Theoretical Physics Regional Climate Model (RegCM4) driven by three CMIP5 Global Climate Models (GCMs) is used at 25 km of grid spacing over West Africa. A set of experiments was performed to investigate the impact of lateral boundary forcings on the simulation of monsoon precipitation and the relationship with regional circulation features. In particular, we examine and inter-compare the models performance with theirs ensemble-mean in simulating the mean climatology, convection patterns and West African Monsoon features for both historical (1985-2004) and future (2080-2099) periods during the boreal summer season (JJAS). Secondly, we examine how convection, AEJ, AEWs, precipitation and their interaction are changing in the future (2099-2080, under two GHG scenarios RCP4.5 and RCP8.5 and the referenced period 1985-2004).