Vegetation feedback on Sahelian rainfall variability in a coupled climate-land-vegetation model

Abstract

Rainfall variability in the Sahel region shows a dramatic drying trend from the 1950s to the 1980s. Yet, most atmospheric general circulation models (AGCM) forced by observed sea surface temperatures (SSTs) were not able to reproduce the amplitude of this multi-decadal variation. Here, we investigate the sensiti- vity of Sahelian rainfall to vegetation-atmosphere interaction. We coupled the simple dynamic vegetation model (SVege) and the ECHAM4-AGCM and for- ced the system by observed SSTs. We show that vegetation-climate feedbacks amplify the decadal rainfall variability and that the coupled system simulates realistically the observed multi-decadal variations in Sahelian precipitation.