1. School of Agricultural, Earth and Environmental Sciences, Centre for Water Resources Research; University of KwaZulu-Natal; Scottsville South Africa
2. ICRISAT; Matopos Research Station; P.O. Box 776 Bulawayo Zimbabwe
3. Institut de Recherche pour le Développement (IRD), Laboratoire d'Océanographie et du Climat (LOCEAN), UMR 7159, IRD/UPMC/CNRS/MNHN, Institut Pierre Simon Laplace; Paris France