Résumé
This study aims at evaluating the information carried by the 17O-excess composition of precipitation in the sub-humid part of West Africa. Located at the southern border of the Sahelian band, the so-called “Sudanian Climatic Zone”, characterized by annual precipitation of 1200-1400mm, plays a crucial role in providing water to large African watersheds such as the Niger river’s one, and the Lake Chad catchment. Surface-atmosphere interactions were shown to influence convective processes in the semi-arid Sahelian band, with positive feedbacks between vegetation land cover and rainfall. Less focus has been put on the more humid Sudanian Zone, although surface-atmosphere interactions may have an important influence on the control of rainfall variations, and therefore on water resource availability in these watersheds.