The African Hydrology project aims to quantify the role of changes in climate and land use on hdyrologic processes over the African continent. The project is a collaboration between Dr. Sharon Nicholson, Florida State Univeristy and NTSG.
The Sahelian region of West Africa has undergone extensive changes of land cover both as a result of dramatic changes in rainfall conditions and altered patterns of land use. These are likely to influence surface water balance of the region at the catchment scale and there is much evidence to suggest that the influence may extend to regional rainfall patterns. The proposed study aims at documenting the climatic changes that have occurred in the region over the past 50 years, to assess the land cover and productivity changes that have taken place over the same period, to distinguish between human and climatic factors in these changes, and to evaluate the potential impact of the vegetation changes on surface water balance and regional rainfall. It is well known that region has undergone a major change in its rainfall regime from a wet period that lasted throughout most of this century until the late 1960s and a dry period that has persisted ever since. Climate and remote sensing data will be used synergistically to quantify these changes in rainfall and other climatic parameters. Ecosystem models will be used to predict the "potential" vegetation cover of a wetter climatic conditions earlier in the century and of the drier conditions of recent decades. The actual current vegetation will be evaluated using remote sensing data. Assessments of the impact of vegetation changes on surface water balance will be made via an ecosystem model and via a conventional water balance model. Then the sensitivity of the large-scale climate to these changes will be examined using a general circulation model with a detailed, interactive land surface scheme.