Trend and variability in western and central Africa streamflow, and their relation to climate variability between 1950 and 2010

Over the last 60 years, the Sahel has experienced two decades of persistent excessive rainfall in the 1950s-60s, followed by two decades of rainfall deficits. Recently, a partial recovery in annual rainfall amounts, particularly pronounced over the Central Sahel, has been discussed (Lebel and Ali, 2009). Several studies have investigated the impacts of climate changes on hydrological systems, but are mostly limited to the catchment scale. Here, we aim at better understanding how climate fluctuations and changes impact hydrological systems at the regional scale. Such studies are particularly important to reduce the uncertainties in developing future river-flow scenarios and for large-scale water resource development. This study can be depicted in three parts :
Generate the first large-scale river flow database for West and Central Africa;
Quantify and compare trends in annual effective precipitation and river flow over West and Central Africa; Investigate the relative contribution of fluctuations and trends in streamflow variability (interannual and decadal), and define the associated teleconnections with large scale climate variability, e.g. Global sea surface temperature (SST) anomalies.