Search results for "états de surface"

Impact de la variabilité climatique et de la dynamique des états de surface sur les écoulements du bassin béninois du fleuve Niger

2007

This thesis has for principal objective to establish a diagnosis of the hydrological system of the beninese basin of the Niger River, in the context of the rainfall decrease which has severely affected Africa since the 1970s. To achieve this goal, this study was based on three main types of data :weather (rainfall, temperature, relative humidity, potential evapotranspiration, real evapotranspiration), hydrological (stream flow, recharge) and of land surface conditions (land cover types, NDVI).It considers three key aspects. The first one, devoted to the study of hydro-climatic variability over the period 1955- 1992, shows that the rainfall deficits of the 1970s and 1980s were largely amplif…