Changements d'etats de surface et evolutions spatio-temporelles des precipitations sur le bassin versant de la Marahoue (Cote d'Ivoire) [ Performance analysis of few statistical indices to characterize drought conditions in Cote d'Ivoire ]

Marahoue Watershed faces significant variability of its bioclimatic conditions. The aim of this study is to analyze the dynamics of land use between 1986 and 2006 and the recent trends in rainfall especially after the 2000s. To achieve this aim, a diachronic analysis of satellite images and the spatial and temporal variability of rainfall over the period 1970-2008 using statistical methods were used. The results come as bare soil/habitats and crops increases significantly when the watercourse, wetlands, dense forests and forest galleries regress sharply. The increase in bare soil/habitats and crops shows the important role of human activities in the dynamics of land use. In addition, the rainfall decrease in watershed from 1970 with large deficits in the order of 15%-37% has also contributed to the drying up of watercourses and reduction of wetlands. Moreover, the results show a recovery rainfall after 2000 throughout the watershed.