Detection of hydrological impacts of climate change in Benin by a multifractal approach

This study analyzed the hydrological impacts of climate change over Benin synoptic stations from 1951 to 2010 using multifractal approach. This method is based on the study of temporal evolution of fractal dimension (D_f), multifractality index (α), co-dimension (C_1) and probable maximum singularity (γ_s). The comparison of the average values of yearly fractal dimension ((D_f)) obtained over the sub-period [1951-1970], [1971-1990] and [1991-2010] has shown and confirmed that [1971-1990] is a drought period in the region. However, the sub-period [1991-2010] is not the end of the drought over all the synoptic stations as known before, in West Africa. During the period from 1951 to 2010 over all synoptic stations, except Natitingou, there is a slight increase in γ_s exponent, controlling the extremes values of rainfall.  Thus, the evolution of the extremes rainfall over this period has a slight increasing tendency. These results confirm those obtained by some studies over the Oueme River Basin (Benin) using the climate index method. Thus, the multifractal approach is an excellent tool to evaluate the hydrological impacts of climate change using only three parameters. Key words: Climate change, multifractal, hydrological impacts, extreme rainfall, Benin.