Recherche de tendances récentes dans les séquences sèches : cas des stations synoptiques du Bénin

The deficit of last decade rain in West Africa and particularly in Benin pushes us to make the analysis of tendencies of the dry sequences of the tabular stations from daily raining data. The general objective of this survey is the research of rupture and tendency in the dry sequence sets in the period from 1970 to 2009 from daily raining data of the tabular stations of Benin. We have extract of data daily raining of six stations of Benin, the maximal dry sequence length and the dry sequence average in the period from1970 to 2009 and we analyzed the variation of maxima of length of dry sequences and their average on the period from 1970 to 2009.Then, to deepen analyses of tendency, we achieved some statistical tests have been applied to the set of the maxima dry sequence with the help of the software Khronostat. From the results, we can retain the existence of a reduction tendency of the dry sequence with breakpoint in 2006 in the station’s Cotonou. In opposition, an increase tendency with breakpoint in 1978 in the station’s Natitingou. And, a stationary tendency without breakpoint in the set of maxima of dry sequence length to the station of Bohicon, Savè, Parakou and Kandi.