Study of the rainfall regime variability in non-Sahelian West Africa from 1950 to 1989

In the countries around the Guinea Gulf, the rainfall regime has varied since the end of the 1960s. To specify some characteristics of this variability, time series of annual amount of precipitation, rainy season duration, amount of precipitation in dry seasons, and number of rainy days have been generated with a one-year time step from 1950 to 1989. Statistical procedures have been used to test the presence of a shift in the mean. To characterize the change in space and in time, the results of the tests have been synthesized using multiple correspondence analyses. This study reveals that the rainfall regime began to change around 1966 in Senegal and Guinea Bissau, and then in Guinea, Mall, Burkina Faso and the northern part of Benin. The Ivory Coast, Togo and the south of Benin have been affected to various degrees. In Cameroon and the Central African Republic, the change is not uniform or has been slight.