Trends and discontinuities in regional rainfall of West and Central Africa: 1951-1989

Standardized regional mean annual rainfall series are analysed over the per iod 1951-1989 from a data set of 891 rainfall stations which covers 23 coun tries of West and Central Africa. Missing values are estimated by using reg ionalized indexes computed on the basis of a morpho-climatic delimitation o f 44 homogeneous climatic units. Searches for statistical discontinuities i n rainfall series show no discontinuity for most units of Central Africa. F or several units of West Africa the first discontinuity occurs at the end o f the 1950s. The main discontinuity period occurs between 1968 and 1970, fo llowed by a second one at the beginning of the 1980s. Rainfall deficit is g reater north of 10 degreesN, and is also important in the Guinean Mountains and on the northern coast of the Gulf of Guinea, west of the Atakora Mount ains. Regions leeward of mountainous areas experienced moderate rainfall de crease.