The nature of rainfall fluctuations in subtropical West Africa ( Guinea Sahel Soudan).

Abstract

Areally averaged, normalized rainfall departure series for the yr 1901-75 are derived for four semi-arid sub-Saharan climatic zones; the Sahelo-Saharan, the Sahel, the Soudan and the Soudano-Guinean. Similar series are derived for 4 or 5 regions within each zone and the regional series are itercorrelated. In general, rainfall fluctuations in the W African subtropics are more commonly characterized by a contraction or expansion of the desert belt, rather than by its north-south displacement. -from Author