NIGERIAN JOURNAL OF SPACE RESEARCH 6: 89-101, 2009 MAY 30
© 2009 NASRDA Centre for Basic Space Science. All rights reserved.
Spatial Patterns of Twentieth Century Mean Seasonal
Precipitation over West Africa
H. C. Nnamchi, R. N. C. Anyadike and C.N. Emeribe
Programme in Climate Dynamics, Department of Geography, University of Nigeria, Nsukka,
410001 Nigeria
hyacinth.nnamchi@unn.edu.ng
Abstract
This paper presents the spatial distribution of seasonal precipitation over West Africa,
using the 2.5° latitude by 3.75° longitude grid version of the Hulme 98 dataset for 1900 to
98. It is found that long-term mean precipitation increases in amount and spatial spread
in the course of the year so that the rainfall field penetrates most inland, up to 17.5 0N in
July-August, when the seasonal maximum amounts above 800mm is also observed in the
southwestern part. Seasonal distinction between the drier and wetter parts of the year is
more discernable in the inland locations. The Little Dry Season (LDS) is not noticed in the
eastern and western extremities, as well as in the northern parts. Similarly, the ‘GhanaTogo gap’ is not noticeable during the wetter months. There is also a seasonal reversal of
the locations of maximum rainfall which is centred on the Cameroon Mountains – Niger
Delta area in the drier months and on the Fouta Djalon – Guinea highlands in the wetter
months.