Inter-Decadal Nature of Rainfall Character Over Sudano-Sahel, North-West Nigeria

Abstract

The study investigated the spatial pattern of decadal variations in annual rainfall amounts in the Sokoto-Rima River Basin, Northwestern Nigeria. Rainfall dataset which is available on high-resolution (0.5 x 0.5 degree) grids resolution from the Climatic Research Unit CRU TS 3.21 of the University of East Anglia, Norwich, United Kingdom was used for the period 1943-2012 for Bunza, Dakindari southwest of the study area, Gulma, Augi, northwest of the Sokoto-Rima basin, Goronyo, Galadi, northeast Maje and Dan-Dume stations southeast of the basin. Correlation of CRU TS dataset was performed with measured rainfall data (Yelwa climatic station) from Nigerian Meteorological Agency, using the Pearson Product Moment Correlation statistic at 0.05 significant levels. In general, the study found that periods of downward fluctuations in annual rainfall below mean values corresponded with period of rise in global temperature occasioned by anthropogenic greenhouse gases emission. The study revealed a significant decrease in the annual rainfall from late 1980 onwards.

Key Word: Rainfall, decadal departure, River Basin, Rainfall variation. Climate Research Unit