On Determining Effective Onset of Rainfall and its Variability over Sokoto, Nigeria

Abstract

Peasant crop farming is the major economic activity especially in the sahel and sub-humid area of Africa whose fortunes can easily be affected by fluctuations to regime. In the light of the above this study investigated the historical record rainfall data of 1971 – 2015 were acquired from Environmental Management Programme Federal University of Technology. A drought monitoring and early warning (EW) methodology base on intra-seasonal Rainfall monitoring Index (IRIM) were adopted. The finding revealed that effective onset rainfall have been variable with the mean onset date at 40th pentad (20th July, the year with an early onset date were found to have higher rainfall distribution and intensity (figure 3a – i ) of the two rainfall extreme (flood and drought), the result revealed a prevalence of drought (table 2). The mild drought (0.1<IRMI<1) revealed 28%, severe drought (0.010<IRMI<0.1) 8% and very severe drought (IRMI<0.01) representing 7% owning to variability in the inter-seasonal onset rainfall we effective date to rain fed farmers for proper agricultural planning in the region