Recent Rainfall Trends and Variability in Sudano- Sahelian Region of Nigeria (1986- 2015)

Abstract

It was speculated that the droughts of the 1970s and 1980s that ravaged the Sahelian region of West Africa had ended following the occurrence of floods of different magnitudes in the last fifteen years or so which necessitated the need to re-examine the rainfall conditions in the region. Monthly rainfall data of five meteorological stations in the region were collected from the Nigerian Meteorological Agency (NiMet) over the period 1986-2015 and analyzed for trends and variability using linear regression model and coefficient of variation (C.V.%). A significant upward trend was found in annual regional rainfall composite of the region with similar patterns in annual rainfall series at all selected stations except Sokoto. The patterns of annual rainfall trend at individual stations did not reflect the patterns in their individual months. Further result showed that, annual rainfall was less variable in 1996-2005 decade at both Sokoto and Nguru stations while it was highly variable at Kano and Nguru in 1985-1995 decade. The observed rainfall patterns could be linked to dynamics of rain-producing systems in the region. The study has contributed to a deeper understanding of the recent changing rainfall patterns in the Sudano-Sahelian region of Nigeria. The implication of this study is that the climate change adaptation and mitigation policies designed based on apparent decline in rainfall from the late 1960s through 1980s need to be revisited and possibly replaced with new ones reflecting the current reality of increased rainfall in the region.