Abstract
The concern for climate change had led to an upsurge in climate research with most of
such efforts concentrated on rainfall. The thrust of such studies showed that annual
rainfall series was on the decrease in most parts of the Sahelian region of Africa since late
1960s with a slight recovery from the year 2003 onwards. The objective of this paper is to
analyze monthly rainfall variations for further evidence of climate change in Sokoto state,
Nigeria from 1926-2015. The period was divided into three slices viz: 1926-1955, 1956-
1985 and 1986-2015 for comparative purposes. Monthly rainfall data obtained from
Nigerian Meteorological Agency (NiMet) were subjected to Kendall tau Statistic, Rainfall
Seasonality Index (RSI) and Rainfall Anomaly Index (RAI) for analyses. The result showed
an upward trend in monthly maximum rainfall totals during all the slices, though not
statistically significant. The rainfall regime has changed from being ‘most rains in 3
months or less’ to being ‘markedly seasonal with a long dry season’. The monthly rainfall
anomaly pattern revealed a marked increase in rainfall during the period of relative
rainfall maximum (August) for all slices except 1956-1985 and pronounced decrease
during the period of relative rainfall minimum (May-June) for all slices except 1986-2015.
The changing rainfall regime as well as pronounced decrease in rainfall during the period
of relative rainfall minimum are further evidence of the changing climate. It is
recommended that seasonal rainfall prediction model be developed to accurately predict
rainfall anomalies for agricultural planning in the region.
Comments: no replies