Ismail1 A and Oke*2 I.A
Abstract
Birnin Kebbi is in the North West geoploitical zone of Nigeria. The major occupation of the people in this region is farming, which depends on rainfall and other factors. This article presents statistical and trend analyses of the rainfall in Birnin Kebbi. Rainfall data in the region for a period of 1915- 2007 were collected from archives. The existence of trend and statistical analyses were conducted on yearly total rainfalls using non-parametric techniques. The study revealed that overall averages of yearly and monthly total rainfall were 787.53±24.03 mm and 112.21 ±25.31 mm respectively. Yearly total rainfall has Mann-Whitney of 112, 40 and 50 between 1915 and 1946; 1947 and 1977 and between 1978 and 2007. These parameters show that there are significant trends in the rainfall in term of yearly total for the period. Sen’s estimator revealed that there are significant upward trends for yearly total (1.03mm/year), (10.33 mm/year) and (-9.04 mm/year) within a period of 1915- 1946; 1947 – 1977 and 1978 – 2007. There is a significant downward trend for yearly total of 9.04mm/year within a period of 1978 – 2007. It was concluded that there is a significant downward trend in the yearly total and mean rainfalls at Birnin Kebbi in the last three decades (30years), which can be attributed to climate change.