Characteristics of Rainfall Variations in Kaduna State, Nigeria

Rainfall trend and variation characteristics across Kaduna State in selected locations in the Southern, Northern and Central Kaduna State within 50 years period (1966-2015) from the Mann-Kendall test and variance coefficient revealed a significant monotone positive trend in only two out of the eleven (11) locations, while one location revealed an insignificant monotone negative trend. Kauru, where the trend was decreasing, is now witnessing an increasing trend of 113.333 mm of rainfall per year, and Kaduna North witnessing an increase of 58.889 mm per year. The increasing trend comes in the fourth decade (1996-2005). The result of the variance coefficient ranges from 0.065 to 0.351, which shows that there are no much variations in the total amount of rainfall between the locations. The estimator Sen’s slope has been calculated for the five decadal periods showing rising slope magnitude in some locations. In (1996-2005) decadal period, Kauru Sen’s revealed 113.33, Kaduna North 58.889, Saminaka 52. In (1966-1975) decadal period, Kafanchan revealed 67.429. Some locations are shown rising insignificant decreasing trend magnitude. Decadal period of (1996-2005), Zaria revealed -55.33, Kafanchan -49.429. The decadal period of (2006-2015), Kaduna North shows -51.667, Kaduna South -51.875. These results were quite significant as the decades where Mann-Kendall has shown a negative trend, similar trends were observed for the Sen’s Slope and vice versa.