ANALYSIS OF TRENDS IN MONTHLY RAINFALL PROFILE FOR KATSINA, KATSINA STATE (1946-2006).

Y.G. Hassan and A.I. Abdulhamed

This study examines the trends in annual totals and pattern in monthly distribution of rainfall in Katsina lat. 12⁰03- N Long 08⁰32`N. Daily records of rainfall over a period of 60 years(1946-2006) were used. The annual and the monthly rainfall data were subjected to normality test using Fisher’s standardized co-efficient of Skewness (Z1) and Kurtosis (Z2). The result shows that over 85% of the data conform to the Gaussian normal distribution at 95% significant confidence limit. A linear regression technique was used to determine trend in both monthly and annual distribution. To further determine the trend, ten years and five years running mean were also used. The results show that, all the rainy months under study conform to the annual rainfall trends which started to decline in the 1960’s. Monthly rainfall value shows an abrupt and frequent extreme variability between years with the exception of August. However, sometimes increase in monthly values reduces the frequency and intensity of such occurrence. This extreme variability is often described as catastrophic to crops at all stages of development.

Key words: Rainfall, Annual, Monthly ,Skewness, Trends.