ABSTRACT

Rainfall is very important for the economic growth and development of any nation; hence there is dire need to study the annual trends. This study examined the trends and patterns in the rainfall of selected locations in Southern Nigeria. Rainfall data (1983-2012) for ten (10) locations were used for this study. Statistical techniques like mean, standard deviation, coefficient of skewness, coefficient of kurtosis, coefficient of variation and standardized anomaly index were employed to analyze the data and depict the distribution of rainfall in these stations. The mean annual rainfall ranging from 1349.72mm (Ibadan) to 2825.82mm (Warn) indicated a wide variation from one station to the other stations. Also, maximum annual rainfall occurred at Warri station (4489.80mm) in the year 2008 and the minimum occurred at Benin (229. 1 0mm) in 2005. Moreover, it was found that Benin station had the highest variability with a coefficient of variability 26.37% and Port Harcourt station had the minimum variability with a coefficient of variability 11 .68%. The results of the linear trend lines revealed an increase in rainfall supply over the period of study in eight (8) locations and the other remaining locations (Owerri and Umuahia) had a decrease in the trend. However, the patterns of rainfall in these areas are random or fluctuating. It was recommended that models built on the perceived decreasing rainfall, such as drainages, dams, have to be reviewed. Also opportunities should he provided by the government for professionals to study and develop realistic methods for utilization of surplus water.