An Investigation into the Nature and Variability of Climate Change Induced Rainfall Over Awka, Anambra State

ABSTRACT

This thesis investigates the nature and variability of climate change-induced rainfall over Awka, Anambra state. Time series of annual rainfall for Awka, Anambra state was analysed to reveal shifts in rainfall pattern occasioned by ongoing climate change. Past rainfall data over four decades (1975-2014) were collected for the study area for analysis. The series exhibited shifts in bimodal rainfall pattern during annual analysis, however, decadal analysis showed no significant shift. The least rainfall years were 1975 followed by 1983 at average values of 116.4mm and 116.9mm respectively, while the wettest years were 1995 followed by 2009 at average values 206.5mm and 179.8mm respectively, showing that the most recent decades experience higher rainfall, also exceeding the mean of the total mean annual rainfall at 153.8mm. The months of onset and retreat of rainy season was March and October, however, significant rainfall months were April May, June, July, August, September and October. The little dry season/August break experienced shifts in the annual analysis but had no significant shift in the decadal analysis. The total average annual rainfall occurrence throughout the study period is 6150.8mm. The study concludes that variability observed for West Africa rainfall, Awka inclusive has not recently resulted in significant shifts, rather fluctuations in Awka, Anambra state.