Trend analysis of rainfall in three cities in Nigeria as determinant of climate change

Abstract

Changes observed in rainfall trend or distribution can be attributed to climate change and variability. This study aimed at determining the rainfall trends of three cities in Nigeria representing different vegetation zones namely; Sokoto (Sahel savanna), Abuja (Guinea savanna) and Port Harcourt (mangrove rainforest). The rainfall data was collected from Nigeria Meteorological Agency (NIMET) covering a period of 39 years (1985 to 2023). The data was analyzed using Mann Kendall Test. The results obtained showed no trend in rainfall in all the cities. It also reveals an increasing rainfall in Sokoto and Port Harcourt whereas decrease in Abuja with no statistically significant trend (P = 0.27, 0.65 and 0.06 and Kendall Tau = 0.126, -0.053 and 0.215 for Sokoto, Abuja and Port Harcourt respectively). A mean rainfall values of 656.1mm, 1510.1mm and 2928.4mm were also obtained for Sokoto, Abuja and Port Harcourt respectively. This study therefore reveals though rainfall pattern increases in two of the cities and decreases in one, there is no statistically significant trend in the rainfall. The rainfall pattern could predispose the study areas to extreme weather events like flooding and drought. It is recommended that adequate weather and climate information should be made available alongside urgent need for more weather observations for planning in sectors of water resource management to prevent excessive rainfall from becoming disasters.