ASSESSMENT OF CLIMATE VARIABILITY IN SOUTHWESTERN NIGERIA USING RAINFALL TRENDS

Abstract

This study was carried out in the Southwestern region of Nigeria. Its main aim was to assess the Climate scenario in the area using prevailing rainfall trends. Rainfall records for 35years (1975 - 2010) were obtained from the Nigerian Meteorological station (NIMET) at its headquarters in Oshodi, Lagos. The data were obtained for five stations which are Ikeja, Abeokuta, Akure, Ibadan and Osogbo. These data were analyzed in order to obtain the rainfall trend and consequently the climate variability/change scenario. The Simple linear regression analysis and the Runs test were used to identify the trends in rainfall for each of the stations and the whole region. The t-test and correlation analysis were also employed in determining the significance and strength of the trend gotten. Microsoft excel and SPSS were both used to “run” the analyses. The results obtained showed an increasing trend in rainfall for all the stations. However, this trend was found to be insignificant for four of the five stations. Only Abeokuta showed statistical significance in its rainfall trend. It had the largest rate of increase in rainfall with 9.106mm/year for the 35 years period. For the whole Southwestern region, a weak insignificant trend in rainfall was found although there was increasing rainfall in the region with an average rate of 5.250mm/year. The study concluded that The minimal climate variability scenario in this part of the country will intensify with time and recommends combating, controlling and mitigating the climate change propelled rainfall extremes, floods and drought through systematic use of climate information in planning and decision making at all levels, use of climate-informed technologies that reduce vulnerability to weather variability and uncertainty, as well as climate-informed policy and market-based interventions that transfer risk from vulnerable populations.