Impact of Sea Surface Temperature over East Mole and South Atlantic Ocean on Rainfall Pattern over the Coastal Stations of Nigeria

Abstract

Aim: This study examines the impacts of South Atlantic and East mole Sea Surface Temperatures on rainfall in some selected coastal stations in Nigeria. This study seeks to investigate the relationship between SST and rainfall in some of the coastal stations of Nigeria, also to find the correlation between rainfall and SST’s of east mole and south Atlantic and to develop statistical model to estimate monthly/seasonal rainfall over the selected station using January, February and December SST of east mole and south Atlantic ocean. Study Design: Sea surface temperature (SST) and rainfall data were used for this study. The SST for east mole covers 17 years spanning between 1990 and 2007 and rainfall data for 30 years (1979-2007) were collected from the Nigerian Meteorological Agency Oshodi, Lagos (NIMET). South Atlantic SST (0-20ºSouth, 30ºWest-10ºEast) was obtained from the National Weather Service, Climate Prediction Center (NOAA) for 59 years from 1950-2008. Place and Duration of Study: The stations are Lagos, Benin, Calabar and Portharcourt. Methodology: Statistical analysis which includes (Mean, standard deviation, trend analysis and correlation analysis) were carried out. SPSS and statistica softwares were used to carry out the analysis. The rainfall and SST were standardized. Results: The result showed that rainfall in Lagos can be predicted for the early period April-June, mid period of June-September and the entire raining season April-October using east mole SST data for dry months of November, December and January. The trends of SST were found to be increasing in South Atlantic Ocean, so also was rainfall in all the coastal stations. Some ENSO years also affected rainfall as it reduces rainfall drastically far below normal in the coast, Nigerian coastal waters were observed to be warmest in April and coldest in August. Conclusion: The trends of SST and rainfall were found to be increasing within the study period. The correlation of SST and rainfall was 0.64 for (Jun-Sept) and 0.59 for (APR-OCT) in Lagos. The correlation was found to be 0.44 For Portharcourt.