Comparison of Sea Surface Temperature over The Gulf of Guinea during Dry and Wet Year Composites of West Africa

This study investigates the relationship between sea surface temperature (SST) in the Gulf of Guinea and precipitation variability over West Africa during dry and wet year composites (1981-2020). Using ERA-5 reanalysis SST data and CRU TS V4 rainfall records, the study identifies dry years (1983, 1984, 1987, 1990) and wet years (1999, 2003, 2010, 2019) through Standardized Precipitation Index (SPI) and rainfall anomaly analysis. Results reveal a strong negative monthly SST-precipitation correlation (R = -0.78) and a moderate positive annual correlation (R = 0.54), indicating that Gulf of Guinea SST plays a pivotal role in modulating West African monsoon intensity. Spatial analysis shows that SST is consistently higher during wet years at all months and latitudinal positions, with steeper temperature gradients toward the West African coast driven by the Benguela Current. The findings have direct implications for seasonal climate forecasting, agricultural planning, and water resource management across West Africa.