ASSESSMENT OF PRECIPITATION CHANGES USING MULTIPLE GENERAL CIRCULATION MODELS OVER THE GAMBIA

This study employed 31 years of monthly historical precipitation data (1985–2015) from fifteen meteorological stations in The Gambia. A collection of GCMs was statistically downscaled to replicate the referenced precipitation, and the models' efficacy in capturing and reproducing the baseline precipitation was assessed using statistical metrics of RMSE, CORR, R², and MAE. The selected general circulation models accurately replicate both monthly and annual baseline precipitation, exhibiting a high degree of confidence and a suitable representation of the specified precipitation events. The study indicates that precipitation projections across all regions under the RCPs for all GCMs demonstrate variable levels of reduction. CanES-M5 forecasts the most substantial reduction in annual mean precipitation, with declines of 36.2% and 39.2% in the West Coast Region (WCR), while the MPI model anticipates the minimal decrease of 4.8% and 9.5% in Banjul during the mid-century period (2030-2060) relative to the reference period (1985-2015) for RCP 4.5 and RCP 8.5. The projected decline in precipitation will likely increase the aridity situation in the Gambia, which could lead to an intensive drought and thus result in low food production and the accessibility of safe drinking water