Assessment of global solar radiation estimates across different regions of Togo, West Africa

This study, for the first time, adopts 20 simple empirical models to estimate daily global solar radiation (GSR) in selected meteorological stations in Togo, West Africa with a view to evaluating the performance of the models in predicting GSR over different climatic zones in the region. It used 3-year (1990–1992) daily mean ground station data obtained from the Togo Meteorological Agency for the models’ calibration at Lomé station to validate daily models’ simulations at other stations (Atakpamé, Sokodé, Kara and Mango). Models’ evaluation and ranking were done using performance indices such as root-mean-square error ( RMSE ), mean error ( ME ), percentage mean error ( PME ), Nash–Sutcliffe coefficient ( NSE ), and correlation coefficient ( r ). Our results suggested relatively low and insignificant negative biases (|PME|