Estimation of monthly Angström-Prescott equation coefficients from measured daily data in Toledo, Spain

Average RMSE and MBE for comparison between observed and estimated global radiation were 1.260 and −0.002 MJ m−2 day−1, respectively. The t-statistic was used as the best indicator, this indicator depends on both, and is more effective for determining the model performance. The agreement between the estimated and the measured data were remarkable and the method was recommended for use in Toledo (Spain).