“…Eight different performance indices (Equations (3)–(10)), namely the determination coefficient (R 2 ), the performance index (PI), the variance account factor (VAF), Willmott’s index of agreement (WI), the root mean square error (RMSE), the mean absolute error (MAE), the RMSE observation standard deviation ratio (RSR) and the weighted mean absolute percentage error (WMAPE), were determined to evaluate the performance of the developed models [ 38 , 44 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 ]. For a flawless prediction model, the values of these indices should be identical to their ideal values, as shown in Table 2 .…”