Table 4.

Nash–Sutcliffe efficiency (NSE) coefficients of the 13 empirical models for calculating ET_o,i at the monthly and annual timescales for Bangladesh. The bold values indicate the optimal model among other models.

ETo,i	ET0,1	ET0,2	ET0,3	ET0,4	ET0,5	ET0,6	ET0,7	ET0,8	ET0,9	ET0,10	ET0,11	ET0,12	ET0,13
Month/year
Jan	− 0.274	− 1.258	− 1.033	0.123	− 35.578	0.255	− 0.39	0.354	− 0.302	0.336	− 1.958	0.258	− 155.576
Feb	− 0.103	− 2.353	− 5.205	− 0.426	− 58.766	0.238	0.312	− 0.449	− 1.77	0.166	− 3.821	− 0.828	− 225.502
Mar	− 0.093	− 0.559	− 9.619	− 1.523	− 89.31	0.142	0.003	− 3.595	− 5.338	− 0.23	− 7.404	− 3.525	− 283.656
Apr	− 0.065	− 0.089	− 10.441	− 1.993	− 74.489	0.362	− 0.061	− 3.579	− 4.554	− 0.105	− 8.519	− 2.672	− 241.254
May	0.187	− 0.754	− 4.042	− 1.022	− 72.584	0.354	0.338	− 3.021	− 4.07	− 0.452	− 9.741	− 1.603	− 173.139
Jun	− 0.127	− 3.507	− 1.077	− 0.462	− 81.971	0.38	0.467	− 2.519	− 4.436	− 1.483	− 11.67	− 0.159	− 190.445
Jul	− 0.495	− 5.005	− 1.591	− 1.531	− 109.474	0.436	− 0.093	− 2.268	− 4.824	− 3.206	− 17.811	0.422	− 190.097
Aug	− 0.233	− 2.778	− 4.285	− 2.871	− 121.219	0.351	− 0.03	− 2.678	− 5.35	− 3.301	− 20.738	0.263	− 203.639
Sep	− 0.415	− 2.248	− 7.579	− 3.418	− 124.944	0.419	− 0.781	− 1.972	− 4.612	− 3.229	− 23.887	0.48	− 271.754
Oct	− 0.481	− 0.762	− 9.322	− 3.902	− 119.488	− 0.355	− 1.729	− 0.846	− 2.843	− 2.18	− 26.957	0.439	− 219.231
Nov	− 0.309	− 1.496	− 7.088	− 1.192	− 82.924	− 0.672	− 2.958	0.103	− 0.97	− 0.236	− 16.758	0.266	− 273.802
Dec	− 0.371	− 1.721	− 0.683	0.106	− 42.958	0.047	− 1.95	0.255	− 0.226	0.281	− 5.249	0.311	− 141.118
Year	− 0.477	− 4.116	− 25.07	− 3.474	− 211.012	0.176	− 0.341	− 4.411	− 8.788	− 1.498	− 28.244	− 1.667	− 1030.942