Again, as for the ordinary kriging, a seasonal pattern is present, with the summer months showing the lowest RMSE values and the winter months the highest ones. Particularly, lowest RMSE relative value are found for February 0.54 MJ m-2day-1 (4.5%) and the highest for October 1.31 MJ m-2day-1 (10.2 %). MAE ranges from 0.22 MJ m-2day-1 (2.2%) in January to 0.70 MJ m-2day-1 (5.4%) in October. Regarding the ME, the model tends to slightly overestimate the solar radiation, for all the months, but ME values are fairly low. Figure 4 shows the estimated H maps based on the residual kriging procedure.