Estimating total incoming solar radiation on the earth surface of Isfahan



        Abstract   In this research,we used daily incoming solar radiation data of Isfahan ozone station during 1365-1387 to find an estimation model of Incoming solar radiation using sunshine ours.The results have been compared to the other common models using RMSE and MBE indices. The results show that the regression amount of our model is 0.91 and 0.6 and 0.7 for the models Frere and McCulloc respectively .Also ,our model has a very precise results for May and Augest months in which the error is less than -2 %.