Estimation of sunshine duration using one-minute global irradiance measurements

In this paper, we have proposed a new model to estimate sunshine duration using one-minute global irradiance measurements. Preparing a software program upon the proposed model, in four different weather stations of Hamedan Airport, Anzali, Amol and Tuyserkan, we have computed the sunshine duration for different days of the year and compare the results with those obtained from the Campbell-Stokes sunshine recorder. Our results show that the mean value of differences between the estimated parameter and the real values of sunshine duration is 0.81 hours in Anzali station, 0.74 hours in Amol station, 0.5 hours in Hamedan Airport station and 0.3 hours in Tuyserkan station. Furthermore, the root-mean-square error (RMSE) obtained for different stations in this work varies between 0.154 to 0.875 h/day which is a good result compared with previous works. Comparing our results with those obtained in previous papers upon different proposed models indicates that our model can be a good alternative for the Campbell-Stokes sunshine recorder.