Estimating daily global solar radiation by day of the year in six cities located in the Yucatán Peninsula, Mexico

Prediction of daily global solar radiation by using day of the year is particularly attractive because this parameter is not dependent on the input of meteorological parameters. In this study, four existing day of the year-based (DYB) models were evaluated and a new empirical DYB model was developed for estimating daily global solar radiation on a horizontal surface for six automatic weather stations of Yucatán Peninsula, Mexico. The performance of the models was assessed with root mean squared error (RMSE), mean bias error (MBE), mean percentage error (MPE), mean absolute percentage error (MAPE), mean absolute bias error (MABE) and coefficient of determination (R2). The results show that the new proposed Gaussian DYB model estimates daily solar radiation better than other DYB models. Furthermore, a seasonal analysis shows that the model has good performance in all seasons, including in the rainy season. The results also suggest that the new model can be useful for highly variable climate conditions