Comparative Analysis of Accuracy, Simplicity and Generality of Temperature-Based Global Solar Radiation Models: Application to the Solar Map of Asturias

The accuracy, complexity and generality of 13 temperature-based solar radiation models are compared using data measured during 2003–2016 at 21 weather stations in a large coastal area of northern Spain. The comparisons are based on dimensionless statistical indicators calculated for each model at each station, as well as on averages of errors calculated both for the group of eight stations located in the vicinity of the Principality of Asturias and for the set of all stations. Using site-calibrated coefficients, most models provide acceptable estimates, and no model outperforms the rest everywhere. The dispersion of the site-calibrated coefficients is analysed as a function of geographical variables, and general equations are obtained for each model, based on data from the group of eight stations. The results for the remaining stations allow the predictive capability of the models to be assessed in regions where radiometric measurements are not available. In general, models with a larger number of parameters perform worse, while a homogeneous single-parameter model achieves better results. Combined with GIS techniques, this model is used to update the Solar Map of Asturias, whose previous version was based on data from different time periods due to the scarcity of records at the time.