Calculating the diffuse solar radiation in regions without solar radiation measurements

Correlations for calculating diffuse solar radiation can be classified into models with global solar radiation (H-based method) and without it (Non-H method). The objective of the present study is to compare the performance of H-based and Non-H methods for calculating the diffuse solar radiation in regions without solar radiation measurements. The comparison is carried out at eight meteorological stations in China focusing on the monthly average daily diffuse solar radiation. Based on statistical error tests, the results show that the Non-H method that includes other readily available meteorological elements gives better estimates. Therefore, it can be concluded that the Non-H method is more appropriate than the H-based one for calculating the diffuse solar radiation in regions without solar radiation measurements.

► Methods for calculating diffuse solar radiation in regions without solar radiation measurements are investigated.
► Diffuse solar radiation models can be classified into two groups according to global solar radiation.
► Two approaches are compared at the eight meteorological stations in China.
►  The method without global solar radiation is recommended.