A hybrid model for estimating global solar radiation

In view of the site-dependence of Ångström correlation, this study developed a hybrid model to estimate global radiation H. Unlike Ångström correlation H=(α+βS/S₀)H₀, this model suggested that H=(a+b S/S₀)H_b+(c+d S/S₀)H_d, H_b and H_d are effective beam radiation and effective diffuse radiation, which imply latitude, elevation and seasonal effect on radiation. H_b and H_d are calculated by an arithmetic model derived from spectral model. The hybrid model was designed for estimating monthly mean daily global radiation with hourly-recorded bright sunshine time, and its applicability was verified at observatories in Japan.