In view of the site-dependence of Angstrom correlation, this study developed a hybrid model to estimate global radiation H. Unlike Angstrom correlation H = (alpha + betaS/S-0)H-0, this model suggested that H = (a + b S/S-0)H-b + (c + d S/S-0)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. (C) 2001 Elsevier Science Ltd. All rights reserved.