Regression Analysis of Solar Radiation and Sunshine Duration

Regression techniques have been used to investigate the correlations of monthly-average-daily and monthly-average-hourly global, direct and diffuse radiation with bright sunshine hours for Hong Kong. Measured data during the 15-year period from 1979 to 1993 have been used for this study. It has been found that the Angstrom-Prescott linear regression equation gives a good estimation of solar radiation based on measured sunshine data. It is suggested that regression equations developed for Hong Kong can be applied to other subtropical regions in Southern China, where measured solar radiation data are not available.