ESTIMATION OF HOURLY GLOBAL AND DIFFUSE SOLAR-RADIATION FROM HOURLY SUNSHINE DURATION

A statistical procedure has been employed to develop correlations of monthly-mean-hourly global and diffuse solar radiation on a horizontal surface to hourly sunshine duration. Several years of measured data on solar radiation and sunshine duration, reported in the literature for two stations in the southern African region, is employed for this purpose. The applicability of the developed correlations is tested by estimating solar radiation for a new location. The excellent agreement between the measured and estimated data for that station suggest the wide applicability of the method.