Characteristic distribution of global solar radiation for Amman, Jordan

Hourly global solar radiation data measured on a horizontal surface in Amman, Jordan, available for the period 1983–1987, have been studied and analysed. Average values of daily, monthly and yearly global radiation, as well as maximum and minimum radiation values, were determined. The average monthly mean daily global radiation ranged from 8.001 to 2.653 kWh m⁻² per day. Over the 1983–1987 period, the annual daily mean of global radiation was 5.302 kWh m⁻² per day. The maximum monthly mean daily global radiation varied between 8.295 and 3.611 kWh m⁻² per day whereas that of the minimum monthly mean daily radiation varied between 7.590 and 1.680 kWh m⁻² per day. The calculated monthly mean daily global solar radiation data were employed to develop linear correlations between the sunshine hours and each of the average, maximum and minimum global radiation for Amman, using regression technique. The accuracy of the derived correlations was tested using measured radiation data for Amman. The results show that the developed correlations are adequate to predict monthly mean daily global radiation within a maximum error ranging between 6.6 and 9.6%. The average error incurred in predicting global radiation does not exceed 0.3%.