Calculation of direct solar and diffuse radiation in

This study deals with the calculation of direct solar radiation and diffuse radiation for locations in Israel as hourly values. The model is based on the calculation of the Linke turbidity factors for the stations Bet-Dagan, Jerusalem, Beer Sheva, Sedom and Eilat, which have been determined from radiation measurements. The turbidity factors for clear sky conditions showed a characteristic yearly pattern and the differences between the stations were related to their geographical locations. The model requires different algorithms for calculations in the Rift Valley system and the rest of Israel. The calculations proved to be very accurate for clear sky conditions with high radiation values (average deviation: 7.3 % or 61.6 W/m2 for values above 600 W/m2). The presence of clouds and lower sun angles lead to less accurate results, which are nevertheless still acceptable within the range for further applications. Copyright © 2001 Royal Meteorological Society