Calculation of Sky Turbidity in the Kingdom of Saudi Arabia

Abstract

The atmospheric turbidity has been calculated using data from 29 locations around the Kingdom of Saudi Arabia, using a nine years solar radiation data covering the period from 1971 to 1980. The turbidity values were found to range from 0.1 to 0.4, and the long-term average of the turbidity was 0.281±0.056. The minimum value was in Sirr-Lasan (0.168±0.028) and the maximum value was in Riyadh 0.474±0.090. The low value of the turbidity indicates that the sky of Sirr-Lasan (2100 meter above sea level) may be the clearest in the country, when considering the turbidity as the main factor in preliminary site selection for astronomical observatory. Correlations between the turbidity and geographical coordinates have been investigated here, and have shown a weak relation between them. Also, seasonal variations studies have shown no significant distribution, which means that each station has its own trend. The low values of the turbidity indicate that the sky of Saudi Arabia has relatively slight polluted atmosphere in the period of study.