Calculation of sky turbidity in the Kingdom of Saudi Arabia

The atmospheric turbidity has been calculated and averaged for 29 places around the Kingdom of Saudi Arabia by 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 overall 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 0.474±0.090 in Riyadh. The low value of the turbidity indicates that the sky of Sirr-Lasan (2100 meter above sea level) may be the clearest sky in the country if the turbidity is taken to be the main factor in preliminary site selection for astronomical observatory. Correlations between the turbidity and geographical coordinates have been investigated 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 Saudi Arabian sky has relatively small disturbance in the atmosphere.