Abstract: | Study of the climatology of global solar radiation is considered very useful for assessing the potential efficiency of systems designed for solar energy utilization. This paper explores some aspects of solar radiation climatology in Iraq. Analysis of the monthly averages global solar radiation and the general atmospheric transparency for the period 1971–1985 for three different climatological zones (Mosul, Baghdad, Nasiriyah) are discussed. The frequency distribution of daily clearness index for each station is determined using histograms of frequencies. The percentage number of days with solar radiation and sunshine duration values below a certain value is analyzed and discussed. The period of successive days having radiation less than 5 MJ/m2 · day−1 and 10 MJ/m2 · day−1 is examined and presented graphically. |