Detection of cloud types using satellite data based on ISCCP Algorithm over Iran

In this paper, in order to detection of cloud types over Iran, NOAA satellite data and of cloud recognition Algorithm of International Satellite Cloud Climatology Project (ISCCP) have been applied. Firstly, monthly mean of optical cloud depth and cloud top pressure have been derived from AVHRR sensor related to NOAA satellite during (1981-2010) for 12 months (January -December). Secondly, coverage of 9 cloud types including Cumulus (Cu), Altocumulus(Ac), Altostratus(As), Stratocumulus(Sc), Deep Convection(Cb), Stratus(St), Nimbostratus(Ns), Cirrus(Ci), and Cirrostratus(Cs) have been identified over Iran using ISCCP Algorithm. The method is innovative and has been used for the first time in Iran. The remarkable results of cloud detection in different months for Iran showed that maximum of frequency percent of Cu clouds occur in Oct., Nov., Dec., Jan., and Feb. over southern and Southeast of coast of Iran. As clouds have high frequency over all months but its distribution is different in various months. Frequency of As clouds is more than 50% over vast area and its maximum exceeds than 80% in all months. Sc clouds also have similar distribution in Autumn and winter seasons including Sep., Oct., Nov., Dec., Jan., and Feb. In contrast, frequency of St clouds are very low for all months except July which the Frequency is 5%-25% in Southwest of Caspian Sea. Percent of frequency of Cs clouds have high difference in different months. The most frequency of this cloud occurs in Jan., Feb., and Oct. In these months the maximum of frequency exceeds more than 50%.