The Synoptic Analysis of Seasonal Changes in the Frequency of Foggy Days: A Case Study of Southern Regions of Iran

Fog is a climatic phenomenon which has beneficial and harmful effects in human life. Tow first purposes of present study are determining of temporal and spatial differences of the Frequencies of Foggy Days (FFD) in Southern Iran. For achieve first purpose (testing of first study hypothesis)، was prepared and fixed daily and monthly data of foggy days for 40 synoptic stations during 10 years interval (1996-2005). Determining of monthly، seasonal، periodic and annual averages of frequencies of FFD in studying cities were the first results of this study. These results showed that maximum monthly frequency of FFD was occurred in western land during cold season and maximum frequency of FFD was happened in eastern land during warm one. Final results indicated that the increasing of the frequency of FFD has been accompanied with approaching of high pressure systems and ridges at sea and 500 Hpa height level، respectively in western land (iranian coasts of Persian Gulf). Also، this increasing was simultaneously occurred with approaching of low pressure systems of Hijaz and Pakistan and high pressure systems of Oman sea in eastern land (iranian coasts of Oman sea).