Geographical Research

In this study, a number of 95 synoptic stations of the country were extracted in a statistical period (1990-2007) in order to identify fog-prone areas and dust storms with vision less than one kilometer along with the dust. Then, frequency map of the event, with vision less than one kilometer was provided by Spline method in roads network in Arc GIS environment. Also, air cloudy percentage map at land surface and optional thickness of clouds with less height and stratus clouds with low height has been presented in roads of the country for a statistical period (1980-2010) using spectrum analysis of infrared and visible bands measured with SEVERI from MSG satellite. In the same direction, MODIS satellite data and Aerosol Optical Thickness (AOT) is used for statistical period (2000-2010) for extraction of spatial distribution of dust storms. With due observance to the results, maximum percentage of frequency of event with capability of vision less than one kilometer is related to the fog in Caspian and northwest area of the country. In addition, maximum percentage of frequency of event with vision capability, less than one kilometer, is related to the dust in southwest and southeast part of the country.The maximum degree of risk in terms of fog-prone area in roads network of the country is related to the south and southwest area of the Caspian region while the maximum degree of risk in terms of dust-prone area is related to the west to south part of the country (northeast part of Caspian area).