Comparison and analysis of the temporal and spatial distribution of dust storms with visibility of fewer than 200 meters in western and southwestern Iran

Introduction Dust storms are one of the significant phenomena in the desert areas of the world. It is internationally agreed that days with visibility below 1000 metres due to dust present in the air are a result of strong winds. This atmospheric phenomenon causes damage or environmental, social and economic damage. Dust storms with visibility of fewer than 200 meters are the most severe storms that can occur in an area. Such storms disrupt the normal life of the residents and cause damage. In this research, the temporal and spatial distribution, as well as the occurrence of such storms in the two regions of southwest and west of Iran, have been investigated. Preliminary evidence indicates an increase in the frequency of these storms. On the other hand, these two regions are important regions of Iran in terms of agricultural and industrial production and population centers. The increase of such storms can cause serious damage to the economy, agriculture and health of the two population poles of the country. For analytical comparison of dust storms in Iran, two regions, 1- southwest including (Khuzestan, Kohkiluyeh and Boyer Ahmad and Chaharmahal and Bakhtiari provinces); 2- west including (Ilam, Kermanshah, Kurdistan, Hamedan and Lorestan provinces) it's been chosen. To select sample stations, after receiving dust data from all synoptic stations of 8 provinces from the Meteorological Organization, including (88 synoptic stations), the data were analyzed. According to the aim of the study, which was to investigate the trend of changes in the phenomenon of severe dust in the last three solar cycles (33-year statistical base), 28 stations of the above stations had the desired conditions. Then, the data with horizontal visibility less than 200 m were sorted. Frequency of dusty days in Excel environment; Extracted daily, monthly, seasonally and annually. SPSS software was used to investigate the traits and data scatter. Finally, from ArcGis10.6 software to draw maps, as follows; The topography of the area is shown as a zoning map and quantitative characteristics of dust events are displayed as a Bar / Column.