Analysis of spatial and temporal variations of dust events in the South West of Iran

Dust storms have great significance for the physical environment and the world's human inhabitants. The southwest regions of Iran, due to dry environmental and climatic conditions have been identified as one of the five major regions in the world where dust storm generation is especially intense. In recent years, large parts of Iran have been affected by suspended particles from the dust storms that resulting in the closure of schools and governmental agencies as well as cancellation of aviation. The study area is located in the south west of Iran foothills of the Zagros Mountain Range just north of Persian Gulf. Dust and other meteorology data were prepared in three hours interval from 12 synoptic weather stations. Satellite images for tracking of dust storms have been prepared from 1 km „e 1 km resolution MODIS obtained from Terra. Also NCEP websites synoptic data and plots were used to determine atmospheric conditions during the occurrence of dust storms in the study area. According to statistical calculations, most storms occur in spring and summer atmospheric instability exists due to high surface temperatures. The lowest dust event occurred in fall and winter seasons in December and January when possibility of rainfall occurrence in the north and west of the region. Studies also show that the highest hourly dust phenomenon occurred in the afternoon hours in local time and the lowest time is occurred at 00UTC (3.5 local time), that it can be closely related to the heating surface and the occurrence of local dry instabilities. Surveys of data shows that dust in all the stations have two climactic peaks, one between1982-1990 and another for 2005-2008 periods. These peaks can be related to a variety of factors, including human factors such as war, agricultural activities, dam construction, and widespread droughts. Keywords: Air pollution, dust, the South West of Iran, natural hazards