Dust storms are one of the most destructive and unique climatic phenomena that cause irreparable damage to cities, facilities, roads, etc. every year. This destructive phenomenon is affected by special weather conditions, which can be reduced and even dealt with if we know how dust storms and strong winds occur. The present study examines the trend of the number of dust days and its relationship with climatic parameters and vegetation, from 2005 to 2017 in the Yazd-Ardakan plain region. In the present study, the trend of changes in the number of dust days was eva‎luated through the Dust Storm Index (DSI). Then, in order to prepare maps of biogeomorphological types and normalized vegetation difference index (NDVI), the images of Landsat 7 and 8 satellites in the 13-year statistical period to the working units of the Upandaj plain, the plain covered, Citadel, arable lands, urban lands and NDVI layer in two classes (-1 – 0.15), (0.15 - 1) for Landsat 7 and Landsat 8 (-1 – 0.17), (0.17 - 1) satellite was classified in all studied areas and two areas of 10 and 20 km to the center of Yazd and Meybod stations. Also, in order to eva‎luate the accuracy of the type of work units created in the maps of biogeomorphological types, Kappa Cohen coefficient was calculated for each year. Then, the floor area was created for all levels of the region and the area, and also, climatic parameters including average annual temperature, average annual rainfall and average annual relative humidity were calculated. The relationship between dust storm index and climatic parameters and NDVI index was investigated using linear regression method. The results showed that the relationship between DSI index with units of Medium grain plain, Piedmont (Yazd region) and arable land is inverse but with the unit of citadel is direct. Also, urban land work unit had no effect on DSI index. In examining the relationship between DSI index and NDVI index, with the increase of dust storm index, the level of NDVI polygons for all levels decreased in the 13-year statistical period. The relationship between climatic parameters and DSI index is that by increasing the average annual temperature parameter and decreasing the two parameters of average annual rainfall and average annual relative humidity, the dust storm index increased for all three. Based on the findings of the present study, it can be concluded that the DSI index has an upward trend in the period under study, ie the number of dust days is increasing. Also, various factors such as climatic parameters, vegetation (NDVI index and working unit of biogeomorphological types map) and other working units of the mentioned maps (plain, plain-covered and citadel) have a significant effect on the index of round storms. And has dust.

10/2/2021 12:00:00 AM

553

NE102

پريسا كمالي اردكاني