Identification of dust source area in Sistan basin and determination of their characteristics

Sistan watershed has caused severe dust storms in the region in recent years due to the drying up of Lake Hamoon and consecutive droughts. This study aimed to identify and determine the characteristics of dust source areas (land use, lithology, slope, and geomorphology) in the Sistan watershed. To identify the dust source area, MODIS satellite images of dust days for the period 2015 to 2019 were used using dust detection indicators including BTD3132, BTD2931, NDDI, and D. The results of identifying dust source area indicate that a total of 211 dust source areas were identified in the whole region. Of these identified dust source area, 61 are in Iran and 150 in Afghanistan. The results of the distribution of dust collection centers in different uses indicate that dryland agricultural lands with 172 centers, dried lake surfaces, and irrigated agricultural lands with 16 and 12 sources have the highest dust collection sources. From the overlap of the lithology map and dust source, it was obtained that the most dust source area with 111 and 98 sources, respectively, are located in continuous and discontinuous sedimentary formations. The results of the distribution of dust source area in geomorphological units indicate that the erosion plain unit with an area of 35.69 percent, 48 dust source area has the highest collection source. Also, the results of the distribution of dust source area in different slopes show that the highest dust source area is in the slopes of 0 to 2% with 107 sources and the lowest located in more slopes of 32%% with 6 sources.