Revealing the role of changes in vegetation cover and soil moisture in the annual distribution of dust events in Khuzestan province

Dust events are one of the most important and challenging environmental and climatic hazards of the whole country and especially of Khuzestan province. The main goal of this research is to reveal the role of changes in vegetation cover and soil moisture in the annual distribution of dust events in Khuzestan province. In this regard, 3 categories of data were used. The data related to station dust codes obtained during the statistical period of 2010-2020 for the synoptic stations of Khuzestan province on an hourly scale. The second set of monthly vegetation data was obtained from the NDVI product (MOD13C3) of the MODIS sensor, and finally, the moisture data of the upper 5 cm layer of the soil was provided from the SMAP sensor on a monthly basis. By analyzing the frequency of dust codes, the monthly frequency of dust events, the concentration and persistence of dust were investigated. By obtaining the spatial average values of the two moisture indices of the upper 5 cm soil layer and the monthly NDVI index, the correlation and relationship between the dust indices and these indices was analyzed. The results showed that based on the average period of 2010-2020, the period of 4 months from May to August is the dust peak period in the province. There are at least 11 days of dust in every month, and the concentration of dust is more than 2800 micrograms per cubic meter in the air, and the duration of the dust event in the province is at least 40 hours. The investigation of the moisture indicators of the upper layer of the soil and vegetation showed that, exactly in the province during the same dust peak period, the soil moisture of the upper layer of the soil reached less than 10% in a large part of the central and southern regions of the province, and at the same time, the vegetation index also In these sectors, it has reached less than 0.18. In addition, in this research, it was observed that the monthly changes in the moisture content of the upper 5 cm layer of the soil with a correlation coefficient of -0.88 have the greatest effect on controlling the dust concentration in Khuzestan province.