Investigating the trend of dust storms by DSI anomaly in southeast Iran and its relationship with the NDVI index

Dust storms are natural phenomena but with serious and destructive effects on the environment and human societies. The southeast region of Iran is one of the most active sources of dust storms in Asia, dust storms occur in this region almost all year round, but their frequency is higher in summer and spring. This study aims to investigate the dust storm anomaly in the southeast of Iran during a period of 21 years (2000-2020) and its relationship with vegetation anomaly changes. The DSIA was used to examine the spatial and temporal changes of dust storms, and the NDVIA was used to examine the changes in vegetation anomalies in the region. The correlation between DSIA and NDVIA was determined by using Pearson's coefficient. The temporal trends of DSIA show that from 2000 to 2012, it had a positive and increasing trend in most of the years of the study, and the highest value of DSIA occurred in 2012, which is equal to 96%. Then, from 2012 to 2020, this trend has been decreasing, and the lowest value of DSIA equal to -67% was observed in 2020. Also, moving from east to west of the studied area, the value of the DSIA decreased. The temporal trends of the NDVIA show that from 2000 to 2012, the trend of changes is downward, but from 2012 to 2020, the trend of changes is upward. In terms of time, the highest value of the NDVIA index is related to 2014, and in general, since 2012, this index has had positive and increasing changes. Pearson correlation results showed that the DSIA index is significantly correlated with the NDVI index, this correlation is negative (p-value<0.05 r=0.52) due to the negative and significant correlation between the NDVIA index and the DSIA index. Since 2012, with the increase of the NDVIA index and the improvement of vegetation conditions, the DSIA index has decreased. The effect of this correlation was also observed spatially, as moving from east to west of the region, with the increase of the NDVIA index, the amount of DSIA decreases. These results can be useful for decision-makers to assess the risks of dust storm impacts and reduce its negative consequences in the southeast parts of Iran.