Spatio-temporal analysis of seasonal and annual trends of dust storm days in arid climates of Iran

Dust storm (DS) is a harmful climatic phenomenon that causes damage to the environment and agriculture. The aim of this study was to investigate the trend analysis of seasonal and annual changes of DS during climatic period of 1977-2021 in arid climates of Iran in 42 synoptic stations. First, the long term changes of DS, before and after 2005 were compared togeather and investigated. Then, time series trend analysis was performed using regression method and spatial analysis by Menn-Kendall and Sen`s Slope methods. The results showed an increase of DS after 2005. The trend of time series also showed an increasing trend in most climates and stations, with the most intense increasing slope during the periods of 2005-2010 and after 2011. The results showed that the frequency of stations with a significant increasing trend in the semi-arid climates on a seasonal and annual basis were up to 93 and 64; and in arid climates up to 83 and 83 percent of the stations, respectively. On the other hand, the incremental changes of 45-year DS in the extra arid climate in winter, spring, summer, autumn and whole year were up to 68, 69, 68, 55 and 261 days; in arid climate up to 54, 31, 37, 45 and 187 days; and in semi-arid climate has reached 23, 21, 9, 12 and 58 days, respectively. Therefore, the temporal change of DS is towards the winter and spring seasons, which indicates the spread of this phenomenon to the wet seasons.