Analysis of Trend Dust Index Changes (DSI) and Evaluation of its Relationship with Drought in the southern slope of Alborz

One of the Factors affecting on the trend of changes in dust phenomenon, is the fluctuations of climatic parameters and consequently drought. The purpose of this study was to investigate the trend of changes in Dust Index (DSI) and its relationship with drought indices (SPI and SPEI) in the southern range of Alborz. After of receiving the meteorological codes, seasonally-annually ten years DSI was calculated and zoned. Then standardized monthly DSI, SPI and SPEI stations with thirty-year period and assessment DSI temporal changes trends, using of Man Kendall and Petit statistical methods and finally, its correlation with SPI and SPEI was performed by Pearson method. The results showed that from west to east, increased the intensity of the dust and in spring was observed with maximum intensity. Annual changes of The DSI (2017-2008) are irregular and do not have a trend, as in 2008, the intensity of dust high and the next year sensible a decline, similar to 2016 and 2017 seen. Also the trend of DSI time changes showed that the west and central stations had a significant trend and as we move eastward the temporal changes were irregular and without significant trend. On the other hand, there was no significant correlation between DSI and SPI indices and there was a negative relationship between DSI and SPEI except for the western part of the region which in some stations is high-intensity, this significant relationship, and with standardization, this relationship becomes even more evident. In general, considering precipitation with temperature and evapotranspiration has shown a better correlation with the dust index, as well as changes in socioeconomic factors as an influential factor on dust should be discussed and examined.