Investigating the impact of drought on dust events in Kerman province using meteorological and satellite data

In recent years, the dust events frequency and the drought severity have increased in many arid regions of Iran, so it is very important to discover the relationship between these two phenomena in these regions. In the present study, the drought situation of Kerman province using the standardized precipitation-evaporation index (SPEI) and the frequency of dust events using codes 07, 08, 09, 35-30 and 98 recorded in synoptic stations during 1990-2018 has been investigated. In addition, Palmer Drought Severity Index (PDSI) and Aerosol Optical Depth (AOD) were also used to confirm the results obtained from meteorological data. The trends of changes in drought indices, dust occurrences and AOD were analyzed using the Mann-Kendall test and their correlation with each other was analyzed using the Pearson correlation coefficient. The results showed that Kerman faced the most severe drought events in the period from 1998 to 2010, and the longest drought with a duration of 21 years and an intensity of 11.84 occurred in the northwest of the province. The temporal analysis of dust events showed that intensification of their activity in the spring and winter seasons, especially in the months of March, April and May. The results of the analysis of SPEI changes showed that the drought in Kerman had an increasing and significant trend, while the trend of changes in the frequency of dust occurrences had a decreasing and insignificant trend. Analysis of changes using satellite data also proved the significant increasing trend of PDSI and non-significant decreasing trend of AOD, especially in hot seasons. Correlation analysis between SPEI and dust events showed that the intensification of dry conditions in November had a significant effect on the intensification of dust events in Kerman province (r = -0.46; P-value<0.05), while in other months, it has no significant effect on the dust events frequency. The results of PDSI and AOD confirmed the weak correlation between these two phenomena in Kerman province. The results also showed that the effect of drought time delays on the dust phenomenon in this province was weak and insignificant.