Investigating the Relationship between Drought and Trend of the Frequency of Dust Storms in the West and Southwest of Iran

Today, the occurrence of dust storms, in addition to having a direct impact on people's lives, has adversely affected the agricultural sector, including agronomy, horticulture, natural resources and the environment. This study was carried out to investigate the trend of frequency changes of days with dust storms and its relationship with Standardized Precipitation Index (SPI), using hourly and daily dust data and monthly rainfall data of 21 selected synoptic station in the west and southwest of the country with a seasonal scale over a 25 years (1990-2014) statistical period. After quality controlling all dust data for abnormality, using Kolmogorov-Smirnov test, and also measuring the long-term memory of time series using the Hurst coefficient, non-parametric Mann-Kendall and Spearman tests were used at a 95% confidence level to examine the trend of abnormal data. Then, the seasonal SPI drought index was calculated in the proposed stations and its trend was analyzed by parametric linear regression test method. Also, the zoning of the Mann-Kendall statistics and the linear regression of the variables were performed by IDW method in ArcGIS software. Then, to investigate the climatic relationship with dust storms, stations with SPI index and also variable frequency of days associated with dust storms had a significant trend (dust storms in both Mann-Kendall and Spearman methods and SPI index in the method of linear regression), were analyzed by Pearson correlation technique. The results showed that out of a total 21 series of seasonal data; the stations of Hamedan (Nozheh), Ilam, Islamabade-Gharb, Keramnshah, Sarpole-Zahab, Abadan, Bandare-Mahshahr, Bostan, Dezful, Masjedsoleyman, Safiabad, Dogonbadan, Sanandaj, and Khorramabad have a high correlation between standard precipitation climatic index and the frequency of dusty days. So that the highest correlation between the number of dusty days and SPI drought index was attributed to Dezful, Bostan and Masjedsoleyman stations with the Pearson coefficients of -0.920, -0.913 and -0.911 and P-Values of 0.002, 0.025 and 0.044, respectively. The results of this study could be useful in managing the consequences of dust storms in the study areas.