Assessment of soil moisture using remote sensing ECV Database and its correlation with dust events - South and West of Iran

Surface soil moisture is a key variable in hydrological, meteorological and environmental studies and one of the important and effective parameters in the occurrence of dust. The purpose of this paper is in two folds, the first to validate the soil moisture of ECV database and the second investigate the effect of soil moisture on occurrence dust. The first purpose of this study was to evaluate the relationship between estimated surface soil moisture of remote sensing ECV databases and observed surface soil moisture of agricultural meteorological stations located in the south and west of Iran in Khuzestan, Ilam, Kohgiluyeh and Boyer-Ahmad, Lorestan and Chaharmahal-Bakhtiari provinces.  For this purpose, statistical indicators such as Pearson correlation coefficient, mean absolute error, mean oblique error and root mean difference of squares were used to validate the data of this database with data measured in meteorological stations of Farkashhar, Sarablah and Silkhor in the south of the country.The results of soil moisture validation at selected stations showed that these data are able to measure the behavior and amount of soil moisture with relatively good accuracy.  The best result is obtained at Sarablah station, which shows a very good correlation coefficient (0.82), therefore ECV database data can be used to determine the behavior and amount of soil surface moisture on a large scale to compensate for the lack of terrestrial measurements inside and outside the country. The second purpose of this study is to find the effect and relationship between surface soil moisture in countries located in western Iran on the occurrence of dust in the southern and western provinces.  Regarding the relationship between the effect and the amount of surface soil moisture with the occurrence of dust, the results show that the when surface soil moisture decrease, the occurrence of dust in the interior of the same province has increased, but the decrease in soil moisture in foreign countries (western Iran), cause increasing the occurrence of dust in the entire southwestern region and even central of Iran. It was also found that the number of dust events during the cold periods of the year has increased in recent years.