Linking ground-satellite observations with HYSPLIT Back trajectory modeling to identify dust sources affecting Western Iran: A case study in Lorestan province

Background: This study combined ground and satellite observations with the results of HYSPLIT model to identify the origin, transport, and deposition of sand and dust storms (SDSs) affecting Western Iran. Methods: Field-measured dust exposure data were obtained during 2000-2014 to analyze variability of dust concentration and dust intensity at annual, monthly, and daily scales. Remote sensing measurements in this research include the analysis of a total of eight (Level 1B Calibrated Radiances 1 km (MOD021KM)) MODIS tiles selected based on interpreting the results of ground observations to capture the major SDS events occurred between 2000 and 2014. Results: The results, indicating a sharp rise in the number of dusty days from 2008 onwards, were used as a basis to identify the spatial coverage and intensity of SDSs over the central part of the Middle East and the study province using a number of eight MODIS images. According to the back trajectory analysis of Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT), the MODIS-derived SDSs were found to have both national and international sources. The most prevalent and powerful source was likely to initiate from deserts of Syria and Iraq by air masses coming from the Mediterranean Sea and terminate in Western Iran where the Zagros Mountains Chain blocks easterly winds. Conclusion: Despite the evident link between timing of regional SDSs and in situ observations, the contribution of local dust sources in the west of the province should be also investigated to provide insights into the development and spread of SDS events affecting Western Iran, especially Lorestan Province.