Introduction

Nowadays, the occurrence of dust storms represents one of the most significant natural hazards in many countries around the world, particularly those located within the global dust belt. The Middle East, as a region situated in this dust belt, contains numerous active dust sources. Fine dust particles emitted from these sources are subsequently transported to downwind areas, often over long distances. The Persian Gulf and the Sea of Oman, two large water bodies in the Middle East, are affected annually by surrounding dust sources. These marine regions are not only ecologically sensitive but also of great economic importance for fisheries, shipping, and oil transportation. The synoptic patterns governing the region, along with prevailing wind directions, cause dust storms to pass directly over these sensitive marine environments. Pollution resulting from the transport of fine dust particles from surrounding hotspots to the Persian Gulf and the Sea of Oman is a major environmental challenge. It has created negative impacts that could damage the biodiversity of these water bodies, even in the short term. According to recent studies, the Persian Gulf and the Sea of Oman regions are among the most polluted marine areas in the world. In this study, three widespread dust phenomena over the Persian Gulf and the Sea of Oman were investigated, representing the summer, spring, and winter seasons.

Methodology

Satellite data and surface observations from Iranian synoptic stations were used to detect dust masses and assess the severity of the studied storms. To examine the mechanisms responsible for these dust events in different seasons, a synoptic analysis was performed using NCEP/NCAR reanalysis data. The HYSPLIT trajectory model was employed to identify different dust sources in the region that affect the Persian Gulf and the Sea of Oman during the selected case studies. Finally, the WRF-Chem numerical model was run to evaluate its capability in forecasting dust storms over the Persian Gulf and the Sea of Oman.

Results and Discussion

Satellite true-color images revealed heavy dust masses covering a large part of the Persian Gulf, the Strait of Hormuz, and the Sea of Oman during all three cases. Aerosol optical depth (AOD) values were significant over most of the study area. Horizontal visibility data from meteorological stations also confirmed a marked decrease in visibility, especially at stations in Hormozgan province during these dust events. Visibility reductions in some cases dropped below 500 meters, indicating severe dust storm conditions. The synoptic analysis indicated different systems in the three case studies. In the summer dust storm, a thermal low-pressure system and northwesterly winds (Shamal wind) over northern Iraq were observed. At mid-tropospheric levels, subtropical high-altitude ridges extended from northeastern Africa to the Red Sea, Saudi Arabia, and western parts of Iran. During the spring case study, the presence of a dynamic low-pressure system and its associated cold front caused severe winds and dust emission from the surface. Thus, this spring dust storm was classified as a frontal dust event. Additionally, a deep trough was present over the region during this case. In the winter season case, severe winds around a dynamic low-pressure system led to the formation of a dust storm. Specifically, in the first case (summer), a negative pressure anomaly over southern areas was observed; in the second case (spring), a negative altitude anomaly in the trough position over northern Iraq; and in the third case (winter), a significant pressure decrease over the study area was noted. These distinct synoptic configurations highlight the seasonal variability in dust storm triggers over the region. The outputs of the HYSPLIT model showed that the main dust pathes passed through southern Iraq, northern and eastern Saudi Arabia, Kuwait, the United Arab Emirates (UAE), as well as sources located in southern Iran during all case studies. Back-trajectory analysis confirmed that air parcels arriving over the Persian Gulf and the Sea of Oman originated primarily from these arid and semi-arid regions. The outputs of the WRF-Chem model correctly predicted the spatial and temporal distribution of high dust concentrations and the prevailing wind pattern in the region, highlighting the simultaneous role of different regional sources in the occurrence of these dust events.

Conclusion

The results showed that there are different mechanisms causing dust storms over the Persian Gulf and the Sea of Oman, as well as various dust sources surrounding these water bodies. Dust sources in Syria, Iraq, Saudi Arabia, Kuwait, the UAE, Oman, and Iran contributed to these severe storms in the study area. Studying the synoptic systems responsible for the emission and transport of dust particles to the Persian Gulf and the Sea of Oman in different seasons can lead to more accurate dust storm forecasts in the future. Furthermore, based on the findings, numerical models such as WRF-Chem can be used as reliable tools to forecast severe dust storms over the Persian Gulf and the Sea of Oman.