Investigation of a severe frontal dust storm over the Persian Gulf in February 2020 by CAMS model

Abstract

Severe dust storms frequently prevail over the Persian Gulf impacting the visibility and air quality. This study aims to investigate a severe dust storm that occurred during 25 to 26 February 2020 over the Persian Gulf to investigate governing synoptic patterns and CAMS model simulation in a severe frontal dust storm in the Persian Gulf area. The dust storm was severe and widespread that affected seven provinces of southern half of Iran. Also, visibility reduced under 1 km in many meteorological stations in the study area. PM10 (coarse particulate matter) amount increased more than 100 μg/m3 in most of air pollution monitoring system in south of Iran too. In this study, annual mean aerosol optical depth (AOD) was monitored for 21-year duration in this area. Then, number of dusty days is investigated in two populated islands (Kish and Qeshm) and one southern port (Dayyer port) of Iran. Synoptic patterns show the warm, cold, and occluded fronts in the study area. Also, prefrontal and postfrontal dust are obvious in satellite images on 26 February. The back trajectories from the HYSPLIT model (Hybrid Single-Particle Lagrangian Integrated Trajectory) show that dust raised from northwest of Iraq (western desert) and northeast of Saudi Arabia (Ad-Dahna desert) in this case. Noticeable visibility reduction and increased dust concentration happened at synoptic stations located in the southern sectors in Iran. Finally, CAMS (Copernicus Atmosphere Monitoring Service) model simulated PM10 in agreement with visibility in two stations: an island in the gulf and a northern port of the Persian Gulf. Also, the model output shows a good dust pattern on the study area and surface dust concentration in Iraq, Saudi Arabia, and the southwest of Iran, but it did not show well the dust mass over eastern the Persian Gulf. It can be concluded that the CAMS model simulated the dust pattern in lands better than the Persian Gulf; this could be due to the complexity of wind speed prediction at sea and land-sea interactions.