Atmospheric Investigation of Frontal Dust Storms in Southwest Asia

摘要

In this paper, an atmospheric investigation of frontal dust storms in southwest Asia is presented. Atmospheric analysis is done on six severe frontal dust storms which occurred on the Tigris and Euphrates alluvial plain dust sources in non-summer seasons during the last two decades. NCEP-NCAR Reanalysis Data were used for synoptic analysis, and the Aerosol Optical Depth (AOD) data were used to identify the dusty days, dust plumes, and estimation of the dust load over the area. Atmospheric analysis results demonstrated that in non-summer seasons, the high pressure system over the southeastern Arabian Peninsula and neighboring areas with the low pressure system over the east of the Mediterranean Sea and neighboring areas are responsible for noticeable frontal dust storms over the Tigris and Euphrates rivers valley dust sources. These circulation systems provide a favorable condition for southeastward, northeastward, and eastward transport of the dust plumes. An investigation on the affected area by the dust plumes demonstrated that southern Iraq, Kuwait and the Khuzestan province in Iran have the highest AODs and dust load during the investigated dust events. Central Iraq, western and southwestern Iran, and northeastern Saudi Arabia are the regions which were affected by frontal dust storms dust plumes more than the other areas in the Middle East. Studies have shown that the most severe frontal dust storms occurred during March and April and the analysis of the MODIS (Moderate Resolution Imaging Spectroradiometer) AODs data demonstrated that the maximum dust load over the area exceeded 5gm(-2).