Investigation of aerosol optical, physical, and radiative characteristics of a severe dust storm observed over UAE

This work presents a detailed study of the dynamical processes triggering the occurrence of the two heavy dust storms which occurred between 18 and 22 March 2012 over the Middle East. The dynamics of this event are related to the coupling of subtropical jet and polar jet over the Saudi Arabia region, resulting in massive dust storm generation and dust transport through Rub’ al Khali and the Persian Gulf to the UAE region. AOD and PM10 values showed a fourfold increase during the event reaching a maximum of 1.8 and 1653μg/m3 respectively. The spatial extent of the dust storm is evident from high values of MODIS AOD (~1.5) and OMI aerosol index (4.5) covering the entire Middle East. The total attenuated backscatter at 550nm from CALLIPSO showed the vertical extent of dust up to 8km. In addition, surface temperature showed a decrease of almost 15°C during the event signifying the intensity of the dust storm. Aerosol radiative forcing estimates during the dust storm showed a cooling at the surface and warming in the atmosphere, with a maximum forcing value reaching up to ~−210Wm−2 (185 Wm−2). Hence, it is evident from the present study that the dust layer caused an additional warming of ~150Wm−2 in the atmosphere over this region. The present event showcases the importance of dust storm induced aerosol optical and physical processes, and associated atmospheric dynamics over UAE as well as other affected regions.