Abstract:
The present work examines the characteristics (source regions, pathways, vertical profiles) as well as the meteorological conditions and the role of the Inter-Tropical Convergence Zone (ITCZ) during a dust event on 1–3 July 2014 over southwest (SW) Asia. NCEP/NCAR reanalysis, meteorological and satellite remote sensing (MODIS, Meteosat, CALIPSO) observations are utilized. The major dust storm (AOD550 up to 1.5– 2.0) was generated in the southern Karakum desert in Turkmenistan as a result of intense north winds (Levar), due to enhanced pressure gradient between the Caspian Sea and Hindu Kush Mountains. The dust
storm was vertically extended up to 5 km over the arid terrain of SW Asia, as a consequence of the deep mixing layer and increased convection, while over northern Arabian Sea it was mixed with another dust plume coming from Arabia and marine aerosols due to strong monsoon winds within the boundary layer. The regional topography, variations in pressure, monsoon circulation and the position of the ITCZ play a decisive role on modulation of the wind field, dust-storm pathways and vertical distribution of dust. Enhanced knowledge of atmospheric circulation and processes responsible for dust export over SW Asia and Arabian Sea in linkage to the Levar wind and Indian summer monsoon is essential for improving dust forecasts and simulations over the region.
