Houssos E.E, Chronis T., Fotiadi A. and Hossain F. (2014)
Monthly Weather Review (published online). DOI: 10.1175/MWR-D-14-00198.1
Abstract
This study examines the atmospheric circulation characteristics of Dust Outbreaks (DO) over the Arabian Peninsula. Based on a 12-year (1999-2011) AERONET (Aerosol Robotic Network) database over the Solar Village and criteria pertinent to the Aerosol Optical Depth at 500 nm and Ångström exponent, 177 DO have been identified. Factor and Cluster analysis on 1000 and 700 hPa geopotential heights are further employed to identify the main types of the atmospheric circulation leading to the respective DO. During the winter season, the anticyclonic circulation intensifies over the Middle East causing the strengthening of the pressure gradient over the Arabian Peninsula, inducing northerly winds over the study region, hence favoring dust entrainment in the atmosphere. More often, the passage of mid-latitude cyclones over northern or central Arabian Peninsula is accompanied by postfrontal northerly winds also promoting the presence of DO in the region. The DO during spring over the region are likely favored by the enhancement of convective activity, as the thermal low over the Arabian Peninsula builds and the dynamics of the upper troposphere. During summer the pressure gradient over the study region is greatly enhanced due to the extension of the subtropical Azores anticyclone over the Mediterranean. The latter is the main driver triggering the DO events.