HR: 1340h
AN: A33A-0860    [Abstracts]
TI: Fine Mode Aerosol over the United Arab Emirates
AU: * Ross, K E
EM: kristy@crg.bpb.wits.ac.za
AF: Climatology Research Group, Univeristy of the Witwatersrand, Private Bag 3, Wits, 2050 South Africa
AU: Piketh, S J
EM: stuart@crg.bpb.wits.ac.za
AF: Climatology Research Group, Univeristy of the Witwatersrand, Private Bag 3, Wits, 2050 South Africa
AU: Reid, J S
EM: reidj@nrlmry.navy.mil
AF: Naval Research Laboratory, 7 Grace Hopper Avenue, Monterey, CA 93943-5502 United States
AU: Reid, E A
EM: reidb@nrlmry.navy.mil
AF: Naval Research Laboratory, 7 Grace Hopper Avenue, Monterey, CA 93943-5502 United States
AB: The aerosol loading of the atmosphere over the Arabian Gulf region is extremely diverse and is composed not only of dust, but also of pollution that is derived largely from oil-related activities. Fine mode pollution particles are most efficient at scattering incoming solar radiation and have the potential to act as cloud condensation nuclei (CCN), and may therefore have implications for climate change. The smaller aerosols may also pose a health hazard if present in high concentrations. The United Arab Emirates Unified Aerosol Experiment (UAE²) was designed to investigate aerosol and meteorological characteristics over the region using ground-based, aircraft and satellite measurements, and was conducted in August and September 2004. Aerosol chemical composition has been obtained from filters that were collected at the site of the Mobile Atmospheric Aerosol and Radiation Characterization Observatory (MAARCO) on the coast of the UAE between Abu Dhabi and Dubai. Filter samples were also collected on an airborne platform in order to assess how aerosol chemical composition varies across the region and throughout the depth of the boundary layer. Results of the analysis of the PM2.5 coastal samples show that ammonium sulphate is the most prevalent constituent of the fine mode aerosol in the region (>50% of the mass), followed by organic matter, alumino-silicates, calcium carbonate and black carbon. Source apportionment indicates that most of the fine aerosol mass is derived from fossil fuel combustion, while mineral dust and local vehicle emissions also contribute to the fine aerosol loading. The organic carbon-to-total carbon ratio of the aerosol is 0.65, which is typical of fossil fuel combustion. The dominance of sulphates means that the fine mode aerosol in the region is probably responsible for a negative radiative forcing, and that the polluting emissions significantly elevate the concentration of CCN.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005