HR: 0800h
AN: A31B-0849    [Abstracts]
TI: Buildup of Aerosol Loading over the Indian Ocean during the Monsoon Transition
AU: * Corrigan, C
EM: craig@fiji.ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr. m/c 0221, La Jolla, CA 92093 United States
AU: Ramanathan, V
EM: vram@fiji.ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr. m/c 0221, La Jolla, CA 92093 United States
AU: Schauer, J J
EM: jjschauer@wisc.edu
AF: Univ. of Wisconsin-Madison, Environm Chem & Technol Program, 660 N Park St., Madison, WI 53706 United States
AU: Carmichael, G
EM: gcarmich@engineering.uiowa.edu
AF: Univ. of Iowa, Ctr Global & Reg Environm Res, 4140 Seaman Center, Iowa City, IA 52240 United States
AB: In recent years, black carbon has been recognized to significantly affect radiative forcing and global climate change. The Atmospheric Brown Cloud project (ABC-Asia) has focused on measuring the anthropogenic influence of aerosols, including black carbon, to determine the extent of sunlight dimming and radiative forcing over the Asian region. The first station in the ABC network is located in the Republic of Maldives, which is located in the Indian Ocean near the southern tip of India. The presence of black carbon over the Indian Ocean varies with the cyclic nature of the Asian-Australian Monsoon. Every 6 months, the winds change directions. From May to October, the wet season brings clean air into the region from the southern hemisphere. Conversely, the dry season brings polluted air from the Indian subcontinent and South East Asia from November thru April. As a result, the region becomes charged with black carbon and other anthropogenic pollutants during the dry season. During 2004, the transition between the clean and polluted seasons resulted in nearly a 10 fold increase of scattering and absorbing aerosols. The change occurred very abruptly over a period of a few days as air from India and South East Asia arrived in the Maldives at the surface level. The new, polluted aerosol was characteristically darker since the black carbon increased more substantially than the overall aerosol scattering. As a result, the single scatter albedo was reduced from an average of 0.98 to 0.92. In addition, aerosol particles were collected using filter samplers and the aerosol composition and mass were obtained. Observed results have been compared to the CFORS regional model and show good agreement for trends and concentrations.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005