HR: 13:40h
AN: A13F-01 INVITED    [Abstracts]
TI: Climate-Relevant Properties of Atmospheric Aerosols Over Megacity Regions in China
AU: * Andreae, M O
EM: andreae@mpch-mainz.mpg.de
AF: Biogeochemistry Department, Max Planck Institute for Chemistry, P O Box 3060, Mainz, D- 55020, Germany
AU: Garland, R
EM: garland@mpch-mainz.mpg.de
AF: Biogeochemistry Department, Max Planck Institute for Chemistry, P O Box 3060, Mainz, D- 55020, Germany
AU: Gunthe, S
EM: gunthe@mpch-mainz.mpg.de
AF: Biogeochemistry Department, Max Planck Institute for Chemistry, P O Box 3060, Mainz, D- 55020, Germany
AU: Poeschl, U
EM: poeschl@mpch-mainz.mpg.de
AF: Biogeochemistry Department, Max Planck Institute for Chemistry, P O Box 3060, Mainz, D- 55020, Germany
AU: Rose, D
EM: rose@mpch-mainz.mpg.de
AF: Biogeochemistry Department, Max Planck Institute for Chemistry, P O Box 3060, Mainz, D- 55020, Germany
AU: Schmid, O
EM: otmar.schmid@gsf.de
AF: Biogeochemistry Department, Max Planck Institute for Chemistry, P O Box 3060, Mainz, D- 55020, Germany
AU: Yang, H
EM: hyang@mpch-mainz.mpg.de
AF: Biogeochemistry Department, Max Planck Institute for Chemistry, P O Box 3060, Mainz, D- 55020, Germany
AU: Zhang, Y
EM: yhzhang@pku.edu.cn
AF: College of Environmental Sciences, Peking University, Beijing, 100871, China
AU: Zhu, T
EM: tzhu@pku.edu.cn
AF: College of Environmental Sciences, Peking University, Beijing, 100871, China
AB: We conducted measurements of optical and cloud-nucleating properties of the atmospheric aerosol over urban and peri-urban regions in northern and southern China (Beijing and Guangzhou areas). We measured light scattering with a nephelometer at several wavelengths and light absorption with a photoacoustic spectrometer at 532 nm. Because the latter instrument measures the absorption on airborne particles, it is free from filter artefacts and provides high accuracy. The cloud-nucleating properties of size-selected aerosol were determined with a DMT CCN counter. Urban aerosols were found to be highly absorbing, as a result of strong emissions of soot particles mostly from vehicular sources. Regional aerosols were somewhat less absorbing due to the continued production of secondary inorganic (sulfate, nitrate) and organic aerosol. Aerosol from biomass burning also made substantial contributions to the atmospheric burden. Absolute values of the scattering and absorption coefficients were very high, especially during the northeastern monsoon in Guangzhou. A negative correlation between single scattering albedo and backscatter fraction was observed and found to have a strong non-linear effect on aerosol radiative forcing efficiency. High CCN concentrations were present over both regions. In spite of the relatively young age of the aerosols, most of the particles contained enough soluble material to be able to activate at intermediate supersaturations. The hygroscopicity of the particles was in general similar or higher than that observed in regional aerosol from Europe or other polluted regions.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0321 Cloud/radiation interaction
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting