Abstract
JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 109,
D19S23,
32 PP., 2004
doi:10.1029/2003JD004201
Three-dimensional simulations of inorganic aerosol distributions in east Asia during spring 2001
Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa, USA
Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa, USA
Departments of Chemical Engineering and Environmental Science and Engineering, California Institute of Technology, Pasadena, California, USA
Department of Mechanical and Aerospace Engineering, University of California, Irvine, California, USA
School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii, USA
School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii, USA
Department of Chemistry and Biochemistry, University of California, San Diego, California, USA
Department of Chemistry and Biochemistry, University of California, San Diego, California, USA
Department of Chemistry and Biochemistry, University of California, San Diego, California, USA
Research Institute for Applied Mechanics, Kyushu University, Fukuoka, Japan
Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa, USA
Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa, USA
Decision and Information Sciences Division, Argonne National Laboratory, Argonne, Illinois, USA
Pacific Marine Environmental Laboratory, NOAA, Seattle, Washington, USA
Pacific Marine Environmental Laboratory, NOAA, Seattle, Washington, USA
Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea
Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa, USA
Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
Department of Earth Sciences, University of New Hampshire, Durham, New Hampshire, USA
Department of Earth Sciences, University of New Hampshire, Durham, New Hampshire, USA
In this paper, aerosol composition and size distributions in east Asia are simulated using a comprehensive chemical transport model. Three-dimensional aerosol simulations for the TRACE-P and ACE-Asia periods are performed and used to help interpret actual observations. The regional chemical transport model, STEM-2K3, which includes the on-line gas-aerosol thermodynamic module SCAPE II, and explicitly considers chemical aging of dust, is used in the analysis. The model is found to represent many of the important observed features. The Asian outflow during March and April of 2001 is heavily polluted with high aerosol loadings. Under conditions of low dust loading, SO2 condensation and gas phase ammonia distribution determine the nitrate size and gas-aerosol distributions along air mass trajectories, a situation that is analyzed in detail for two TRACE-P flights. Dust is predicted to alter the partitioning of the semivolatile components between the gas and aerosol phases as well as the size distributions of the secondary aerosol constituents. Calcium in the dust affects the gas-aerosol equilibrium by shifting the equilibrium balance to an anion-limited status, which benefits the uptake of sulfate and nitrate, but reduces the amount of aerosol ammonium. Surface reactions on dust provide an additional mechanism to produce aerosol nitrate and sulfate. The size distribution of dust is shown to be a critical factor in determining the size distribution of secondary aerosols. As much of the dust mass is found in the supermicron mode (70–90%), appreciable amounts of sulfate and nitrate are found in the supermicron particles. For sulfate the observations and the analysis indicate that 10–30% of sulfate is in the supermicron fraction during dust events; in the case of nitrate, more than 80% is found in the supermicron fraction.
Received 1 October 2003; accepted 24 February 2004; published 25 August 2004.
Citation: (2004), Three-dimensional simulations of inorganic aerosol distributions in east Asia during spring 2001, J. Geophys. Res., 109, D19S23, doi:10.1029/2003JD004201.
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