HR: 1340h
AN: A53C-1356    [Abstracts]
TI: Intercomparison of transpacific transport of Asian pollution between global and coupled global-regional model simulations
AU: * Park, R J
EM: rjpark@snu.ac.kr
AF: Seoul National University, San 56-1, Sillim, Gwanakgu, Seoul, 151-742, Korea, Republic of
AU: Jacob, D J
EM: djacob@fas.harvard.edu
AF: Harvard University, Pierce Hall, 29 Oxford St., Cambridge, MA 02138, United States
AU: Jang, C J
EM: Jang.Carey@epamail.epa.gov
AF: USEPA, C439-01, 109 T.W. Alexander drive, RTP, NC 27711, United States
AB: The Intercontinental transport and Climatic effects of Air Pollutants (ICAP) project supported by the U.S. EPA was launched in 2001 to enhance our understanding on transpacific Asian pollution and to improve the ability of models to quantify its influences in the United States. We participate in this work using a 3-D global chemical transport model (GEOS-Chem) which also provides dynamic chemical boundary conditions for hemispheric scale simulations by regional air quality model (CMAQ). Our focus is mainly on Asian O3 and sulfate aerosol which are two dominant Asian pollutants in the United States. We conduct a model inter-comparison of GEOS- Chem and CMAQ, and also evaluate them using observations from the Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft campaign over the western Pacific to examine important processes for Asian pollution transport. O3 and sulfate aerosol concentrations in the United States due to Asian pollution are simulated quite differently between two models despite consistent anthropogenic emissions over East Asia. CMAQ shows lower O3 but much higher sulfate aerosol concentrations in the United States relative to those of GEOS-Chem. A simple transport difference between two models cannot explain this issue. Compared with TRACE-P observations CMAQ shows lower O3 over the western Pacific due to missing processes such as stratospheric O3 influx and lightning NOx which are typically absent from regional air quality models, whereas sulfate aerosol concentration in CMAQ is higher than both observations and GEOS-Chem because of aqueous- phase chemistry and wet scavenging mainly driven by meteorological data. Our analysis indicates that proper simulations of meteorological processes such as warm-conveyor belt and deep convection are crucial for simulating transpacific transport of Asian pollution.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting