HR: 0800h
AN: A31C-0064    [Abstracts]
TI: Aerosol Ions and Their Gaseous Precursors over North America and their Sensitivity to Nitrogen Emissions
AU: * Tang, Y
EM: ytang@cgrer.uiowa.edu
AF: Center for Global and Regional Environmental Research, University of Iowa, Iowa City, IA 52242 United States
AU: Carmichael, G R
EM: gcarmich@engineering.uiowa.edu
AF: Center for Global and Regional Environmental Research, University of Iowa, Iowa City, IA 52242 United States
AU: Thongboonchoo, N
EM: nthongbo@cgrer.uiowa.edu
AF: Center for Global and Regional Environmental Research, University of Iowa, Iowa City, IA 52242 United States
AU: Horowitz, L W
EM: larry.horowitz@noaa.gov
AF: NOAA Geophysical Fluid Dynamics Laboratory, Princeton University, Princeton, NJ 08542 United States
AU: Dabdub, D
EM: ddabdub@uci.edu
AF: Department of Mechanical and Aerospace Engineering, University of California at Irvine, Irvine, CA 92697 United States
AU: Sandu, A
EM: asandu@cs.vt.edu
AF: Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 United States
AU: Weber, R J
EM: rweber@eas.gatech.edu
AF: School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332 United States
AU: Heckel, A
EM: Andreas.Heckel@iup.physik.uni-bremen.de
AF: Institute of Environmental Physics, University of Bremen Kufsteinerstr. 1, Bremen, 28359 Germany
AB: During the ITCT-2K2 and ICARTT-2k4 experiments, a regional chemical transport model, STEM-2K3, was applied to study developed to study the aerosol ions, their precursors, and photochemistry. The major anions: sulfate and nitrate, show obvious geographic distribution from west to east coasts: nitrate is the dominant anion in west coast, and sulfate is the major anion in east coast. It reflects the distribution of NOx and SO2 sources and the influence of prevailing wind directions. The model also reveals that sulfate is the major component of aerosol extinction coefficients in Eastern and Southeastern USA during the ICARTT experiment. Ammonia emissions play an important role on controlling the ratio of nitrate versus HNO3 over inland states. Sea salt is the one of major influence factors in the coast regions. Our three-dimensional model revealed the procedure of aerosol secondary uptake when airmasses move from west to east. Using modeled regional tracers to identify the airmass sources, the aerosols also show source-related distributions. The SO2 industrial emissions, such as power plants, are the major sources of sulfate. The sulfate formation illustrates the non-local effect associated with transport and diffusion. Simulated carbonaceous concentrations are also discussed with equilibrium assumption. The consideration of aerosol secondary partition is important not only for aerosol prediction, but also for gaseous chemistry. The sensitivity studies with and without nitrate aerosol formation revealed its influence on gaseous HNO3, NOy concentrations and photochemical products.
DE: 3337 Numerical modeling and data assimilation
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting