Multiscale simulations of tropospheric chemistry in the eastern Pacific and on the U.S. West Coast during spring 2002

	Become an AGU Member Subscribe to AGU Journals



Read Full Article (file size: 9775612 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, D23S11, doi:10.1029/2004JD004513, 2004 Multiscale simulations of tropospheric chemistry in the eastern Pacific and on the U.S. West Coast during spring 2002 Youhua Tang Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa, USA Gregory R. Carmichael Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa, USA Larry W. Horowitz Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, New Jersey, USA Itsushi Uno Research Institute for Applied Mechanics, Kyushu University, Fukuoka, Japan Jung-Hun Woo Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa, USA David G. Streets Decision and Information Sciences Division, Argonne National Laboratory, Argonne, Illinois, USA Donald Dabdub Department of Mechanical and Aerospace Engineering, University of California, Irvine, California, USA Gakuji Kurata Department of Ecological Engineering, Toyohashi University of Technology, Toyohashi, Japan Adrian Sandu Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA James Allan Department of Physics, University of Manchester Institute of Science and Technology, Manchester, UK Elliot Atlas National Center for Atmospheric Research, Boulder, Colorado, USA Franck Flocke National Center for Atmospheric Research, Boulder, Colorado, USA Lewis Gregory Huey School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA Roger O. Jakoubek Aeronomy Laboratory, NOAA, Boulder, Colorado, USA Dylan B. Millet Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA Patricia K. Quinn Pacific Marine Environmental Laboratory, NOAA, Seattle, Washington, USA James M. Roberts Aeronomy Laboratory, NOAA, Boulder, Colorado, USA Douglas R. Worsnop Aerodyne Research Inc., Billerica, Massachusetts, USA Allen Goldstein Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA Stephen Donnelly National Center for Atmospheric Research, Boulder, Colorado, USA Sue Schauffler National Center for Atmospheric Research, Boulder, Colorado, USA Verity Stroud National Center for Atmospheric Research, Boulder, Colorado, USA Kristen Johnson National Center for Atmospheric Research, Boulder, Colorado, USA Melody A. Avery NASA Langley Research Center, Hampton, Virginia, USA Hanwant B. Singh NASA Ames Research Center, Moffett Field, California, USA Eric C. Apel National Center for Atmospheric Research, Boulder, Colorado, USA Abstract Regional modeling analysis for the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) experiment over the eastern Pacific and U.S. West Coast is performed using a multiscale modeling system, including the regional tracer model Chemical Weather Forecasting System (CFORS), the Sulfur Transport and Emissions Model 2003 (STEM-2K3) regional chemical transport model, and an off-line coupling with the Model of Ozone and Related Chemical Tracers (MOZART) global chemical transport model. CO regional tracers calculated online in the CFORS model are used to identify aircraft measurement periods with Asian influences. Asian-influenced air masses measured by the National Oceanic and Atmospheric Administration (NOAA) WP-3 aircraft in this experiment are found to have lower ΔAcetone/ΔCO, ΔMethanol/ΔCO, and ΔPropane/ΔEthyne ratios than air masses influenced by U.S. emissions, reflecting differences in regional emission signals. The Asian air masses in the eastern Pacific are found to usually be well aged (>5 days), to be highly diffused, and to have low NO_y levels. Chemical budget analysis is performed for two flights, and the O₃ net chemical budgets are found to be negative (net destructive) in the places dominated by Asian influences or clear sites and positive in polluted American air masses. During the trans-Pacific transport, part of gaseous HNO₃ was converted to nitrate particle, and this conversion was attributed to NO_y decline. Without the aerosol consideration, the model tends to overestimate HNO₃ background concentration along the coast region. At the measurement site of Trinidad Head, northern California, high-concentration pollutants are usually associated with calm wind scenarios, implying that the accumulation of local pollutants leads to the high concentration. Seasonal variations are also discussed from April to May for this site. A high-resolution nesting simulation with 12-km horizontal resolution is used to study the WP-3 flight over Los Angeles and surrounding areas. This nested simulation significantly improved the predictions for emitted and secondary generated species. The difference of photochemical behavior between the coarse (60-km) and nesting simulations is discussed and compared with the observation. Received 5 January 2004; accepted 10 March 2004; published 9 July 2004. Keywords: chemical transport model; nesting simulation; atmospheric photochemistry. Index Terms: 0317 Atmospheric Composition and Structure: Chemical kinetic and photochemical properties; 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; 0368 Atmospheric Composition and Structure: Troposphere—constituent transport and chemistry; 3337 Meteorology and Atmospheric Dynamics: Numerical modeling and data assimilation. Read Full Article (file size: 9775612 bytes) Cited by Citation: Tang, Y., et al. (2004), Multiscale simulations of tropospheric chemistry in the eastern Pacific and on the U.S. West Coast during spring 2002, J. Geophys. Res., 109, D23S11, doi:10.1029/2004JD004513. Copyright 2004 by the American Geophysical Union.

Abstract