HR: 09:00h
AN: A41D-05    [Abstracts]
TI: Summertime influence of Asian pollution in the middle and upper troposphere during INTEX-A
AU: * Liang, Q
EM: qing@atmos.washington.edu
AF: University of Washington, Box 351640, Seattle, WA 98195
AU: Jaegle, L
EM: jaegle@atmos.washington.edu
AF: University of Washington, Box 351640, Seattle, WA 98195
AU: Hudman, R
EM: hudman@fas.harvard.edu
AF: Harvard University, Pierce Hall, Cambridge, MA 02138
AU: Turquety, S
EM: turquety@fas.harvard.edu
AF: Harvard University, Pierce Hall, Cambridge, MA 02138
AU: Jacob, D
EM: djacob@fas.harvard.edu
AF: Harvard University, Pierce Hall, Cambridge, MA 02138
AU: Avery, M
EM: m.a.avery@larc.nasa.gov
AF: NASA, Langley Research Center, Hampton, VA 23681
AU: Sachse, G
EM: g.w.sachse@larc.nasa.gov
AF: NASA, Langley Research Center, Hampton, VA 23681
AU: Blake, D
EM: drblake@uci.edu
AF: UC Irvine, 570 Rowland Hall, Irvine, CA 92697
AU: Browell, E
EM: e.v.browell@larc.nasa.gov
AF: NASA, Langley Research Center, Hampton, VA 23681
AU: Brune, W
EM: brune@ems.psu.edu
AF: Penn. State U., 503 Walker Building, University Park, PA 16802
AU: Ren, X
EM: ren@essc.psu.edu
AF: Penn. State U., 503 Walker Building, University Park, PA 16802
AU: Cohen, R
EM: cohen@cchem.berkeley.edu
AF: Chemistry Dept., UC Berkeley, Berkeley, CA 94720
AU: Dibb, J
EM: jack.dibb@unh.edu
AF: U. of New Hampshire, Climate Research Center, Durham, NH 03824
AU: Fuelberg, H
EM: fuelberg@met.fsu.edu
AF: Meteorology Dept., Florida State Univ., Tallahassee, FL 32306
AU: Porter, M
EM: mporter@met.fsu.edu
AF: Meteorology Dept., Florida State Univ., Tallahassee, FL 32306
AU: Huey, G
EM: greg.huey@eas.gatech.edu
AF: Earth & Atmospheric Sci., Georgia Tech., Atlanta, GA 30332
AU: Singh, H
EM: hanwant.b.singh@nasa.gov
AF: NASA, Ames Research Center, Moffett Field, CA 94035
AU: Wennberg, P
EM: wennberg@gps.caltech.edu
AF: California Institute of Tech., MC150-21, Pasadena, CA 91125
AB: We analyze aircraft observations obtained during INTEX-A (1 July - 14 August 2004) with the GEOS-CHEM global model of tropospheric chemistry to understand the influence of Asian pollution in the middle and upper troposphere over the United States (US) during summer. We apply Principal Component Analysis (PCA) to the observations and find 4 major types of airmasses: Asian, lower stratospheric, convection/lightning, and background. PCA identifies five major Asian pollution plumes during INTEX-A, consistent with results from the GEOS-CHEM model and back-trajectories. The geographic distributions of the Asian plumes span from the remote northeastern Pacific to the US east coast, where they join the local pollution outflow to the North Atlantic. The major trans-Pacific transport mechanisms were export in warm conveyor belts of mid-latitude cyclones as well as deep convection followed by advection in the middle and upper troposphere, with differing transport times (3-10 days), transport altitudes (5-11 km), and chemical compositions. On average, observed mixing ratios were significantly enhanced in Asian plumes compared to background airmasses in the middle and upper troposphere: CO (ΔCO = 19 ppbv relative to 94 ppbv for background aimasses), O₃ (ΔO₃ = 26 ppbv, background = 74 ppbv), PAN (ΔPAN = 270 pptv, background = 335 ppbv), HNO₃ (ΔHNO₃ = 125 pptv, background = 237 pptv), C₂H₆ (ΔC₂H₆ = 180 pptv, background = 744 pptv), C₂H₂ (ΔC₂H₂ = 93 pptv, background = 84 pptv), HCN (ΔHCN = 146 pptv, background = 271 pptv), and CH₃OH (ΔCH₃OH = 1006 pptv, background = 1364 pptv). Individual Asian plumes have very different ΔO₃/ΔCO ratios, ranging from -0.27 to 1.11. Some of the very large O₃ enhancements appear to be due to mixing of Asian airmasses with lower stratospheric air. Through detailed case studies, we will examine the influence of transport pathways, chemical evolution, wet deposition, and stratosphere-troposphere exchange on the composition of these Asian pollution plumes.
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005