HR: 1340h
AN: A13C-1363    [Abstracts]
TI: First Results From TC⁴: Halocarbons, Hydrocarbons, Alkyl Nitrates, OCS and DMS Measured in Whole Air Samples Collected Aboard the NASA DC-8
AU: * Blake, N J
EM: nblake@uci.edu
AF: University of California, Irvine, 570 Rowland Hall, Irvine, CA 92697-2025, United States
AU: Meinardi, S
EM: smeinard@uci.edu
AF: University of California, Irvine, 570 Rowland Hall, Irvine, CA 92697-2025, United States
AU: Gorham, K
EM: kgorham@uci.edu
AF: University of California, Irvine, 570 Rowland Hall, Irvine, CA 92697-2025, United States
AU: Gartner, M
EM: gartnerm@uci.edu
AF: University of California, Irvine, 570 Rowland Hall, Irvine, CA 92697-2025, United States
AU: Yang, M
EM: myang@uci.edu
AF: University of California, Irvine, 570 Rowland Hall, Irvine, CA 92697-2025, United States
AU: Blake, D R
EM: drblake@uci.edu
AF: University of California, Irvine, 570 Rowland Hall, Irvine, CA 92697-2025, United States
AB: We present initial results from samples collected aboard the NASA DC-8 during the July and August 2007 TC⁴ campaign. All 1280 samples were analyzed by gas chromatography for selected C₂-C₁₀ nonmethane hydrocarbons, selected C₁-C₂ halocarbons (including CFCs, CH₃Br, CH₂Br₂ and CH₃I), C₁-C₅ alkyl nitrates, OCS, and DMS. During TC⁴ our measurements identified numerous air masses containing elevated levels of trace gases, of both marine and continental origin, that had been lofted to high altitude by convective systems. We compare and contrast marine emissions from the Pacific and Atlantic (Caribbean) Oceans. As reported previously, methyl nitrate levels are elevated in the equatorial Pacific marine boundary layer (MBL) but during TC⁴ levels over the Caribbean were close to background. By contrast, CH₃I proved to be a much more general tracer for MBL air in this region.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting