HR: 0800h
AN: A21A-0840    [Abstracts]
TI: Depth Profiles of Selected Halocarbons During PHASE-1
AU: * Yvon-Lewis, S A
EM: syvon-lewis@ocean.tamu.edu
AF: Dept. of Oceanography, Texas A&M University 3146 TAMU, College Station, TX 77843 United States
AU: King, D B
EM: daniel.king@drexel.edu
AF: Chemistry Deptartment, Drexel University, Philadelphia, PA 19104 United States
AU: Butler, J H
EM: james.h.butler@noaa.gov
AF: Climate Monitoring and Diagnostics Laboratory, NOAA R/CMDL1 325 Broadway, Boulder, CO 90303 United States
AB: The oceanic emission and uptake of atmospherically important halocarbons were studied during the Project Halogen Air-Sea Exchange study (PHASE-1). The factors controlling the production and distribution of the short-lived halocarbons in the ocean and their emission from the surface ocean are important in assessing their contribution to stratospheric ozone depletion. The shorter-lived biogenic halocarbons are reactive in the troposphere. They undergo photolysis and react with OH to produce inorganic halogens that may then react with hydrocarbons, aerosols, sulfur species, etc. Recent studies have shown that the emission of these biogenic gases at the earth's surface also can influence the chemistry of the upper troposphere and lower stratosphere [WMO, Scientific Assessment of Ozone Depletion: 2002, 2003, chap. 2]. During this study we measured the saturation state and depth profiles of selected halocarbons to assess the magnitudes of their flux into the atmosphere and their sources within the water column. Most of the depth profiles for the trace gases measured indicate that the higher concentrations are found in the upper water column above ~150m. However, a couple of compounds have slightly different profiles. Concentrations of CFC-11, which is entirely of anthropogenic origin, were highest down to a depth of ~200m in the equatorial region and down to ~350m in the gyre. Chloroform is another exception with elevated concentrations at depth and decreasing near the surface. The polybrominated methanes, CH₂Br₂ and CHBr₃, exhibit subsurface maxima at ~150m in most profiles.
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
DE: 0490 Trace gases
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005