HR: 1340h
AN: A43A-0871    [Abstracts]
TI: Impact of Recent Laboratory Measurements of the ClOOCl Absorption Cross Section On Our Understanding of Polar Ozone Chemistry
AU: * Canty, T
EM: tcanty@atmos.umd.edu
AF: University of Maryland, CSS Bldg, Room 2411, College Park, MD 20742, United States
AU: Rex, M
EM: mrex@awi-potsdam.de
AF: Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, Potsdam, D-14473, Germany
AU: Salawitch, R
EM: rjs@atmos.umd.edu
AF: University of Maryland, CSS Bldg, Room 2411, College Park, MD 20742, United States
AU: Schofield, R
EM: robyn.schofield@gmail.com
AF: Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, Potsdam, D-14473, Germany
AU: Stimpfle, R
EM: rick@huarp.harvard.edu
AF: Harvard University, Dept of Chemistry and Chemical Biology, Cambridge, MA 02138, United States
AU: Stroh, F
EM: f.stroh@fz-juelich.de
AF: Forschungszentrum Jülich, ICG-I: Stratosphäre, Julich, D-52425, Germany
AU: von Hobe, M
EM: m.von.hobe@fz-juelich.de
AF: Forschungszentrum Jülich, ICG-I: Stratosphäre, Julich, D-52425, Germany
AU: Wilmouth, D
EM: wilmouth@fas.harvard.edu
AF: Harvard University, Dept of Chemistry and Chemical Biology, Cambridge, MA 02138, United States
AB: The photolysis of ClOOCl is crucial in determining the rate of polar ozone loss due to the ClO+ClO cycle. New laboratory measurements of the ClOOCl cross section suggest that its photolysis is about a factor of six slower than a value based on current recommendations. We show the incorporation of these new cross sections into a photochemical model leads to poor agreement with values of ClO and ClOOCl measured during the SOLVE and VINTERSOL campaigns. For both campaigns the model under-estimates measured ClO and over-estimates measured ClOOCl by amounts that are much larger than the measurement uncertainties. We also examine implications of the new ClOOCl cross section measurement on the chlorine budget, using observations of ClO and HCl from Aura MLS and ClNO3 from ACE. These comparisons indicate that a model using the new cross section, and no other changes, provides a poor description of the chlorine photochemistry. Such a simulation also results in much slower ozone loss rates compared to a model using standard chemistry. We use the various data sets to test a variety of processes that could be invoked to resolve these discrepancies. Implications of proposed new chemical mechanisms for ozone loss rates are also discussed.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0317 Chemical kinetic and photochemical properties
DE: 0340 Middle atmosphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting