HR: 17:30h
AN: A54B-07    [Abstracts]
TI: Semi-Empirical Models of Polar Stratospheric Ozone Depletion and Their Applications
AU: * Huck, P E
EM: p.huck@niwa.co.nz
AF: National Institute of Water and Atmospheric Research, P O Box 8602, Christchurch, 8011, New Zealand
AU: Bodeker, G E
EM: g.bodeker@niwa.co.nz
AF: National Institute of Water and Atmospheric Research, Private Bag 50061, Omakau, Central Ot, New Zealand
AU: Shepherd, T G
EM: tgs@atmosp.physics.utoronto.ca
AF: Department of Physics, University of Toronto, 60 St. George Street, Toronto, M5S, Canada
AU: Struthers, H
EM: h.struthers@niwa.co.nz
AF: National Institute of Water and Atmospheric Research, Private Bag 50061, Omakau, Central Ot, New Zealand
AU: Santee, M L
EM: mls@mls.jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, 91109, United States
AU: McDonald, A J
EM: adrian.mcdonald@canterbury.ac.nz
AF: Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
AB: Inter- and intra-annual variability in polar stratospheric ozone depletion is controlled by the interaction of gas- phase chemistry, heterogeneous chemistry, and transport. Two semi-empirical models were developed to relate the conversion of total polar stratospheric chlorine (Cl_y) to activated chlorine (ClO_x), and to then relate the rate of ozone destruction to ClO_x. The first semi-empirical model was used to calculate the daily total mass of ClO_x through a given season when provided with stratospheric temperature fields and a definition of the vortex edge. The equation is a first order differential equation relating the time rate of change of ClO_x to unactivated stratospheric chlorine (Cl_y - ClO_x) multiplied by the fraction of the vortex area containing polar stratospheric clouds and the fraction of the vortex area exposed to sunlight, and to a decay term to account for conversion back to reservoir species. The second semi-empirical model relates the time rate of change of ozone mass deficit (OMD) to the mass of activated chlorine as derived from the first equation, in-situ production of ozone and a term for dynamical entrainment of ozone rich air from lower latitudes into the polar vortex. The coefficients of both equations have been derived by optimally fitting the equations to observations and/or to output from chemistry-climate models (CCMs). The coefficients from these equations capture key sensitivities in the atmosphere that determine the interaction between climate change and polar ozone depletion. Potential applications of these coefficients include intra- seasonal projection of the severity of polar ozone depletion, evaluation of pre-1980 ozone depletion and process oriented validation of CCMs.
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting