HR: 0800h
AN: A11C-0608    [Abstracts]
TI: Using CFC-12 and HCl to quantify the annual cycle of the stratospheric contribution to ozone in the Arctic troposphere
AU: * Liang, Q
EM: liang@code916.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 613.3, Greenbelt, MD 20771, United States
AU: * Liang, Q
EM: liang@code916.gsfc.nasa.gov
AF: Oak Ridge Associated Universities, NASA Postdoctoral Program, Oak Ridge, TN 37831, United States
AU: Douglass, A R
EM: Anne.R.Douglass@nasa.gov
AF: NASA Goddard Space Flight Center, Code 613.3, Greenbelt, MD 20771, United States
AU: Duncan, B N
EM: Bryan.N.Duncan@nasa.gov
AF: NASA Goddard Space Flight Center, Code 613.3, Greenbelt, MD 20771, United States
AU: Duncan, B N
EM: Bryan.N.Duncan@nasa.gov
AF: Goddard Earth Sciences & Technology Center, University of Maryland, Baltimore County, Baltimore, MD 21228, United States
AU: Stolarski, R S
EM: Richard.S.Stolarski@nasa.gov
AF: NASA Goddard Space Flight Center, Code 613.3, Greenbelt, MD 20771, United States
AU: Witte, J C
EM: witte@gavial.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 613.3, Greenbelt, MD 20771, United States
AU: Witte, J C
EM: witte@gavial.gsfc.nasa.gov
AF: Science Systems and Applications, Inc., (SSAI), Lanham, MD 20706, United States
AB: In this study, we use CFC-12 and hydrochloric acid (HCl) to quantify the annual cycle of stratosphere-to- troposphere transport of O3 to the Arctic troposphere. To do so, we analyze results from a 5-year stratosphere and troposphere simulation from the Global Modeling Initiative (GMI) Chemical Transport Model (CTM) for 1994- 1998 and a 10-year simulation using the GEOS Chemistry Climate Model (GEOS CCM) for 1995-2004. The later includes a tagged CFC-12 tracer to track the transport of aged stratospheric air into the troposphere. We compare the simulated CFC-12 with 10 years surface CFC-12 measurements at two NOAA-GMD sites, Alert and Barrow. We compare O3 with 10 years of ozonesondes at Alert, Eureka, and Resolute. CFC-12, HCl and O3 are all compared with satellite observations from the Advanced Composition Explorer (ACE) and several MkIV balloon measurements in the Arctic. The GEOS CCM and GMI CTM simulations capture well the observed magnitude and annual cycle of CFC-12, HCl, and O3 in the stratosphere and troposphere. Since CFC-12 is emitted at the surface and destroyed in the stratosphere while HCl and O3 are produced in the stratosphere, the stratospheric air shows strong correlation between HCl and O3 and anti-correlation between CFC-12 and O3. We use the CFC-12 tagged tracer to track the transport from the stratosphere to the troposphere and the subsequent transport into the lower troposphere in the Arctic. HCl is paired with O3 to quantify the stratospheric contribution to O3 in the troposphere by applying a scaling factor to the simulated HCl using the HCl-O3 regression ratio. O3 and its annual cycle in the upper troposphere are dominated by stratospheric influence, which peaks in spring. The stratospheric contribution decreases as altitude decreases, accompanied by a delay in the phase of maximum. In the middle troposphere (2-6km), the stratospheric contribution peaks during the summer and is comparable to that of net photochemistry. Due to inefficient transport into the lower Arctic surface, the stratospheric contribution of O3 at the surface accounts for only a few (<5) ppbv.
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
DE: 3362 Stratosphere/troposphere interactions
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting