HR: 12:05h
AN: A42B-08    [Abstracts]
TI: Simulating Arctic bromine explosion and surface ozone depletion with the GEM-AQ model
AU: Toyota, K
EM: ktoyota@yorku.ca
AF: York University, Department of Earth and Space Science and Engineering, 4700 Keele St, Toronto, ON M3J 1P3, Canada
AU: * McConnell, J C
EM: jcmcc@yorku.ca
AF: York University, Department of Earth and Space Science and Engineering, 4700 Keele St, Toronto, ON M3J 1P3, Canada
AU: Neary, L
AF: York University, Department of Earth and Space Science and Engineering, 4700 Keele St, Toronto, ON M3J 1P3, Canada
AU: Lupu, A
AF: York University, Department of Earth and Space Science and Engineering, 4700 Keele St, Toronto, ON M3J 1P3, Canada
AU: Kaminski, J W
AF: York University, Department of Earth and Space Science and Engineering, 4700 Keele St, Toronto, ON M3J 1P3, Canada
AU: Jarosz, J
AF: York University, Department of Earth and Space Science and Engineering, 4700 Keele St, Toronto, ON M3J 1P3, Canada
AU: Gong, S
AF: Science and Technology Branch, Environment Canada, 4905 Dufferin St, Toronto, ON M3H 5T4, Canada
AU: Kwok, R
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109, United States
AU: Anlauf, K
AF: Science and Technology Branch, Environment Canada, 4905 Dufferin St, Toronto, ON M3H 5T4, Canada
AU: Kikuchi, T
AF: Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan
AU: Richter, A
AF: Institute of Environmental Physics, University of Bremen, P.O. Box 33 04 40, Bremen, D- 28334, Germany
AU: McLinden, C A
AF: Science and Technology Branch, Environment Canada, 4905 Dufferin St, Toronto, ON M3H 5T4, Canada
AB: Episodes of bromine explosion and surface ozone depletion during the Arctic Springtime (for the years of 2000 and 2001) are simulated with an online air-quality transport model, GEM-AQ, and compared with in-situ measurements of ozone, temperature and wind speed/direction at the ground level and their profiles at selected stations as well as satellite BrO column measurements. GEM-AQ is implemented with tropospheric oxidant chemistry, gas-phase and heterogeneous bromine chemistry, and multi-component aerosol chemistry and microphysics. At this point model runs are performed with global variable-resolution horizontal grids having a high-resolution Arctic core at approximately 100 km resolution. A series of 30 hours meteorological forecasts are carried out, of which the first 6 hours are spin-up from objective analysis at different resolution and the last 24 hours are used for chemical transport simulation over months. Dry deposition velocities for HOBr, BrNO3 and HBr on the snow/ice pack are calculated online and their deposition is assumed to be converted to Br2 emission back to the atmosphere. Fresh, first-year sea ice is assumed to release Br2 as fresh emission and be more efficient at releasing Br2 than old, multi-year sea ice. We use the QuickSCAT satellite data of multi-year seaice fraction and Canadian Meteorological Centre's surface analysis of total seaice fraction for estimating the first-year fraction. Fair agreement is obtained between observed and simulated variabilities in surface ozone mixing ratios at Alert, Barrow and Zeppelinfjell on the timescale of several days, indicating the source region of bromine and synoptic- scale mass transport are simulated well. However, occasional, abrupt recovery of surface ozone at Alert is not captured by the model. Comparison with observed temperature and winds demonstrates that the model at the current resolution does not resolve abrupt wind episodes mediated by local mountain topography (e.g. Alert, Eureka, Zeppelinfjell); otherwise, simulated wind speed/direction agree well with the data from stations within relatively smooth topography (e.g. Barrow, Resolute, Inuvik) and from an ice floe buoy near the north pole.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting