HR: 0830h
AN: A11F-0061    [PDF]
TI: Widespread Persistent Near-Surface Ozone Depletion at Northern High Latitudes in Spring
AU: * Zeng, T
EM: tzeng@eas.gatech.edu
AF: School of Earth and Atmospheric Science, Georgia Institute of Technology, Atlanta, GA 30332 United States
AU: Wang, Y
EM: ywang@eas.gatech.edu
AF: School of Earth and Atmospheric Science, Georgia Institute of Technology, Atlanta, GA 30332 United States
AU: Chance, K
EM: kchance@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, Harvard University, Cambridge, MA 02138 United States
AU: Browell, E V
EM: Edward.V.Browell@NASA.Gov
AF: Atmospheric Sciences, NASA Langley Research Center, Hampton, VA 23681 United States
AU: Ridley, B A
EM: ridley@acd.ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80307 United States
AU: Atlas, E L
EM: atlas@acd.ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80307 United States
AU: Atlas, E L
EM: atlas@acd.ucar.edu
AF: RSMAS, University of Miami, Miami, FL 33124 United States
AB: Springtime near-surface ozone depletion has been observed at northern high latitudes. The O$_{3}$ loss is thought to be catalyzed by BrO$_{x}$ (Br + BrO). Due to limited observations, the spatial and temporal extent of low O$_{3}$ concentrations near the surface is still unknown. A regional 3-D chemistry and transport model is applied to simulate surface O$_{3}$ depletion catalyzed by bromine radicals at northern high latitudes in March and April 2000. Satellite observations of BrO column by the ESA Global Ozone Monitoring Experiment (GOME) were processed to specify the BrO concentrations in the lower troposphere. The model captures reasonably well the O$_{3}$ depletion events observed at two surface sites, Alert, Canada (82.5N, 62.3W) and Barrow, Alaska (71.3N, 156.6W), and by airborne in situ and DIAL instrument during the TOPSE experiments at northern high latitudes. Model results indicate that low O$_{3}$ concentrations ($<$20 ppbv) near the surface cover $\sim$60% of the northern high latitudes and that the depleted O$_{3}$ concentrations ($<$10ppbv) cover $\sim$20% of the region in April. The high BrO events tend to be large-scale and persistent (1-2 weeks). We find that they are correlated with low temperature, a condition conducive for heterogeneous reactions on frozen snow or aerosol surfaces.
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting