Atmos. Chem. Phys. Discuss., 9, 8903-8941, 2009
www.atmos-chem-phys-discuss.net/9/8903/2009/
doi:10.5194/acpd-9-8903-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
BrO, blizzards, and drivers of polar tropospheric ozone depletion events
A. E. Jones1, P. S. Anderson1, M. Begoin2, N. Brough1, M. A. Hutterli1, G. J. Marshall1, A. Richter2, H. K. Roscoe1, and E. W. Wolff1
1British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
2Institute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany

Abstract. The source of bromine that drives polar boundary layer ozone depletion events (ODEs) is still open to some debate. While ODEs are generally noted to form under conditions of a shallow stable boundary layer, observations of depleted air under high wind conditions are taken as being transport-related. Here we report observations from Antarctica in which an unusually large cloud of BrO formed over the Weddell Sea. The enhanced BrO was observed over Halley station in coastal Antarctica, providing an opportunity to probe the conditions within an active "bromine explosion" event. On this occasion, enhanced BrO and depleted boundary layer ozone coincided with high wind speeds and saline blowing snow. We derive a simple model to consider the environmental conditions that favour ODEs and find two maxima, one at low wind/stable boundary layer and one at high wind speeds with blowing snow. Modelling calculations aiming to reproduce the wider regional or global impacts of ODEs, either via radiative effects or as a halogen source, will also need to account for high wind speed mechanisms.

Citation: Jones, A. E., Anderson, P. S., Begoin, M., Brough, N., Hutterli, M. A., Marshall, G. J., Richter, A., Roscoe, H. K., and Wolff, E. W.: BrO, blizzards, and drivers of polar tropospheric ozone depletion events, Atmos. Chem. Phys. Discuss., 9, 8903-8941, doi:10.5194/acpd-9-8903-2009, 2009.
 
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