Carbonate precipitation in brine – a potential trigger for tropospheric ozone depletion events R. Sander1, J. Burrows2, and L. Kaleschke2,* 1Air Chemistry Department, Max-Planck Institute of Chemistry, P.O. Box 3060, 55020 Mainz, Germany 2Institute of Environmental Physics and Remote Sensing, University of Bremen, Germany *now at: Institute of Oceanography, Center for Marine and Atmospheric Research, University of Hamburg, Germany
Abstract. Tropospheric ozone depletion events (ODEs) at high latitudes were
discovered 20 years ago and are attributed to bromine explosions.
However, an unresolved issue is the explanation of how the
acid-catalyzed reaction cycle is triggered in atmospheric particles
derived from alkaline sea water. By simulating the chemistry occuring
in polar regions over recently formed sea ice, we can model
successfully the transformation of inert sea-salt bromide to reactive
bromine monoxide (BrO) and the subsequent ODE when
precipitation of calcium carbonate from freezing sea water is taken
into account. In addition, we found the temperature dependence of the
equilibrium BrCl+Br−↔Br2Cl− to be important.
Citation: Sander, R., Burrows, J., and Kaleschke, L.: Carbonate precipitation in brine – a potential trigger for tropospheric ozone depletion events, Atmos. Chem. Phys., 6, 4653-4658, doi:10.5194/acp-6-4653-2006, 2006.