ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-12-10945-2012 Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere Tilmes S. 1 Kinnison D. E. 1 Garcia R. R. 1 Salawitch R. 2 Canty T. 2 Lee-Taylor J. 1 Madronich S. 1 Chance K. 3 National Center for Atmospheric Research, Boulder, Colorado, USA University of Maryland College Park, MD, USA Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA 20 11 2012 12 22 10945 10955 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/12/10945/2012/acp-12-10945-2012.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/12/10945/2012/acp-12-10945-2012.pdf

The impact of very short-lived (VSL) halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UV<sub>ERY</sub>) is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UV<sub>ERY</sub> due to geo-engineering for nearly all seasons and latitudes, with UV<sub>ERY</sub> rising by 12% and 6% in southern and northern high latitudes, respectively. When VSL halogen sources are neglected, future UV<sub>ERY</sub> increases due to declines in ozone column are nearly balanced by reductions of UV<sub>ERY</sub> due to scattering by the higher stratospheric aerosol burden in mid-latitudes. Consideration of VSL sources at their upper limit tips the balance, resulting in annual average increases in UV<sub>ERY</sub> of up to 5% in mid and high latitudes. Therefore, VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.

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