Atmos. Chem. Phys. Discuss., 9, 25361-25407, 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.
Iodine monoxide in the Antarctic snowpack
U. Frieß1, T. Deutschmann1, B. Gilfedder2, R. Weller3, and U. Platt1
1Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany
2Institut für Umweltgeologie, TU-Braunschweig, Germany
3Alfred Wegener Institut für Polar- und Meeresforschung, Bremerhaven, Germany

Abstract. Recent ground-based and space borne observations suggest the presence of significant amounts of iodine monoxide in the boundary layer of Antarctica, which are expected to have an impact on the ozone budget and might contribute to the formation of new airborne particles. So far, the source of these iodine radicals has been unknown. This paper presents long-term measurements of iodine monoxide at the German Antarctic research station Neumayer, which indicate that the snowpack is the main source for iodine radicals. The measurements have been performed using multi-axis differential optical absorption spectroscopy (MAX-DOAS). Using a coupled atmosphere-snowpack radiative transfer model, the comparison of the signals observed from scattered skylight and from light reflected by the snowpack yields several ppb of iodine monoxide in the upper layers of the sunlit snowpack throughout the year. Snow pit samples from Neumayer Station contain up to 700 ng/l of total iodine, representing a sufficient reservoir for these extraordinarily high IO concentrations.

Citation: Frieß, U., Deutschmann, T., Gilfedder, B., Weller, R., and Platt, U.: Iodine monoxide in the Antarctic snowpack, Atmos. Chem. Phys. Discuss., 9, 25361-25407, doi:10.5194/acpd-9-25361-2009, 2009.
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