ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-12-6565-2012 Simultaneous satellite observations of IO and BrO over Antarctica Schönhardt A. 1 Begoin M. 1 Richter A. 1 Wittrock F. 1 Kaleschke L. 2 Gómez Martín J. C. 3 Burrows J. P. 1 Institute of Environmental Physics (IUP), University of Bremen, Bremen, Germany KlimaCampus, Institute of Oceanography, University of Hamburg, Hamburg, Germany Laboratory for Atmospheric and Climate Science, CSIC, Toledo, Spain 25 07 2012 12 14 6565 6580 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/12/6565/2012/acp-12-6565-2012.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/12/6565/2012/acp-12-6565-2012.pdf

This article reports on satellite observations of iodine monoxide (IO) and bromine monoxide (BrO). The region of interest is Antarctica in the time between spring and autumn. Both molecules, IO and BrO, are reactive halogen species and strongly influence tropospheric composition. As a result, a better understanding of their spatial distribution and temporal evolution is necessary to assess accurately their role in tropospheric chemistry. Especially in the case of IO, information on its present magnitude, spatial distribution patterns and source regions is still sparse. <br><br> The present study is based on six years of SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY) data recorded in nadir viewing geometry. Multi-year averages of monthly mean IO columns are presented and compared to the distributions of BrO. Influences of the IO air mass factor and the IO absorption cross section temperature dependence on the absolute vertical columns are discussed. The long-term observations of IO and BrO columns yield new insight into the temporal and spatial variation of IO above the Antarctic region. The occurrence of IO on Antarctic sea ice in late spring (November) is discovered and presented. In addition, the comparison between IO and BrO distributions show many differences, which argues for different mechanisms and individual nature of the release of the two halogen oxide precursors. The state of the ecosystem, in particular the changing condition of the sea ice in late spring, is used to explain the observations of the IO behaviour over Antarctica and the differences between IO and BrO distributions.

 References Acker, J. G. and Leptoukh, G.: Online analysis enhances use of NASA earth science data, Eos, Transactions, American Geophysical Union, 88, 14–17, 2007. Alicke,~B., Hebestreit,~K., Stutz,~J., and Platt,~U.: Iodine oxide in the marine boundary layer, Nature, 572, 397–398, 1999. Allan,~B J., McFiggans,~G., Plane,~J M C., and Coe,~H.: Observations of iodine monoxide in the remote marine boundary layer, J. Geophys. Res., 105, 14363–14369, 2000. % Atkinson, H. M., Huang, R.-J., Chance, R., Roscoe, H. K., Hughes, C., Davison, B., Schönhardt, A., Mahajan, A. S., Saiz-Lopez, A., Hoffmann, T., and Liss, P. S.: Iodine emissions from the sea ice of the Weddell Sea, Atmos. Chem. Phys. Discuss., 12, 11595–11639, http://dx.doi.org/10.5194/acpd-12-11595-2012doi:10.5194/acpd-12-11595-2012, 2012. Barrie,~L A., Bottenheim,~J W., Schnell,~R C., Crutzen~P J., and Rasmussen,~R A.: Ozone destruction and photochemical reactions at polar sunrise in the lower Arctic atmosphere, Nature, 334, 138–141, 1988. % Bäumer, D. , Vogel, B., Versick, S., Rinke, R., Möhler, O., and Schnaiter, M.: Relationship of visibility, aerosol optical thickness and aerosol size distribution in an ageing air mass over South-West Germany, Atmos. Env., 42, 989–998, 2008. %% Begoin,~M., Richter,~A., Weber,~M., Kaleschke,~L., Tian-Kunze,~X., Stohl,~A., Theys,~N., and Burrows,~J P.: Satellite observations of long range transport of a large BrO plume in the Arctic, Atmos. Chem. Phys., 10, 6515–6526, http://dx.doi.org/10.5194/acp-10-6515-2010doi:10.5194/acp-10-6515-2010, 2010. %%ok Bloss,~W J., Rowley,~D M., Cox,~R A., and Jones,~R L.: Kinetics and products of the IO self-reaction, J. Phys. Chem. A, 105, 7840–7854, 2001. % Bloss,~W J., Lee,~J D., Johnson,~G P., Sommariva,~R., Heard,~D E., Saiz-Lopez,~A., McFiggans,~G., Coe,~H., Flynn,~M., Williams,~P., Rickard,~A R., and Fleming,~Z L.: Impact of halogen monoxide chemistry upon boundary layer OH and HO<sub>2</sub> concentrations at a coastal site, Geophys. Res. Lett., 32, L06814, http://dx.doi.org/10.1029/2004GL022084doi:10.1029/2004GL022084, 2005. % Bösch,~H., Camy-Peyret,~C., Chipperfield,~M P., Fitzenberger,~R., Harder,~H., Platt,~U., and Pfeilsticker,~K.: Upper limits of stratospheric IO and OIO inferred from center-to-limb-darkening-corrected balloon-borne solar occultation visible spectra: implications for total gaseous iodine and stratospheric ozone, J. Geophys. Res., 108, 4455, http://dx.doi.org/10.1029/2002JD003078doi:10.1029/2002JD003078, 2003. % Bogumil,~K., Orphal,~J., Homann,~T., Voigt,~S., Spietz,~P., Fleischmann,~O C., Vogel,~A., Hartmann,~M., Bovensmann,~H., Frerik,~J., and Burrows,~J P.: Measurements of molecular absorption spectra with the SCIAMACHY Pre-Flight Model: instrument characterization and reference data for atmospheric remote-sensing in the 230–2380 nm Region, J. Photoch. Photobio. A., 157, 167–184, 2003. % Bovensmann,~H., Burrows,~J P., Buchwitz,~M., Frerick,~J., Noël,~S., Rozanov,~V V., Chance,~K V., and Goede,~A P H.: SCIAMACHY: mission objectives and measurement modes, J. Atmos. Sci., 56, 127–150, 1999. % Brune,~W H., Anderson,~J G., and Chan,~K R.: In situ observations of BrO over Antarctica: ER-2 aircraft results from 54\degree S to 72\degree S latitude, J. Geophys. Res., 94, 6639–16647, 1989. % Burkholder,~J B., Curtius,~J., Ravishankara,~A R., and Lovejoy,~E R.: Laboratory studies of the homogeneous nucleation of iodine oxides, Atmos. Chem. Phys., 4, 19–34, http://dx.doi.org/10.5194/acp-4-19-2004doi:10.5194/acp-4-19-2004, 2004. %%ok Burrows,~J P., Hölzle,~E., Goede,~A P H., Visser,~H., and Fricke,~W.: SCIAMACHY – Scanning Imaging Absorption Spectrometer for Atmospheric Chartography, Acta Astronaut., 35, 445–451, 1995. % Butz,~A., Bösch,~H., Camy-Peyret,~C., Chipperfield,~M P., Dorf,~M., Kreycy,~S., Kritten,~L., Prados-Román,~C., Schwärzle,~J., and Pfeilsticker,~K.: Constraints on inorganic gaseous iodine in the tropical upper troposphere and stratosphere inferred from balloon-borne solar occultation observations, Atmos. Chem. Phys., 9, 7229–7242, http://dx.doi.org/10.5194/acp-9-7229-2009doi:10.5194/acp-9-7229-2009, 2009. %%ok Carpenter,~L J.: Iodine in the marine boundary layer, Chem. Rev., 103, 4953–4962, 2003. % Carpenter,~L J., Sturges,~W T., Penkett,~S A., Liss,~P S., Alicke,~B., Hebestreit,~K., and Platt,~U.: Short-lived alkyl iodides and bromides at Mace Head, Ireland: links to biogenic sources and halogen oxide production, J. Geophys. Res., 104, 1679–1689, 1999. % Carpenter,~L J., Wevill,~D J., Palmer,~C J., and Michels,~J.: Depth profiles of volatile iodine and bromine-containing halocarbons in coastal Antarctic waters, Mar. Chem., 103, 227–236, 2007. % Carroll,~M A., Sanders,~R W., Solomon,~S., and Schmeltekopf,~A L.: Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica. 6. observations of BrO, J. Geophys. Res., 94, D14, 16633–16638, 1989. %, Mar. Chem., 103, 227–236, 2007. % Comiso,~J C.: Variability and trends in Antarctic surface temperatures from in situ and satellite infrared measurements, J. Climate, 13, 1674–1696, 2000. % Fleischmann,~O C., Hartmann,~M., Burrows,~J P., and Orphal,~J.: New ultraviolet absorption cross-sections of BrO at atmospheric temperatures measured by a time-windowing Fourier transform spectroscopy, J. Photoch. Photobio. A., 168, 117–132, 2004. % Frieß,~U., Wagner,~T., Pundt,~I., Pfeilsticker,~K., and Platt,~U.: Spectroscopic measurements of tropospheric iodine oxide at Neumeyer station, Antarctica, Geophys. Res. Lett., 28, 1941, http://dx.doi.org/10.1029/2003JD004133doi:10.1029/2003JD004133, 2001. % Frieß,~U., Deutschmann,~T., Gilfedder,~B S., Weller,~R., and Platt,~U.: Iodine monoxide in the Antarctic snowpack, Atmos. Chem. Phys., 10, 2439–2456, http://dx.doi.org/10.5194/acp-10-2439-2010doi:10.5194/acp-10-2439-2010, 2010. %%ok Giese,~B., Laturnus,~F., Adams,~F C., and Wiencke,~C.: Release of volatile iodinated C1–C4 hydrocarbons by marine macroalgae from various climate zones, Environ. Sci. Technol., 33, 2432–2439, 1999. % Golden,~K M., Ackley,~S F., and Lytle,~V I.: The percolation phase transition in sea ice, Science, 282, 2238–2241, http://dx.doi.org/10.1126/science.282.5397.2238doi:10.1126/science.282.5397.2238, 1998. % Gómez Mart\'in,~J C.: Spectroscopic, Kinetic and Mechanistic Studies of Atmospherically Relevant $\chemI_2/O_3$ Photochemistry, Ph.D. Thesis, University Bremen, Germany, 2006. % Gómez Mart\'in,~J C., Spietz,~P., and Burrows,~J P.: Kinetic and mechanistic studies of the \chemI_2/\chemO_3 photochemistry, J. Phys. Chem ~A., 111, 306, http://dx.doi.org/10.1021/jp061186cdoi:10.1021/jp061186c, 2007. % Gómez Mart\'in,~J C., Ashworth,~S H., Mahajan,~A S., and Plane,~J C M.: Photochemistry of OIO: laboratory study and atmospheric implications, Geophys. Res. Lett., 36, L09802, http://dx.doi.org/10.1029/2009GL037642doi:10.1029/2009GL037642, 2009. % Gottwald,~M. and Bovensmann,~H. (Eds.): SCIAMACHY – Exploring the Changing Earth's Atmosphere, ISBN 978-90-481-9895-5, http://dx.doi.org/10.1007/978-90-481-9896-2doi:10.1007/978-90-481-9896-2, Springer, Dordrecht Heidelberg London New York, 2011. % Gottwald,~M., Bovensmann,~H., Lichtenberg,~G., Noel,~S., von Bargen,~A., Slijkhuis,~S., Piters,~A., Hoogeveen,~R., von Savigny,~C., Buchwitz,~M., Kokhanovsky,~A., Richter,~A., Rozanov,~A., Holzer-Popp,~T., Bramstedt,~K., Lambert,~J.-C., Skupin,~J., Wittrock,~F., Schrijver,~H., and Burrows,~J P. (Eds.): SCIAMACHY – Monitoring the Changing Earth's atmosphere, DLR, Institut für Methodik der Fernerkundung (IMF), available online at: http://atmos.caf.dlr.de/projects/scops/sciamachy_book/sciamachy_book_dlr.html, last access: 20 July 2012, 2006. Hausmann,~M. and Platt,~U.: Spectroscopic measurement of bromine oxide and ozone in the high Arctic during Polar Sunrise Experiment 1992, J. Geophys. Res., 99, 25399–25413, 1994. % Himmelmann,~S., Orphal,~J., Bovensmann,~H., Richter,~A., Ladstätter-Weißenmayer,~A., and Burrows,~J P.: First observation of the OIO molecule by time resolved flash photolysis absorption spectroscopy, Chem. Phys. Lett., 251, 330–334, 1996. % Hönninger,~G., Leser,~H., Sebastián,~O., and Platt,~U.: Ground-based measurements of halogen oxides at the Hudson Bay by active longpath DOAS and passive MAX-DOAS, Geophys. Res. Lett., 31, L04111, http://dx.doi.org/10.1029/2003GL018982doi:10.1029/2003GL018982, 2004. % Jimenez,~J L., Bahreini,~R., Cocker~III,~D R., Zhuang,~H., Varutbangkul,~V., Flagan,~R C., and Seinfeld,~J H., O'Dowd,~C D., and Hoffmann,~T.: New particle formation from photooxidation of diiodomethane (\chemCH_2I_2), J Geophys. Res., 108, 4318, doi:10.1029/2002JD002452, 2003. % Kaleschke,~L., Lüpkes,~C., Vihma,~T., Haarpaintner,~J., Bochert,~A., Hartmann,~J., and Heygster,~G.: SSM/I sea ice remote sensing for mesoscale ocean-atmosphere interaction analysis, Can. J. Remote Sens., 27, 526–537, 2001. % Kaleschke,~L., Richter,~A., Burrows,~J P., Afe,~O., Heygster,~G., Notholt,~J., Rankin,~A M., Roscoe,~H K., Hollwedel,~J., Wagner,~T., and Jacobi,~H.-W.: Frost flowers on sea ice as a source of sea salt and their influence on tropospheric halogen chemistry, Geophys. Res. Lett., 31, L16114, http://dx.doi.org/10.1029/2004GL020655doi:10.1029/2004GL020655, 2004. % Kreher,~K., Johnston,~P V., Wood,~S W., Nardi,~B., and Platt,~U.: Ground-based measurements of tropospheric and stratospheric BrO at Arrival Heights, Antarctica, Geophys. Res. Lett., 24, 3021–3024, 1997. % Mahajan,~A S., Shaw,~M., Oetjen,~H., Hornsby,~K E., Carpenter,~L J., Kaleschke,~L., Tian-Kunze,~X., Lee,~J D., Moller,~S J., Edwards,~P., Commane,~R., Ingham,~T., Heard,~D E., and Plane,~J M C.: Evidence of reactive iodine chemistry in the Arctic boundary layer, J. Geophys. Res., 115, D20303, http://dx.doi.org/10.1029/2009JD013665doi:10.1029/2009JD013665, 2010. % McFiggans,~G., Coe,~H., Burgess,~R., Allan,~J., Cubison,~M., Alfarra,~M R., Saunders,~R., Saiz-Lopez,~A., Plane,~J M C., Wevill,~D., Carpenter,~L., Rickard,~A R., and Monks,~P S.: Direct evidence for coastal iodine particles from Laminaria macroalgae – linkage to emissions of molecular iodine, Atmos. Chem. Phys., 4, 701–713, http://dx.doi.org/10.5194/acp-4-701-2004doi:10.5194/acp-4-701-2004, 2004. %%ok Miller,~H L., Weaver,~A., Sanders,~R W., Arpag,~K., and Solomon,~S.: Measurements of Arctic sunrise surface ozone depletion events at Kangerlussuaq, Greenland (67\degree N, 51\degree W), Tellus B, 49, 496–509, 1997. % Moore,~R M., Webb,~M., Tokarczyk,~R., and Wever,~R.: Bromoperoxidase and iodoperoxidase enzymes and production of halogenated methanes in marine diatom cultures, J. Geophys. Res., 101, 20899–20908, 1996. % Oetjen,~H.: Measurements of halogen oxides by scattered sunlight differential optical absorption spectroscopy, Ph.D. Thesis, University Bremen, Germany, 2009. % O'Dowd,~C D. and Hoffmann,~T.: Coastal new particle formation: a review of the current state-of-the-art, Environ. Chem., 2, 245, http://dx.doi.org/10.1071/EN05077doi:10.1071/EN05077, 2005. % O'Dowd,~C D., Jimenez,~J L., Bahreini,~R., Flagan,~R C., Seinfeld,~J H., Hameri,~K., Pirjola,~L., Kulmala,~M., Jennings,~S G., and Hoffmann,~T.: Marine aerosol formation from biogenic iodine emissions, Nature, 417, 632–636, 2002. % Pedersén,~M., Collén,~J., Abrahamsson,~K., and Ekdahl,~A.: Production of halocarbons by seaweeds: an oxidative stress reaction?, Sci. Mar., 60, 257–263, 1996. % Peters,~C., Pechtl,~S., Stutz,~J., Hebestreit,~K., Hönninger,~G., Heumann,~K G., Schwarz,~A., Winterlik,~J., and Platt,~U.: Reactive and organic halogen species in three different European coastal environments, Atmos. Chem. Phys., 5, 3357–3375, http://dx.doi.org/10.5194/acp-5-3357-2005doi:10.5194/acp-5-3357-2005, 2005. %%ok Platt,~U. and von Glasow,~R.: Halogens in the troposphere – an international task, Science and Implementation Plan, Geophys. Res. Abstr., 7, 07581, White Paper, available online at: www.uea.ac.uk/~fkd06bju/HitT/HitT_WhitePaper.pdf, last access: 20 July 2012, 2005. Platt,~U. and Hönninger,~G.: The role of halogen species in the troposphere, Chemosphere, 52, 325–338, 2003. % Platt,~U. and Perner,~D.: Direct measurements of atmospheric CH<sub>2</sub>O, HNO<sub>2</sub>, O<sub>3</sub>, NO<sub>2</sub>, SO<sub>2</sub> by differential optical absorption in the near UV, J. Geophys. Res., 85, C12, 7453–7458, 1980. % Platt,~U. and Stutz,~J.: Differential Optical Absorption Spectroscopy – Principles and Applications, Springer-Verlag, Berlin Heidelberg, ISBN 978-3-540-21193-8, 2008. % Pundt,~I., Pommereau,~J.-P., Phillips,~C., and Lateltin,~E.: Upper limits of iodine oxide in the lower stratosphere, J. Atmos. Chem., 30, 173–185, 1998. % Read,~K A., Mahajan,~A S., Carpenter,~L J., Evans,~M J., Faria,~B V E., Heard,~D E., Hopkins,~J R., Lee,~J D., Moller,~S J., Lewis,~A C., Mendes,~L., McQuaid,~J B., Oetjen,~H., Saiz-Lopez,~A., Pilling,~M J., and Plane,~J M C.: Extensive halogen-mediated ozone destruction over the tropical Atlantic Ocean, Nature, 453, 1232–1235, http://dx.doi.org/10.1038/nature07035doi:10.1038/nature07035, 2008. % Richter,~A., Wittrock,~F., Eisinger,~M., and Burrows,~J P.: GOME observations of tropospheric BrO in Northern Hemispheric spring and summer 1997, Geophys. Res. Lett., 25, 2683–2686, 1998. % Richter,~A., Wittrock,~F., Ladstätter-Weißenmayer,~A., and Burrows,~J P.: GOME measurements of stratospheric and tropospheric BrO, Adv. Space Res., 29, 11, 1667–1672, 2002. % Rozanov,~A., Rozanov,~V.-V., Buchwitz,~M., Kokhanovsky,~A., and Burrows,~J P.: SCIATRAN 2.0. A new radiative transfer model for geophysical applications in the 175–2400 nm spectral region, Adv. Space Res., 36, 1015–1019, http://dx.doi.org/10.1016/j.asr.2005.03.012doi:10.1016/j.asr.2005.03.012, 2005a. % Rozanov,~A., Bovensmann,~H., Bracher,~A., Hrechanyy,~S., Rozanov,~V., Sinnhuber,~M., Stroh,~F., and Burrows,~J P.: NO<sub>2</sub> and BrO vertical profile retrieval from SCIAMACHY limb measurements: sensitivity studies, Adv. Space Res., 36, 846–854, 2005b. % Rozanov,~V V., Buchwitz,~M., Eichmann,~K.-U., de Beek,~R., and Burrows,~J P.: Sciatran – a new radiative transfer model for geophysical applications in the 240–2400 nm spectral region: the Pseudo-spherical version, Adv. Space Res., 29, 1831–1835, 2002. % Saiz-Lopez, A. and Boxe, C. S.: A mechanism for biologically-induced iodine emissions from sea-ice, Atmos. Chem. Phys. Discuss., 8, 2953–2976, http://dx.doi.org/10.5194/acpd-8-2953-2008doi:10.5194/acpd-8-2953-2008, 2008. Saiz-Lopez,~A., Shillito,~J A., Coe,~H., and Plane,~J M C.: Measurements and modelling of I<sub>2</sub>, IO, OIO, BrO and NO<sub>3</sub> in the mid-latitude marine boundary layer, Atmos. Chem. Phys., 6, 1513–1528, http://dx.doi.org/10.5194/acp-6-1513-2006doi:10.5194/acp-6-1513-2006, 2006. %%ok Saiz-Lopez,~A., Mahajan,~A S., Salmon,~R A., Bauguitte,~S J.-B., Jones,~A E., Roscoe,~H K., and Plane,~J M C.: Boundary layer halogens in coastal Antarctica, Science, 317, 348–351, http://dx.doi.org/10.1126/science.1141408doi:10.1126/science.1141408, 2007a. % Saiz-Lopez,~A., Chance,~K., Liu,~X., Kurosu,~T P., and Sander,~S P.: First observations of iodine oxide from space, Geophys. Res. Lett., 34, L12812, http://dx.doi.org/10.1029/2007GL030111doi:10.1029/2007GL030111, 2007b. % Saiz-Lopez,~A., Plane,~J M C., Mahajan,~A S., Anderson,~P S., Bauguitte,~ S J.-B., Jones,~A E., Roscoe,~H K., Salmon,~R A., Bloss,~W J., Lee,~J D., and Heard,~D E.: On the vertical distribution of boundary layer halogens over coastal Antarctica: implications for O<sub>3</sub>, HO<sub>x</sub>, NO<sub>x</sub> and the Hg lifetime, Atmos. Chem. Phys., 8, 887–900, http://dx.doi.org/10.5194/acp-8-887-2008doi:10.5194/acp-8-887-2008, 2008. %%ok Saiz-Lopez,~A., Ordoñez,~C., Gomez Martin,~J. C., Lamarque,~J.-F., and Kinnison,~D. E.: Global modelling of upper tropospheric-lower stratospheric iodine: budget and implications for ozone, Geophysical Research Abstracts, Vol. 14, EGU2012-8580, EGU General Assembly, 2012. % 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, http://dx.doi.org/10.5194/acp-6-4653-2006doi:10.5194/acp-6-4653-2006, 2006. %%ok Saunders,~R. W., Kumar,~R., Gomez-Martin,~J. C., Mahajan,~A. S., Murray,~B. J., and Plane,~J. M. C.: Studies of the formation and growth of aerosol from molecular iodine precursor, Z. Phys. Chem., 224, 1095–1117, doi:10.1524/zpch.2010.6143, 2010. Schönhardt,~A., Richter,~A., Wittrock,~F., Kirk,~H., Oetjen,~H., Roscoe,~H K., and Burrows,~J P.: Observations of iodine monoxide columns from satellite, Atmos. Chem. Phys., 8, 637–653, http://dx.doi.org/10.5194/acp-8-637-2008doi:10.5194/acp-8-637-2008, 2008. %% Schönhardt,~A., Richter,~A., and Burrows,~J P.: Iodine Monoxide and the relations to sea ice and biological activity, Proc. of ESA, SOLAS & EGU Joint Conference "Earth Observation for Ocean-Atmosphere Interactions Science" Frascati, Italy, 29~November - 2~December 2011, ESA SP-703, March 2012. % Schroeder,~W H., Anlauf,~K G., Barrie,~L A., Lu,~J Y., Steffen,~A., Schneeberger,~D R., and Berg,~T.: Arctic springtime depletion of mercury, Nature, 394, 331–332, 1998. % Shaw, G. E.: Antarctic aerosols: A review, Rev. Geophys., 26, 89–112, 1988. %% Simpson,~W R., Carlson,~D., Hönninger,~G., Douglas,~T A., Sturm,~M., Perovich,~D., and Platt,~U.: First-year sea-ice contact predicts bromine monoxide (BrO) levels at Barrow, Alaska better than potential frost flower contact, Atmos. Chem. Phys., 7, 621–627, http://dx.doi.org/10.5194/acp-7-621-2007doi:10.5194/acp-7-621-2007, 2007a. %%ok Simpson,~W R., von Glasow,~R., Riedel,~K., Anderson,~P., Ariya,~P., Bottenheim,~J., Burrows,~J., Carpenter,~L J., Frieß,~U., Goodsite,~M E., Heard,~D., Hutterli,~M., Jacobi,~H.-W., Kaleschke,~L., Neff,~B., Plane,~J., Platt,~U., Richter,~A., Roscoe,~H., Sander,~R., Shepson,~P., Sodeau,~J., Steffen,~A., Wagner,~T., and Wolff,~E.: Halogens and their role in polar boundary-layer ozone depletion, Atmos. Chem. Phys., 7, 4375–4418, http://dx.doi.org/10.5194/acp-7-4375-2007doi:10.5194/acp-7-4375-2007, 2007b. Solomon,~S., Sanders,~R W., Carroll,~M A., and Schmeltekopf,~A L.: Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica. 5. Observations of the diurnal variations of BrO and OClO, J. Geophys. Res., 94, D9, 11393–11403, 1989. % Solomon,~S., Garcia,~R R., and Ravishankara,~A R.: On the role of iodine in ozone depletion, J. Geophys. Res., 99, 20491–20499, 1994. % Spreen,~G., Kaleschke,~L., and Heygster,~G.: Sea ice remote sensing using AMSR-E 89~GHz channels, J. Geophys. Res., 113, C02S03, http://dx.doi.org/10.1029/2005JC00338doi:10.1029/2005JC00338, 2008. % Steffen,~A., Douglas,~T., Amyot,~M., Ariya,~P., Aspmo,~K., Berg,~T., Bottenheim,~J., Brooks,~S., Cobbett,~F., Dastoor,~A., Dommergue,~A., Ebinghaus,~R., Ferrari,~C., Gardfeldt,~K., Goodsite,~M E., Lean,~D., Poulain,~A J., Scherz,~C., Skov,~H., Sommar,~J., and Temme,~C.: A synthesis of atmospheric mercury depletion event chemistry in the atmosphere and snow, Atmos. Chem. Phys., 8, 1445–1482, http://dx.doi.org/10.5194/acp-8-1445-2008doi:10.5194/acp-8-1445-2008, 2008. %%ok Theys,~N., Van Roozendael,~M., Hendrick,~F., Yang,~X., De Smedt,~I., Richter,~A., Begoin,~M., Errera,~Q., Johnston,~P V., Kreher,~K., and De Mazière,~M.: Global observations of tropospheric BrO columns using GOME-2 satellite data, Atmos. Chem. Phys., 11, 1791–1811, http://dx.doi.org/10.5194/acp-11-1791-2011doi:10.5194/acp-11-1791-2011, 2011. %%ok \hack Thomas,~D N. and Diekmann,~G S. (Eds.): Sea Ice: An introduction to its physics, chemistry, biology and geology, Blackwell Publishing Company, Oxford, UK, 2003. % Tokarczyk,~R. and Moore,~R M.: Production of volatile organohalogens by phytoplankton cultures, Geophys. Res. Lett., 21, 4, 285–288, 1994. % Vogt,~R., Sander,~R., von Glasow,~R., and Crutzen,~P J.: Iodine chemistry and its role in halogen activation and ozone loss in the marine boundary layer: a model study., J. Atmos. Chem., 32, 375–395, 1999. % Volkamer,~R., Coburn,~S., Dix,~B., Sinreich,~R., Lechner,~M., Atlas,~E., Guenther,~A., Duhl,~T., Sommariva,~R., von~Glasow,~R., Myriokefalitakis,~S., and Kanakidou,~M.: Controls from a widespread surface ocean organic micro layer on atmospheric oxidative capacity, Geophysical Research Abstracts, 14, EGU2012-6761-1, EGU General Assembly, 2012. % Vountas,~M., Rozanov,~V V., and Burrows,~J P.: Ring effect: impact of rotational Raman scattering on radiative transfer in Earth's atmosphere, J. Quant. Spectrosc. Ra., 60, 943–961, 1998. % Wada,~R., Beames,~J M., and Orr-Ewing,~A J.: Measurement of IO radical concentrations in the marine boundary layer using a cavity ring-down spectrometer, J. Atmos. Chem., 58, 69–87, http://dx.doi.org/10.1007/s10874-007-9080-zdoi:10.1007/s10874-007-9080-z, 2007. % Wagner,~T. and Platt,~U.: Satellite mapping of enhanced BrO concentration in the troposphere, Nature, 395, 486–490, 1998. % Wagner,~T., Leue,~C., Wenig,~M., Pfeilsticker,~K., and Platt,~U.: Spatial and temporal distribution of enhanced boundary layer BrO concentrations measured by the GOME instrument aboard ERS-2, J. Geophys. Res., 106, D20, 24225–24235, 2001. % Whalley,~L K., Furneaux,~K L., Gravestock,~T., Atkinson,~H M., Bale,~C S E., Ingham,~T., Bloss,~W J., and Heard,~D E.: Detection of iodine monoxide radicals in the marine boundary layer using laser induced fluorescence spectroscopy, J. Atmos. Chem., 58, 19–39, http://dx.doi.org/10.1007/s10874-007-9075-9doi:10.1007/s10874-007-9075-9, 2007. % Wittrock,~F., Eisinger,~M., Ladstätter-Weißenmayer,~A., Richter,~A., and Burrows,~J P.: Ground-based UV/VIS measurements of O<sub>3</sub>, NO<sub>2</sub>, BrO, and OClO over Ny-Ålesund (79\degree N, 12\degree E), in: Proc. XVIII Quadrennial Ozone Symposium, L'Aquila, Italy, September 1996, 2, 623–626, 1996. % Wittrock,~F., Müller,~R., Richter,~A., Bovensmann,~H., and Burrows,~J P.: Measurements of iodine monoxide (IO) above Spitsbergen, Geophys. Res. Lett., 27, 1471–1474, 2000. %