ACP Atmospheric Chemistry and Physics ACP Atmos. Chem. Phys. 1680-7324 Copernicus Publications Göttingen, Germany 10.5194/acp-14-4875-2014 Temporal and spatial characteristics of ozone depletion events from measurements in the Arctic Halfacre J. W. https://orcid.org/0000-0002-2977-4507 1 Knepp T. N. https://orcid.org/0000-0003-0326-029X 10 1 Shepson P. B. 1 2 Thompson C. R. 11 1 Pratt K. A. https://orcid.org/0000-0003-4707-2290 1 12 Li B. 3 13 Peterson P. K. https://orcid.org/0000-0002-9337-6677 4 Walsh S. J. 4 Simpson W. R. https://orcid.org/0000-0002-8596-7290 4 Matrai P. A. https://orcid.org/0000-0003-1656-5519 5 Bottenheim J. W. 6 Netcheva S. 7 Perovich D. K. 8 Richter A. https://orcid.org/0000-0003-3339-212X 9 Department of Chemistry, Purdue University, West Lafayette, Indiana, USA Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, USA Department of Statistics, Purdue University, West Lafayette, Indiana, USA Department of Chemistry, University of Alaska, Fairbanks, Alaska, USA Bigelow Laboratory for Ocean Sciences, East Boothbay, Maine, USA Air Quality Research Division, Environment Canada, Toronto, Ontario, Canada Air Quality Processes Research Section, Environment Canada, Toronto, Ontario, Canada US Army Cold Regions Research and Engineering Laboratory, Fairbanks, Alaska, USA Institute of Environmental Physics, University of Bremen, Bremen, Germany now at: Science Systems and Applications, Inc., Hampton, Virginia, USA now at: Institute of Arctic and Alpine Research, University of Colorado at Boulder, Boulder, Colorado, USA now at: Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA now at: Department of Statistics, University Illinois at Urbana-Champaign, Urbana, Illinois, USA 20 05 2014 14 10 4875 4894 Copyright: © 2014 J. W. Halfacre et al. 2014 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://acp.copernicus.org/articles/14/4875/2014/acp-14-4875-2014.html The full text article is available as a PDF file from https://acp.copernicus.org/articles/14/4875/2014/acp-14-4875-2014.pdf

Following polar sunrise in the Arctic springtime, tropospheric ozone episodically decreases rapidly to near-zero levels during ozone depletion events (ODEs). Many uncertainties remain in our understanding of ODE characteristics, including the temporal and spatial scales, as well as environmental drivers. Measurements of ozone, bromine monoxide (BrO), and meteorology were obtained during several deployments of autonomous, ice-tethered buoys (O-Buoys) from both coastal sites and over the Arctic Ocean; these data were used to characterize observed ODEs. Detected decreases in surface ozone levels during the onset of ODEs corresponded to a median estimated apparent ozone depletion timescale (based on both chemistry and the advection of O<sub>3</sub>-depleted air) of 11 h. If assumed to be dominated by chemical mechanisms, these timescales would correspond to larger-than-observed BrO mole fractions based on known chemistry and assumed other radical levels. Using backward air mass trajectories and an assumption that transport mechanisms dominate observations, the spatial scales for ODEs (defined by time periods in which ozone levels ≤15 nmol mol<sup>−1</sup>) were estimated to be 877 km (median), while areas estimated to represent major ozone depletions (<10 nmol mol<sup>−1</sup>) had dimensions of 282 km (median). These observations point to a heterogeneous boundary layer with localized regions of active, ozone-destroying halogen chemistry, interspersed among larger regions of previously depleted air that retain reduced ozone levels through hindered atmospheric mixing. Based on the estimated size distribution, Monte Carlo simulations showed it was statistically possible that all ODEs observed could have originated upwind, followed by transport to the measurement site. Local wind speed averages were low during most ODEs (median of ~3.6 m s<sup>−1</sup>), and there was no apparent dependence on local temperature.

 References Abbatt, J. P. D., Thomas, J. L., Abrahamsson, K., Boxe, C., Granfors, A., Jones, A. E., King, M. D., Saiz-Lopez, A., Shepson, P. B., Sodeau, J., Toohey, D. W., Toubin, C., von Glasow, R., Wren, S. N., and Yang, X.: Halogen activation via interactions with environmental ice and snow in the polar lower troposphere and other regions, Atmos. Chem. Phys., 12, 6237–6271, <a href="http://dx.doi.org/10.5194/acp-12-6237-2012">https://doi.org/10.5194/acp-12-6237-2012</a>, 2012. Adams, J. W., Holmes, N. S., and Crowley, J. N.: Uptake and reaction of HOBr on frozen and dry NaCl / NaBr surfaces between 253 and 233 K, Atmos. Chem. Phys., 2, 79–91, <a href="http://dx.doi.org/10.5194/acp-2-79-2002">https://doi.org/10.5194/acp-2-79-2002</a>, 2002. Aguzzi, A. and Rossi, M. J.: Heterogeneous hydrolysis and reaction of BrONO<sub>2</sub> and Br<sub>2</sub>O on pure ice and ice doped with HBr, J. Phys. Chem. A, 106, 5891–5901, <a href="http://dx.doi.org/10.1021/Jp014383e">https://doi.org/10.1021/Jp014383e</a>, 2002. Albert, M. R., Grannas, A. M., Bottenheim, J., Shepson, P. B., and Perron, F. E.: Processes and properties of snow–air transfer in the high Arctic with application to interstitial ozone at Alert, Canada, Atmos. Environ., 36, 2779–2787, <a href="http://dx.doi.org/10.1016/s1352-2310(02)00118-8">https://doi.org/10.1016/s1352-2310(02)00118-8</a>, 2002. Anlauf, K. G., Mickle, R. E., and Trivett, N. B. A.: Measurement of Ozone during Polar Sunrise Experiment 1992, J. Geophys. Res., 99, 25345–25353, <a href="http://dx.doi.org/10.1029/94jd01312">https://doi.org/10.1029/94jd01312</a>, 1994. Atkinson, R., Baulch, D. L., Cox, R. A., Crowley, J. N., Hampson, R. F., Hynes, R. G., Jenkin, M. E., Rossi, M. J., and Troe, J.: Evaluated kinetic and photochemical data for atmospheric chemistry: Volume III – gas phase reactions of inorganic halogens, Atmos. Chem. Phys., 7, 981–1191, <a href="http://dx.doi.org/10.5194/acp-7-981-2007">https://doi.org/10.5194/acp-7-981-2007</a>, 2007. 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. Barrie, L. A., Staebler, R., Toom, D., Georgi, B., Denhartog, G., Landsberger, S., and Wu, D.: Arctic Aerosol Size-Segregated Chemical Observations in Relation to Ozone Depletion during Polar Sunrise Experiment 1992, J. Geophys. Res., 99, 25439–25451, <a href="http://dx.doi.org/10.1029/94jd01514">https://doi.org/10.1029/94jd01514</a>, 1994. Bottenheim, J. W., Gallant, A. G., and Brice, K. A.: Measurements of NO<i><sup>y</sup></i> species and O<sub>3</sub> at 82° N latitude, Geophys. Res. Lett., 13, 113–116, <a href="http://dx.doi.org/10.1029/GL013i002p00113">https://doi.org/10.1029/GL013i002p00113</a>, 1986. Bottenheim, J. W., Fuentes, J. D., Tarasick, D. W., and Anlauf, K. G.: Ozone in the Arctic lower troposphere during winter and spring 2000 (ALERT2000), Atmos. Environ., 36, 2535-2544, <a href="http://dx.doi.org/10.1016/s1352-2310(02)00121-8">https://doi.org/10.1016/s1352-2310(02)00121-8</a>, 2002. Bottenheim, J. W. and Chan, E.: A trajectory study into the origin of spring time Arctic boundary layer ozone depletion, J. Geophys. Res., 111, D19301, <a href="http://dx.doi.org/10.1029/2006jd007055">https://doi.org/10.1029/2006jd007055</a>, 2006. Bottenheim, J. W., Netcheva, S., Morin, S., and Nghiem, S. V.: Ozone in the boundary layer air over the Arctic Ocean: measurements during the TARA transpolar drift 2006–2008, Atmos. Chem. Phys., 9, 4545–4557, <a href="http://dx.doi.org/10.5194/acp-9-4545-2009">https://doi.org/10.5194/acp-9-4545-2009</a>, 2009. Boudries, H. and Bottenheim, J. W.: Cl and Br atom concentrations during a surface boundary layer ozone depletion event in the Canadian high Arctic, Geophys. Res. Lett., 27, 517–520, <a href="http://dx.doi.org/10.1029/1999gl011025">https://doi.org/10.1029/1999gl011025</a>, 2000. Calvert, J. G. and Lindberg, S. E.: Potential influence of iodine-containing compounds on the chemistry of the troposphere in the polar spring. I. Ozone depletion, Atmos. Environ., 38, 5087–5104, <a href="http://dx.doi.org/10.1016/j.atmosenv.2004.05.049">https://doi.org/10.1016/j.atmosenv.2004.05.049</a>, 2004. Carlson, D., Donohoue, D., Platt, U., and Simpson, W. R.: A low power automated MAX-DOAS instrument for the Arctic and other remote unmanned locations, Atmos. Meas. Tech., 3, 429–439, <a href="http://dx.doi.org/10.5194/amt-3-429-2010">https://doi.org/10.5194/amt-3-429-2010</a>, 2010. Cavender, A. E., Biesenthal, T. A., Bottenheim, J. W., and Shepson, P. B.: Volatile organic compound ratios as probes of halogen atom chemistry in the Arctic, Atmos. Chem. Phys., 8, 1737–1750, <a href="http://dx.doi.org/10.5194/acp-8-1737-2008">https://doi.org/10.5194/acp-8-1737-2008</a>, 2008. Cho, H., Shepson, P. B., Barrie, L. A., Cowin, J. P., and Zaveri, R.: NMR investigation of the quasi-brine layer in ice/brine mixtures, J. Phys. Chem. B, 106, 11226–11232, <a href="http://dx.doi.org/10.1021/Jp020449">https://doi.org/10.1021/Jp020449</a>, 2002. Choi, S., Wang, Y., Salawitch, R. J., Canty, T., Joiner, J., Zeng, T., Kurosu, T. P., Chance, K., Richter, A., Huey, L. G., Liao, J., Neuman, J. A., Nowak, J. B., Dibb, J. E., Weinheimer, A. J., Diskin, G., Ryerson, T. B., da Silva, A., Curry, J., Kinnison, D., Tilmes, S., and Levelt, P. F.: Analysis of satellite-derived Arctic tropospheric BrO columns in conjunction with aircraft measurements during ARCTAS and ARCPAC, Atmos. Chem. Phys., 12, 1255–1285, <a href="http://dx.doi.org/10.5194/acp-12-1255-2012">https://doi.org/10.5194/acp-12-1255-2012</a>, 2012. Deutschmann, T., Beirle, S., Frieß, U., Grzegorski, M., Kern, C., Kritten, L., Platt, U., Prados-Román, C., Puķīte, J., Wagner, T., Werner, B., and Pfeilsticker, K.: The Monte Carlo atmospheric radiative transfer model McArtim: Introduction and validation of Jacobians and 3D features, J. Quant. Spectrosc. Radiat. Transfer, 112, 1119–1137, 2011. Draxler, R. R. and Hess, G. D.: Description of the HYSPLIT 4 modeling system. NOAA Tech. Memo. ERL ARL-224, NOAA Air Resources Laboratory, Silver Spring, MD, 1997. Draxler, R. R. and Hess, G. D.: An overview of the HYSPLIT 4 modeling system of trajectories, dispersion, and deposition, Aust. Meteor. Mag., 47, 295–308, 1998. Draxler, R. R.: HYSPLIT 4 users's guide, U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Air Resources Laboratory, Silver Spring, MD, 1–209, 1999. Fan, S. M. and Jacob, D. J.: Surface Ozone Depletion in Arctic Spring Sustained by Bromine Reactions on Aerosols, Nature, 359, 522–524, <a href="http://dx.doi.org/10.1038/359522a0">https://doi.org/10.1038/359522a0</a>, 1992. Fayt, C., De Smedt, I., Letocart, V., Merlaud, A., Pinardi, G., and Van Roozendael, M.: QDOAS Software User Manual, Belgian Institute for Space Aeronomy, 2011. Foster, K. L., Plastridge, R. A., Bottenheim, J. W., Shepson, P. B., Finlayson-Pitts, B. J., and Spicer, C. W.: The role of Br<sub>2</sub> and BrCl in surface ozone destruction at polar sunrise, Science, 291, 471–474, <a href="http://dx.doi.org/10.1126/science.291.5503.471">https://doi.org/10.1126/science.291.5503.471</a>, 2001. Frieß, U., Monks, P. S., Remedios, J. J., Rozanov, A., Sinreich, R., Wagner, T., and Platt, U.: MAX-DOAS O<sub>4</sub> measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies, J. Geophys. Res., 111, D14203, <a href="http://dx.doi.org/10.1029/2005JD006618">https://doi.org/10.1029/2005JD006618</a>, 2006.. Frieß, U., Sihler, H., Sander, R., Pöhler, D., Yilmaz, S., and Platt, U.: The vertical distribution of BrO and aerosols in the Arctic: Measurements by active and passive differential optical absorption spectroscopy, J. Geophys. Res., 116, D00R04, <a href="http://dx.doi.org/10.1029/2011JD015938">https://doi.org/10.1029/2011JD015938</a>, 2011. Gauss, M., Myhre, G., Isaksen, I. S. A., Grewe, V., Pitari, G., Wild, O., Collins, W. J., Dentener, F. J., Ellingsen, K., Gohar, L. K., Hauglustaine, D. A., Iachetti, D., Lamarque, J. F., Mancini, E., Mickley, L. J., Prather, M. J., Pyle, J. A., Sanderson, M. G., Shine, K. P., Stevenson, D. S., Sudo, K., Szopa, S., and Zeng, G.: Radiative forcing since preindustrial times due to ozone change in the troposphere and the lower stratosphere, Atmos. Chem. Phys., 6, 575–599, <a href="http://dx.doi.org/10.5194/acp-6-575-2006">https://doi.org/10.5194/acp-6-575-2006</a>, 2006. Gilman, J. B., Burkhart, J. F., Lerner, B. M., Williams, E. J., Kuster, W. C., Goldan, P. D., Murphy, P. C., Warneke, C., Fowler, C., Montzka, S. A., Miller, B. R., Miller, L., Oltmans, S. J., Ryerson, T. B., Cooper, O. R., Stohl, A., and de Gouw, J. A.: Ozone variability and halogen oxidation within the Arctic and sub-Arctic springtime boundary layer, Atmos. Chem. Phys., 10, 10223-10236, <a href="http://dx.doi.org/10.5194/acp-10-10223-2010">https://doi.org/10.5194/acp-10-10223-2010</a>, 2010. Hanson, D. R. and Ravishankara, A. R.: Heterogeneous Chemistry of Bromine Species in Sulfuric-Acid under Stratospheric Conditions, Geophys. Res. Lett., 22, 385–388, <a href="http://dx.doi.org/10.1029/94GL03379">https://doi.org/10.1029/94GL03379</a>, 1995. 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, <a href="http://dx.doi.org/10.1029/94jd01314">https://doi.org/10.1029/94jd01314</a>, 1994. Helmig, D., Cohen, L. D., Bocquet, F., Oltmans, S., Grachev, A., and Neff, W.: Spring and summertime diurnal surface ozone fluxes over the polar snow at Summit, Greenland, Geophys. Res. Lett., 36, L08809, <a href="http://dx.doi.org/10.1029/2008GL036549">https://doi.org/10.1029/2008GL036549</a>, 2009. Helmig, D., Boylan, P., Johnson, B., Oltmans, S., Fairall, C., Staebler, R., Weinheimer, A., Orlando, J., Knapp, D. J., Montzka, D. D., Flocke, F., Frieß, U., Sihler, H., and Shepson, P. B.: Ozone dynamics and snow-atmosphere exchanges during ozone depletion events at Barrow, Alaska, J. Geophys. Res., 117, D20303, <a href="http://dx.doi.org/10.1029/2012jd017531">https://doi.org/10.1029/2012jd017531</a>, 2012. 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, <a href="http://dx.doi.org/10.1029/2003GL018982">https://doi.org/10.1029/2003GL018982</a>, 2004a. Hönninger, G., von Friedeburg, C., and Platt, U.: Multi axis differential optical absorption spectroscopy (MAX-DOAS), Atmos. Chem. Phys., 4, 231–254, <a href="http://dx.doi.org/10.5194/acp-4-231-2004">https://doi.org/10.5194/acp-4-231-2004</a>, 2004b. Hopper, J. F., Peters, B., Yokouchi, Y., Niki, H., Jobson, B. T., Shepson, P. B., and Muthuramu, K.: Chemical and Meteorological Observations at Ice Camp Swan during Polar Sunrise Experiment 1992, J. Geophys. Res., 99, 25489–25498, <a href="http://dx.doi.org/10.1029/94JD02303">https://doi.org/10.1029/94JD02303</a>, 1994. Hopper, J. F., Barrie, L. A., Silis, A., Hart, W., Gallant, A. J., and Dryfhout, H.: Ozone and meteorology during the 1994 Polar Sunrise Experiment, J. Geophys. Res., 103, 1481–1492, 1998. Huff, A. K., and Abbatt, J. P. D.: Kinetics and product yields in the heterogeneous reactions of HOBr with ice surfaces containing NaBr and NaCl, J. Phys. Chem. A, 106, 5279–5287, <a href="http://dx.doi.org/10.1021/Jp014296m">https://doi.org/10.1021/Jp014296m</a>, 2002. Hutterli, M. A., McConnell, J. R., Stewart, R. W., Jacobi, H. W., and Bales, R. C.: Impact of temperature-driven cycling of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) between air and snow on the planetary boundary layer, J. Geophys. Res., 106, 15395–15404, <a href="http://dx.doi.org/10.1029/2001jd900102">https://doi.org/10.1029/2001jd900102</a>, 2001. Jacobi, H. W., Frey, M. M., Hutterli, M. A., Bales, R. C., Schrems, O., Cullen, N. J., Steffen, K., and Koehler, C.: Measurements of hydrogen peroxide and formaldehyde exchange between the atmosphere and surface snow at Summit, Greenland, Atmos. Environ., 36, 2619–2628, <a href="http://dx.doi.org/10.1016/S1352-2310(02)00106-1">https://doi.org/10.1016/S1352-2310(02)00106-1</a>, 2002. Jacobi, H. W., Kaleschke, L., Richter, A., Rozanov, A., and Burrows, J. P.: Observation of a fast ozone loss in the marginal ice zone of the Arctic Ocean, J. Geophys. Res., 111, D15309, <a href="http://dx.doi.org/10.1029/2005jd006715">https://doi.org/10.1029/2005jd006715</a>, 2006. Jacobi, H. W., Morin, S., and Bottenheim, J. W.: Observation of widespread depletion of ozone in the springtime boundary layer of the central Arctic linked to mesoscale synoptic conditions, J. Geophys. Res., 115, D17302, <a href="http://dx.doi.org/10.1029/2010jd013940">https://doi.org/10.1029/2010jd013940</a>, 2010. Jaeschke, W., Salkowski, T., Dierssen, J. P., Trumbach, J. V., Krischke, U., and Günther, A.: Measurements of trace substances in the Arctic troposphere as potential precursors and constituents of Arctic haze, J. Atmos. Chem., 34, 291–319, 1999. Jobson, B. T., Niki, H., Yokouchi, Y., Bottenheim, J., Hopper, F., and Leaitch, R.: Measurements of C<sub>2</sub>–C<sub>6</sub> Hydrocarbons during the Polar Sunrise 1992 Experiment – Evidence for Cl atom and Br atom Chemistry, J. Geophys. Res., 99, 25355–25368, <a href="http://dx.doi.org/10.1029/94JD01243">https://doi.org/10.1029/94JD01243</a>, 1994. 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., 9, 4639–4652, <a href="http://dx.doi.org/10.5194/acp-9-4639-2009">https://doi.org/10.5194/acp-9-4639-2009</a>, 2009. Jones, A. E., Wolff, E. W., Brough, N., Bauguitte, S. J. B., Weller, R., Yela, M., Navarro-Comas, M., Ochoa, H. A., and Theys, N.: The spatial scale of ozone depletion events derived from an autonomous surface ozone network in coastal Antarctica, Atmos. Chem. Phys., 13, 1457–1467, <a href="http://dx.doi.org/10.5194/acp-13-1457-2013">https://doi.org/10.5194/acp-13-1457-2013</a>, 2013. Kahl, J. D.: A Cautionary Note on the Use of Air Trajectories in Interpreting Atmospheric Chemistry Measurements, Atmos. Environ., Part A, 27, 3037–3038, 1993. Knepp, T. N., Bottenheim, J., Carlsen, M., Carlson, D., Donohoue, D., Friederich, G., Matrai, P. A., Netcheva, S., Perovich, D. K., Santini, R., Shepson, P. B., Simpson, W., Valentic, T., Williams, C., and Wyss, P. J.: Development of an autonomous sea ice tethered buoy for the study of ocean-atmosphere-sea ice-snow pack interactions: the O-buoy, Atmos. Meas. Tech., 3, 249–261, <a href="http://dx.doi.org/10.5194/amt-3-249-2012">https://doi.org/10.5194/amt-3-249-2012</a>, 2010. Koo, J. H., Wang, Y., Kurosu, T. P., Chance, K., Rozanov, A., Richter, A., Oltmans, S. J., Thompson, A. M., Hair, J. W., Fenn, M. A., Weinheimer, A. J., Ryerson, T. B., Solberg, S., Huey, L. G., Liao, J., Dibb, J. E., Neuman, J. A., Nowak, J. B., Pierce, R. B., Natarajan, M., and Al-Saadi, J.: Characteristics of tropospheric ozone depletion events in the Arctic spring: analysis of the ARCTAS, ARCPAC, and ARCIONS measurements and satellite BrO observations, Atmos. Chem. Phys., 12, 9909–9922, <a href="http://dx.doi.org/10.5194/acp-12-9909-2012">https://doi.org/10.5194/acp-12-9909-2012</a>, 2012. Kwok, R., Cunningham, G. F., Wensnahan, M., Rigor, I., Zwally, H. J., and Yi, D.: Thinning and volume loss of the Arctic Ocean sea ice cover: 2003–2008, J. Geophys. Res., 114, C07005, <a href="http://dx.doi.org/10.1029/2009JC005312">https://doi.org/10.1029/2009JC005312</a>, 2009. Le Bras, G. and Platt, U.: A Possible Mechanism for Combined Chlorine and Bromine Catalyzed Destruction of Tropospheric Ozone in the Arctic, Geophys. Res. Lett., 22, 599–602, <a href="http://dx.doi.org/10.1029/94GL03334">https://doi.org/10.1029/94GL03334</a>, 1995. Leaitch, W. R., Barrie, L. A., Bottenheim, J. W., Li, S. M., Shepson, P. B., Muthuramu, K., and Yokouchi, Y.: Airborne Observations Related to Ozone Depletion at Polar Sunrise, J. Geophys. Res., 99, 25499–25517, 1994. Lehrer, E., Hönninger, G., and Platt, U.: A one dimensional model study of the mechanism of halogen liberation and vertical transport in the polar troposphere, Atmos. Chem. Phys., 4, 2427–2440, <a href="http://dx.doi.org/10.5194/acp-4-2427-2004">https://doi.org/10.5194/acp-4-2427-2004</a>, 2004. Liao, J., Huey, L. G., Tanner, D. J., Flocke, F. M., Orlando, J. J., Neuman, J. A., Nowak, J. B., Weinheimer, A. J., Hall, S. R., Smith, J. N., Fried, A., Staebler, R. M., Wang, Y., Koo, J. H., Cantrell, C. A., Weibring, P., Walega, J., Knapp, D. J., Shepson, P. B., and Stephens, C. R.: Observations of inorganic bromine (HOBr, BrO, and Br<sub>2</sub>) speciation at Barrow, Alaska, in spring 2009, J. Geophys. Res., 117, D00R16, <a href="http://dx.doi.org/10.1029/2011JD016641">https://doi.org/10.1029/2011JD016641</a>, 2012. Liao, J., Huey, L. G., Liu, Z., Tanner, D. J., Cantrell, C. A., Orlando, J. J., Flocke, F. M., Shepson, P. B., Weinheimer, A. J., Hall, S. R., Ullmann, K., Beine, H. J., Wang, Y., Ingall, E. D., Stephens, C. R., Hornbrook, R. S., Apel, E. C., Riemer, D., Fried, A., Mauldin III, R. L., Smith, J. N., Staebler, R. M., Neuman, J. A., and Nowak, J. B.: High levels of molecular chlorine in the Arctic atmosphere, Nature Geosci, 7, 91–94, <a href="http://dx.doi.org/10.1038/ngeo2046">https://doi.org/10.1038/ngeo2046</a>, 2014. 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, <a href="http://dx.doi.org/10.1029/2009JD013665">https://doi.org/10.1029/2009JD013665</a>, 2010. Martinez, M., Arnold, T., and Perner, D.: The role of bromine and chlorine chemistry for arctic ozone depletion events in Ny-Ålesund and comparison with model calculations, Ann. Geophys., 17, 941–956, <a href="http://dx.doi.org/10.1007/s00585-999-0941-4">https://doi.org/10.1007/s00585-999-0941-4</a>, 1999. Michalowski, B. A., Francisco, J. S., Li, S.-M., Barrie, L. A., Bottenheim, J. W., and Shepson, P. B.: A computer model study of multiphase chemistry in the Arctic boundary layer during polar sunrise, J. Geophys. Res., 105, 15131–15145, <a href="http://dx.doi.org/10.1029/2000JD900004">https://doi.org/10.1029/2000JD900004</a>, 2000. 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° N, 51° W), Tellus B, 49, 496–509, <a href="http://dx.doi.org/10.1034/j.1600-0889.49.issue5.6.x">https://doi.org/10.1034/j.1600-0889.49.issue5.6.x</a>, 1997. Moore, C. W., Obrist, D., Steffen, A., Staebler, R. M., Douglas, T. A., Richter, A., and Nghiem, S. V.: Convective forcing of mercury and ozone in the Arctic boundary layer induced by leads in sea ice, Nature, 506, 81–84, <a href="http://dx.doi.org/10.1038/nature12924">https://doi.org/10.1038/nature12924</a>, 2014. Morin, S., Hönninger, G. H., Staebler, R. M., and Bottenheim, J. W.: A high time resolution study of boundary layer ozone chemistry and dynamics over the Arctic Ocean near Alert, Nunavut, Geophys. Res. Lett., 32, L08809, <a href="http://dx.doi.org/10.1029/2004GL022098">https://doi.org/10.1029/2004GL022098</a>, 2005. Neuman, J. A., Nowak, J. B., Huey, L. G., Burkholder, J. B., Dibb, J. E., Holloway, J. S., Liao, J., Peischl, J., Roberts, J. M., Ryerson, T. B., Scheuer, E., Stark, H., Stickel, R. E., Tanner, D. J., and Weinheimer, A.: Bromine measurements in ozone depleted air over the Arctic Ocean, Atmos. Chem. Phys., 10, 6503–6514, <a href="http://dx.doi.org/10.5194/acp-10-6503-2010">https://doi.org/10.5194/acp-10-6503-2010</a>, 2010. Nghiem, S. V., Rigor, I. G., Richter, A., Burrows, J. P., Shepson, P. B., Bottenheim, J., Barber, D. G., Steffen, A., Latonas, J., Wang, F. Y., Stern, G., Clemente-Colon, P., Martin, S., Hall, D. K., Kaleschke, L., Tackett, P., Neumann, G., and Asplin, M. G.: Field and satellite observations of the formation and distribution of Arctic atmospheric bromine above a rejuvenated sea ice cover, J. Geophys. Res., 117, D00S05, <a href="http://dx.doi.org/10.1029/2011JD016268">https://doi.org/10.1029/2011JD016268</a>, 2012. Oltmans, S. J., Johnson, B. J., and Harris, J. M.: Springtime boundary layer ozone depletion at Barrow, Alaska: Meteorological influence, year-to-year variation, and long-term change, J. Geophys. Res., 117, D00R18, <a href="http://dx.doi.org/10.1029/2011JD016889">https://doi.org/10.1029/2011JD016889</a>, 2012. Piot, M. and von Glasow, R.: The potential importance of frost flowers, recycling on snow, and open leads for ozone depletion events, Atmos. Chem. Phys., 8, 2437–2467, <a href="http://dx.doi.org/10.5194/acp-8-2437-2008">https://doi.org/10.5194/acp-8-2437-2008</a>, 2008. Piot, M. and von Glasow, R.: Modelling the multiphase near-surface chemistry related to ozone depletions in polar spring, J. Atmos. Chem., 64, 77–105, <a href="http://dx.doi.org/10.1007/s10874-010-9170-1">https://doi.org/10.1007/s10874-010-9170-1</a>, 2009. Pöhler, D., Vogel, L., Frieß, U., and Platt, U.: Observation of halogen species in the Amundsen Gulf, Arctic, by active long-path differential optical absorption spectroscopy, Prog. Natl. Acad. Sci., 107, 6582–6587, <a href="http://dx.doi.org/10.1073/pnas.0912231107">https://doi.org/10.1073/pnas.0912231107</a>, 2010. Pratt, K. A., Custard, K. D., Shepson, P. B., Douglas, T. A., Pöhler, D., General, S., Zielcke, J., Simpson, W. R., Platt, U., Tanner, D. J., Huey, G. L., Carlsen, M., and Stirm, B. H.: Photochemical production of molecular bromine in Arctic surface snowpacks, Nature Geosci., 6, 351–356, <a href="http://dx.doi.org/10.1038/ngeo1779">https://doi.org/10.1038/ngeo1779</a>, 2013. 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. Ridley, B. A., Atlas, E. L., Montzka, D. D., Browell, E. V., Cantrell, C. A., Blake, D. R., Blake, N. J., Cinquini, L., Coffey, M. T., Emmons, L. K., Cohen, R. C., DeYoung, R. J., Dibb, J. E., Eisele, F. L., Flocke, F. M., Fried, A., Grahek, F. E., Grant, W. B., Hair, J. W., Hannigan, J. W., Heikes, B. J., Lefer, B. L., Mauldin, R. L., Moody, J. L., Shetter, R. E., Snow, J. A., Talbot, R. W., Thornton, J. A., Walega, J. G., Weinheimer, A. J., Wert, B. P., and Wimmers, A. J.: Ozone depletion events observed in the high latitude surface layer during the TOPSE aircraft program, J. Geophys. Res., 108, 8356, <a href="http://dx.doi.org/10.1029/2001JD001507">https://doi.org/10.1029/2001JD001507</a>, 2003. Rodgers, C. D.: Inverse Methods for Atmospheric Sounding: Theory and Practice, Series on Atmospheric, Oceanic, and Planetary Physics, edited by: Taylor, F. W., World Scientific Publishing, 46–50, 2000. 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, <a href="http://dx.doi.org/10.1126/Science.1141408">https://doi.org/10.1126/Science.1141408</a>, 2007. Salawitch, R. J., Canty, T., Kurosu, T., Chance, K., Liang, Q., da Silva, A., Pawson, S., Nielsen, J. E., Rodriguez, J. M., Bhartia, P. K., Liu, X., Huey, L. G., Liao, J., Stickel, R. E., Tanner, D. J., Dibb, J. E., Simpson, W. R., Donohoue, D., Weinheimer, A., Flocke, F., Knapp, D., Montzka, D., Neuman, J. A., Nowak, J. B., Ryerson, T. B., Oltmans, S., Blake, D. R., Atlas, E. L., Kinnison, D. E., Tilmes, S., Pan, L. L., Hendrick, F., Van Roozendael, M., Kreher, K., Johnston, P. V., Gao, R. S., Johnson, B., Bui, T. P., Chen, G., Pierce, R. B., Crawford, J. H., and Jacob, D. J.: A new interpretation of total column BrO during Arctic spring, Geophys. Res. Lett., 37, L21805, <a href="http://dx.doi.org/10.1029/2010GL043798">https://doi.org/10.1029/2010GL043798</a>, 2010. Schall, C. and Heumann, K. G.: GC determination of volatile organoiodine and organobromine compounds in Arctic seawater and air samples, Fresenius. J. Anal. Chem., 346, 717–722, <a href="http://dx.doi.org/10.1007/bf00321279">https://doi.org/10.1007/bf00321279</a>, 1993. Seabrook, J. A., Whiteway, J., Staebler, R. M., Bottenheim, J. W., Komguem, L., Gray, L. H., Barber, D., and Asplin, M.: LIDAR measurements of Arctic boundary layer ozone depletion events over the frozen Arctic Ocean, J. Geophys. Res., 116, D00S02, <a href="http://dx.doi.org/10.1029/2011JD016335">https://doi.org/10.1029/2011JD016335</a>, 2011. Seabrook, J. A., Whiteway, J. A., Gray, L. H., Staebler, R., and Herber, A.: Airborne lidar measurements of surface ozone depletion over Arctic sea ice, Atmos. Chem. Phys., 13, 6023–6029, <a href="http://dx.doi.org/10.5194/acp-13-6023-2013">https://doi.org/10.5194/acp-13-6023-2013</a>, 2013. Sheridan, P. J., Schnell, R. C., Zoller, W. H., Carlson, N. D., Rasmussen, R. A., Harris, J. M., and Sievering, H.: Composition of Br-Containing Aerosols and Cases Related to Boundary-Layer Ozone Destruction in the Arctic, Atmos. Environ., Part A, 27, 2839–2849, 1993. Simpson, W. R., Alvarez-Aviles, L., Douglas, T. A., Sturm, M., and Dominé, F.: Halogens in the coastal snow pack near Barrow, Alaska: Evidence for active bromine air-snow chemistry during springtime, Geophys. Res. Lett., 32, L04811, <a href="http://dx.doi.org/10.1029/2004GL021748">https://doi.org/10.1029/2004GL021748</a>, 2005. 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, <a href="http://dx.doi.org/10.5194/acp-7-621-2007">https://doi.org/10.5194/acp-7-621-2007</a>, 2007a. 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, <a href="http://dx.doi.org/10.5194/acp-7-4375-2007">https://doi.org/10.5194/acp-7-4375-2007</a>, 2007b. Solberg, S., Schmidbauer, N., Semb, A., Stordal, F., and Hov, O.: Boundary-layer ozone depletion as seen in the Norwegian Arctic in Spring, J. Atmos. Chem., 23, 301–332, <a href="http://dx.doi.org/10.1007/Bf00055158">https://doi.org/10.1007/Bf00055158</a>, 1996. Stephens, C. R.: Studies of tropospheric halogen radical chemistry during ozone and mercury depletion events in the Arctic, Ph.D., Chemistry, Purdue University, West Lafayette, IN, 356 pp., 2012. Strong, C., Fuentes, J. D., Davis, R. E., and Bottenheim, J. W.: Thermodynamic attributes of Arctic boundary layer ozone depletion, Atmos. Environ., 36, 2641–2652, 2002. Sumner, A. L., and Shepson, P. B.: Snowpack production of formaldehyde and its effect on the Arctic troposphere, Nature, 398, 230–233, 1999. Sumner, A. L., Shepson, P. B., Grannas, A. M., Bottenheim, J. W., Anlauf, K. G., Worthy, D., Schroeder, W. H., Steffen, A., Dominé, F., Perrier, S., and Houdier, S.: Atmospheric chemistry of formaldehyde in the Arctic troposphere at Polar Sunrise, and the influence of the snowpack, Atmos. Environ., 36, 2553–2562, <a href="http://dx.doi.org/10.1016/S1352-2310(02)00105-X">https://doi.org/10.1016/S1352-2310(02)00105-X</a>, 2002. Tang, T., and McConnell, J. C.: Autocatalytic release of bromine from Arctic snow pack during polar sunrise, Geophys. Res. Lett., 23, 2633–2636, <a href="http://dx.doi.org/10.1029/96GL02572">https://doi.org/10.1029/96GL02572</a>, 1996. Tarasick, D. W. and Bottenheim, J. W.: Surface ozone depletion episodes in the Arctic and Antarctic from historical ozonesonde records, Atmos. Chem. Phys., 2, 197-205, <a href="http://dx.doi.org/10.5194/acp-2-197-2002">https://doi.org/10.5194/acp-2-197-2002</a>, 2002. 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, <a href="http://dx.doi.org/10.5194/acp-11-1791-2011">https://doi.org/10.5194/acp-11-1791-2011</a>, 2011. Thompson, A. M.: The Oxidizing Capacity of the Earths Atmosphere - Probable Past and Future Changes, Science, 256, 1157–1165, 1992. Thompson, C. R., Shepson, P. B., Liao, J., Huey, L. G., and Cantrell, C.: Bromine atom production and chain propagation during springtime Arctic ozone depletion events in Barrow, Alaska, in preparation, 2014. Toyota, K., McConnell, J. C., Lupu, A., Neary, L., McLinden, C. A., Richter, A., Kwok, R., Semeniuk, K., Kaminski, J. W., Gong, S.-L., Jarosz, J., Chipperfield, M. P., and Sioris, C. E.: Analysis of reactive bromine production and ozone depletion in the Arctic boundary layer using 3-D simulations with GEM-AQ: inference from synoptic-scale patterns, Atmos. Chem. Phys., 11, 3949–3979, <a href="http://dx.doi.org/10.5194/acp-11-3949-2011">https://doi.org/10.5194/acp-11-3949-2011</a>, 2011. Tuckermann, M., Ackermann, R., Gölz, C., Lorenzen-Schmidt, H., Senne, T., Stutz, J., Trost, B., Unold, W., and Platt, U.: DOAS-observation of halogen radical-catalysed arctic boundary layer ozone destruction during the ARCTOC-campaigns 1995 and 1996 in Ny-Ålesund, Spitsbergen, Tellus B, 49, 533–555, 1997. Vogt, R., Crutzen, P. J., and Sander, R.: A mechanism for halogen release from sea-salt aerosol in the remote marine boundary layer, Nature, 383, 327-330, 1996. Wennberg, P.: Atmospheric chemistry – Bromine explosion, Nature, 397, 299–301, <a href="http://dx.doi.org/10.1038/16805">https://doi.org/10.1038/16805</a>, 1999. Yang, X., Pyle, J. A., and Cox, R. A.: Sea salt aerosol production and bromine release: Role of snow on sea ice, Geophys. Res. Lett., 35, L16815, <a href="http://dx.doi.org/10.1029/2008gl034536">https://doi.org/10.1029/2008gl034536</a>, 2008. Yang, X., Pyle, J. A., Cox, R. A., Theys, N., and Van Roozendael, M.: Snow-sourced bromine and its implications for polar tropospheric ozone, Atmos. Chem. Phys., 10, 7763–7773, <a href="http://dx.doi.org/10.5194/acp-10-7763-2010">https://doi.org/10.5194/acp-10-7763-2010</a>, 2010. Zeng, T., Wang, Y. H., Chance, K., Browell, E. V., Ridley, B. A., and Atlas, E. L.: Widespread persistent near-surface ozone depletion at northern high latitudes in spring, Geophys. Res. Lett., 30, 2298, <a href="http://dx.doi.org/10.1029/2003GL018587">https://doi.org/10.1029/2003GL018587</a>, 2003. Zhou, X. L., Beine, H. J., Honrath, R. E., Fuentes, J. D., Simpson, W., Shepson, P. B., and Bottenheim, J. W.: Snowpack photochemical production of HONO: a major source of OH in the Arctic boundary layer in springtime, Geophys. Res. Lett., 28, 4087–4090, <a href="http://dx.doi.org/10.1029/2001gl013531">https://doi.org/10.1029/2001gl013531</a>, 2001.