ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-10-17491-2010 Attribution of stratospheric ozone trends to chemistry and transport: a modelling study Kiesewetter G. 1 Sinnhuber B.-M. 1 Weber M. 1 Burrows J. P. 1 Institute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany 20 07 2010 10 7 17491 17525 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-discuss.net/10/17491/2010/acpd-10-17491-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/10/17491/2010/acpd-10-17491-2010.pdf

The decrease of the concentration of ozone depleting substances (ODS) in the stratosphere over the past decade raises the question to what extent observed changes in stratospheric ozone over this period are consistent with known changes in chemical composition and possible changes in atmospheric transport. Here we present a series of ozone sensitivity calculations with a stratospheric chemistry transport model (CTM) driven with meteorological reanalyses from the European Centre for Medium Range Weather Forecast, covering the period 1978–2009. In order to account for the reversal in ODS trends, ozone trends are analysed in two periods, 1979–1999 and 2000–2009. Effects of ODS changes on the ozone chemistry are either accounted for or left out, allowing for a distinct attribution of ozone trends to the different factors of variability, namely ODS acting via gas phase chemistry, ODS acting via polar heterogeneous chemistry, and changes in transport and temperature. Modeled column ozone trends are in excellent agreement with observed trends from the Total Ozone Mapping Spectrometer (TOMS) and Solar Backscatter UV (SBUV/2) as well as the Global Ozone Monitoring Experiment (GOME/GOME2) and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instruments. For the 1979–1999 period we find that changes in ODS are the dominant source of the ozone trend, while changes in transport also contribute signifcantly to the overall trend. In contrast, for the period 2000–2009 the effect of ODS changes on total ozone is small. Observed ozone changes can be reproduced well with the CTM driven with meteorological reanalyses, indicating that the observed evolution of ozone over the past decade is consistent with our current understanding of chemistry and transport.

 References Bovensmann,~H., Burrows,~J P., Buchwitz,~M., Frerick,~J., Noel,~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. Bracher,~A., Lamsal,~L N., Weber,~M., Bramstedt,~K., Coldewey-Egbers,~M., and Burrows,~J P.: Global satellite validation of SCIAMACHY \chemO_3 columns with GOME WFDOAS, Atmos. Chem. Phys., 5, 2357–2368, \doi10.5194/acp-5-2357-2005, 2005. %%ok Braesicke,~P. and Pyle,~J A.: Changing ozone and changing circulation in northern mid-latitudes: possible feedbacks?, Geophys. Res. Lett., 30, 1059, \doi10.1029/2002GL015973, 2003. Callies,~J., Corpaccioli,~E., Eisinger,~M., Hahne,~A., and Lefebvre,~A.: GOME-2 – METOP's second-generation sensor for operational ozone monitoring, ESA Bull.-Eur. Space, 102, 28–36, 2000. Chipperfield,~M P.: A three-dimensional model study of long-term mid-high latitude lower stratosphere ozone changes, Atmos. Chem. Phys., 3, 1253–1265, \doi10.5194/acp-3-1253-2003, 2003. %%%ok Coldewey-Egbers,~M., Weber,~M., Lamsal,~L N., de Beek,~R., Buchwitz,~M., and Burrows,~J P.: Total ozone retrieval from GOME UV spectral data using the weighting function DOAS approach, Atmos. Chem. Phys., 5, 1015–1025, \doi10.5194/acp-5-1015-2005, 2005. %%ok Dhomse,~S., Weber,~M., Wohltmann,~I., Rex,~M., and Burrows,~J P.: On the possible causes of recent increases in northern hemispheric total ozone from a statistical analysis of satellite data from 1979 to 2003, Atmos. Chem. Phys., 6, 1165–1180, \doi10.5194/acp-6-1165-2006, 2006. %%ok Feng,~W., Chipperfield,~M P., Dorf,~M., Pfeilsticker,~K., and Ricaud,~P.: Mid-latitude ozone changes: studies with a 3-D CTM forced by ERA-40 analyses, Atmos. Chem. Phys., 7, 2357–2369, \doi10.5194/acp-7-2357-2007, 2007. %%ok Fortuin,~J F P. and Kelder,~H.: An ozone climatology based on ozonesondes and satellite measurements, J. Geophys. Res., 103, 31709–31734, 1998. Hadjinicolaou,~P., Jrrar,~A., Pyle,~J A., and Bishop,~L.: The dynamically driven long-term trend in stratospheric ozone over northern middle latitudes, Q. J. Roy. Meteor. Soc., 128, 1393–1412, 2002. Hadjinicolaou,~P., Pyle,~J A., and Harris,~N R P.: The recent turnaround in stratospheric ozone over northern middle latitudes: a~dynamical modeling perspective, Geophys. Res. Lett., 32, 12821, \doi10.1029/2005GL022476, 2005. Harris, N. R. P., Hudson,~R., and Phillips,~C. (Eds.): Assessment of trends in the vertical distribution of ozone. SPARC Rep. 1, WMO-Ozone Research and Monitoring Project Rep. 43, 1998. Harris,~N R P., Kyrö,~E., Staehelin,~J., Brunner,~D., Andersen,~S.-B., Godin-Beekmann,~S., Dhomse,~S., Hadjinicolaou,~P., Hansen,~G., Isaksen,~I., Jrrar,~A., Karpetchko,~A., Kivi,~R., Knudsen,~B., Krizan,~P., Lastovicka,~J., Maeder,~J., Orsolini,~Y., Pyle,~J A., Rex,~M., Vanicek,~K., Weber,~M., Wohltmann,~I., Zanis,~P., and Zerefos,~C.: Ozone trends at northern mid- and high latitudes – a European perspective, Ann. Geophys., 26, 1207–1220, \doi10.5194/angeo-26-1207-2008, 2008. %%ok Hood,~L L., McCormack,~J P., and Labitzke,~K.: An investigation of dynamical contributions to midlatitude ozone trends in winter, J. Geophys. Res., 102, 13079–13093, 1997. Hsu,~J. and Prather,~M J.: Stratospheric variability and tropospheric ozone, J. Geophys. Res., 114, D06102, \doi10.1029/2008JD010942, 2009. Jones,~A E. and Shanklin,~J D.: Continued decline of total ozone over Halley, Antarctica, since 1985, Nature, 376, 409–411, 1995. Kiesewetter,~G., Sinnhuber,~B.-M., Vountas,~M., Weber,~M., and Burrows,~J P.: A~long-term stratospheric ozone dataset from assimilation of satellite observations: high-latitude ozone anomalies, J. Geophys. Res., 115, D10307, \doi10.1029/2009JD013362, 2010. McLinden,~C A., Olsen,~S C., Hannegan,~B., Wild,~O., Prather,~M J., and Sundet,~J.: Stratospheric ozone in 3-D models: a~simple chemistry and the cross-tropopause flux, J. Geophys. Res., 105, 14653–14665, 2000. Newman,~P A., Nash,~E R., Kawa,~S R., Montzka,~S A., and Schauffler,~S M.: When will the Antarctic ozone hole recover?, Geophys. Res. Lett., 33, L12814, \doi10.1029/2005GL025232, 2006. Randel,~W. J. and Wu,~F.: Cooling of the arctic and antarctic polar stratospheres due to ozone depletion, J. Climate, 12, 1467–1469, 1999. Randel,~W J., Wu,~F., and Stolarski,~R.: Changes in column ozone correlated with the stratospheric EP flux, J. Meteorol. Soc. Jpn., 80, 849–862, 2002. Shine,~K P.: The middle atmosphere in the absence of dynamical heat fluxes, Q. J. Roy. Meteor. Soc., 113, 603–633, 1987. Shine,~K P., Bourqui,~M S., de~F Forster,~P M., Hare,~S H E., Langematz,~U., Braesicke,~P., Grewe,~V., Ponater,~M., Schnadt,~C., Smith,~C A., Haigh,~J D., Austin,~J., Butchart,~N., Shindell,~D T., Randel,~W J., Nagashima,~T., Portmann,~R W., Solomon,~S., Seidel,~D J., Lanzante,~J., Klein,~S., Ramaswamy,~V., and Schwarzkopf,~M D.: A~comparison of model-simulated trends in stratospheric temperatures, Q. J. Roy. Meteor. Soc., 129, 1565–1588, \doi10.1256/qj.02.186, 2003. Sinnhuber,~B.-M., Weber,~M., Amankwah,~A., and Burrows,~J P.: Total ozone during the unusual Antarctic winter of 2002, Geophys. Res. Lett., 30, 1580, \doi10.1029/2002GL016798, 2003. Sinnhuber, B.-M., Sheode, N., Sinnhuber, M., Chipperfield, M. P., and Feng, W.: The contribution of anthropogenic bromine emissions to past stratospheric ozone trends: a modelling study, Atmos. Chem. Phys., 9, 2863–2871, doi:10.5194/acp-9-2863-2009, 2009. Solomon,~S., Portmann,~R W., Garcia,~R., Thomason,~L W., Poole,~L R., and McCormick,~M.: The role of aerosol variations in anthropogenic ozone depletion at northern midlatitudes, J. Geophys. Res., 101, 6713–6727, 1996. Solomon,~S., Portmann,~R W., Garcia,~R R., Randel,~W., Wu,~F., Nagatani,~R., Gleason,~J., Thomason,~L., Poole,~L R., and Mc-Cormick,~M P.: Ozone depletion at mid-latitudes: coupling of volcanic aerosols and temperature variability to anthropogenic chlorine, Geophys. Res. Lett., 28, 1871–1874, 1998. Stolarski,~R S. and Frith,~S M.: Search for evidence of trend slow-down in the long-term TOMS/SBUV total ozone data record: the importance of instrument drift uncertainty, Atmos. Chem. Phys., 6, 4057–4065, \doi10.5194/acp-6-4057-2006, 2006. %%%ok Stolarski,~R S., Douglass,~A R., Steenrood,~S., and Pawson,~S.: Trends in stratospheric ozone: lessons learned from a~3-D chemical transport model, J. Atmos. Sci., 63, 1028–1041, 2006. Weber,~M., Lamsal,~L N., Coldewey-Egbers,~M., Bramstedt,~K., and Burrows,~J P.: Pole-to-pole validation of GOME WFDOAS total ozone with groundbased data, Atmos. Chem. Phys., 5, 1341–1355, \doi10.5194/acp-5-1341-2005, 2005. %%%ok Weber,~M., Lamsal,~L N., and Burrows,~J P.: Improved SCIAMACHY WFDOAS total ozone retrieval: Steps towards homogenising long-term total ozone datasets from GOME, SCIAMACHY, and GOME2, in: Proc. \qutEnvisat Symposium 2007, Montreux, Switzerland, 23–27 April 2007, ESA SP-636, 2007. Wohltmann,~I., Lehmann,~R., Rex,~M., Brunner,~D., and Mader,~J.: A~process-oriented regression model for column ozone, J. Geophys. Res., 112, D12304, \doi10.1029/2006JD007573, 2007. World Meteorological Organization: Scientific Assessment of of Ozone Depletion: 2006, Global Ozone Research and Monitoring Project – Report No. 50, 2007.