• Andrews, D. G., J. R. Holton, and C. B. Leovy, 1987: Middle Atmosphere Dynamics. International Geophysics Series, Vol. 40, Academic Press, 489 pp.

  • Bailey, S. M., and et al. , 2014: A multi tracer analysis of thermosphere to stratosphere descent triggered by the 2013 stratospheric sudden warming. Geophys. Res. Lett., 41, 52165222, https://doi.org/10.1002/2014GL059860.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Baldwin, M. P., and T. J. Dunkerton, 1999: Propagation of the Arctic Oscillation from the stratosphere to the troposphere. J. Geophys. Res., 104, 30 93730 946, https://doi.org/10.1029/1999JD900445.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Barriopedro, D., and N. Calvo, 2014: On the relationship between ENSO, stratospheric sudden warmings, and blocking. J. Climate, 27, 47044720, https://doi.org/10.1175/JCLI-D-13-00770.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Becker, E., 2009: Sensitivity of the upper mesosphere to the Lorenz energy cycle of the troposphere. J. Atmos. Sci., 66, 647666, https://doi.org/10.1175/2008JAS2735.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Butler, A. H., D. J. Seidel, S. C. Hardiman, N. Butchart, T. Birner, and A. Match, 2015: Defining sudden stratospheric warmings. Bull. Amer. Meteor. Soc., 96, 19131928, https://doi.org/10.1175/BAMS-D-13-00173.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chandran, A., R. L. Collins, and V. L. Harvey, 2014: Stratosphere–mesosphere coupling during stratospheric sudden warming events. Adv. Space Res., 53, 12651289, https://doi.org/10.1016/j.asr.2014.02.005.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Charlton, A. J., and L. M. Polvani, 2007: A new look at stratospheric sudden warmings: Part I: Climatology and modeling benchmarks. J. Climate, 20, 449469, https://doi.org/10.1175/JCLI3996.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Charlton-Perez, A. J., and L. M. Polvani, 2011: Corrigendum. J. Climate, 24, 5951, https://doi.org/10.1175/JCLI-D-11-00348.1.

  • Chau, J. L., B. G. Fejer, and L. P. Goncharenko, 2009: Quiet variability of equatorial E × B drifts during a sudden stratospheric warming event. Geophys. Res. Lett., 36, L05101, https://doi.org/10.1029/2008GL036785.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cohen, J., and J. Jones, 2011: Tropospheric precursors and stratospheric warmings. J. Climate, 24, 65626572, https://doi.org/10.1175/2011JCLI4160.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dee, D. P., and et al. , 2011: The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553597, https://doi.org/10.1002/qj.828.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • de la Torre, L., R. R. Garcia, D. Barriopedro, and A. Chandran, 2012: Climatology and characteristics of stratospheric sudden warmings in the Whole Atmosphere Community Climate Model. J. Geophys. Res., 117, D04110, https://doi.org/10.1029/2011JD016840.

    • Search Google Scholar
    • Export Citation
  • Dunkerton, T. J., and N. Butchard, 1984: Propagation and selective transmission of internal gravity waves in a sudden warming. J. Atmos. Sci., 41, 14431460, https://doi.org/10.1175/1520-0469(1984)041<1443:PASTOI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • ECMWF, 2016: IFS Documentation, Cy41r2: Operational implementation 8 March 2016. ECMWF, https://www.ecmwf.int/en/forecasts/documentation-and-support/changes-ecmwf-model/ifs-documentation.

  • Fuller-Rowell, T., F. Wu, R. A. Akmaev, T.-W. Fang, and E. Araujo-Pradere, 2010: A Whole Atmosphere Model simulation of the impact of a sudden stratospheric warming on the thermosphere dynamics and electrodynamics. J. Geophys. Res., 115, A00G08, https://doi.org/10.1029/2010JA015524.

    • Search Google Scholar
    • Export Citation
  • Funke, B., M. López-Puertas, D. Bermejo-Pantaleón, M. García-Comas, G. Stiller, T. von Clarmann, M. Kiefer, and A. Linden, 2010: Evidence for dynamical coupling from the lower atmosphere to the thermosphere during a major stratospheric warming event. Geophys. Res. Lett., 37, L13803, https://doi.org/10.1029/2010GL043619.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gerber, E. P., and et al. , 2010: Stratosphere–troposphere coupling and annular mode variability in chemistry–climate models. J. Geophys. Res., 115, D00M06, https://doi.org/10.1029/2009JD013770.

    • Search Google Scholar
    • Export Citation
  • Goncharenko, L. P., and S.-R. Zhang, 2008: Ionospheric signatures of sudden stratospheric warming: Ion temperature at middle latitude. Geophys. Res. Lett., 35, L21103, https://doi.org/10.1029/2008GL035684.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hines, C. O., 1997: Doppler-spread parameterization of gravity-wave momentum deposition in the middle atmosphere. Part 2: Broad and quasi-monochromatic spectra, and implementation. J. Atmos. Sol.-Terr. Phys., 59, 387400, https://doi.org/10.1016/S1364-6826(96)00080-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hitchcock, P., and T. G. Shepherd, 2013: Zonal-mean dynamics of extended recoveries from stratospheric sudden warmings. J. Atmos. Sci., 70, 688707, https://doi.org/10.1175/JAS-D-12-0111.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hitchcock, P., T. G. Shepherd, and G. L. Manney, 2013: Statistical characterization of arctic polar-night jet oscillation events. J. Climate, 26, 20962116, https://doi.org/10.1175/JCLI-D-12-00202.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Holton, J. R., 1982: The role of gravity wave induced drag and diffusion in the momentum budget of the mesosphere. J. Atmos. Sci., 39, 791799, https://doi.org/10.1175/1520-0469(1982)039<0791:TROGWI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Karlsson, B., C. McLandress, and T. G. Shepherd, 2009: Inter-hemispheric mesospheric coupling in a comprehensive middle atmosphere model. J. Atmos. Sol.-Terr. Phys., 71, 518530, https://doi.org/10.1016/j.jastp.2008.08.006.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kishore Kumar, G., and et al. , 2014: Mesosphere and lower thermosphere zonal wind over low latitudes: Relation to local stratospheric zonal winds and global circulation anomalies. J. Geophys. Res. Atmos., 119, 59135927, https://doi.org/10.1002/2014JD021610.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Körnich, H., G. Schmitz, and E. Becker, 2006: The role of stationary waves in the maintenance of the northern annular mode as deduced from model experiments. J. Atmos. Sci., 63, 29312947, https://doi.org/10.1175/JAS3799.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kuroda, Y., and K. Kodera, 2004: Role of the polar-night jet oscillation on the formation of the Arctic Oscillation in the Northern Hemisphere winter. J. Geophys. Res., 109, D11112, https://doi.org/10.1029/2003JD004123.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Labitzke, K., 1972: Temperature changes in the mesosphere and stratosphere connected with circulation changes in winter. J. Atmos. Sci., 29, 756766, https://doi.org/10.1175/1520-0469(1972)029<0756:TCITMA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lee, J. N., D. L. Wu, G. L. Manney, and M. J. Schwartz, 2009: Aura Microwave Limb Sounder observations of the northern annular mode: From the mesosphere to the upper troposphere. Geophys. Res. Lett., 36, L20807, https://doi.org/10.1029/2009GL040678.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Limpasuvan, V., J. H. Richter, Y. J. Orsolini, F. Stordal, and O.-K. Kvissel, 2012: The roles of planetary and gravity waves during a major stratospheric sudden warming as characterized by the WACCM. J. Atmos. Sol.-Terr. Phys., 78-79, 8498, https://doi.org/10.1016/j.jastp.2011.03.004.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, H.-L., and R. G. Roble, 2002: A study of a self-generated stratospheric sudden warming and its mesospheric–lower thermospheric impacts using the coupled TIME-GCM/CCM3. J. Geophys. Res., 107, 4695, doi:10.1029/2001JD001533.

    • Search Google Scholar
    • Export Citation
  • Liu, H.-L., and R. G. Roble, 2005: Dynamical coupling of the stratosphere and mesosphere in the 2002 Southern Hemisphere major stratospheric sudden warming. Geophys. Res. Lett., 32, L13804, https://doi.org/10.1029/2005GL022939.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Livesey, N. J., and et al. , 2015: Earth Observing System (EOS) Aura Microwave Limb Sounder (MLS) Version 4.2x Level 2 data quality and description document. Tech. Rep. JPL D-33509 Rev. B, Jet Propulsion Laboratory, California Institute of Technology, 169 pp., https://mls.jpl.nasa.gov/data/v4-2_data_quality_document.pdf.

  • Lott, F., and M. J. Miller, 1997: A new subgrid-scale orographic drag parameterization: Its foundation and testing. Quart. J. Roy. Meteor. Soc., 123, 101127, https://doi.org/10.1002/qj.49712353704.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Manney, G. L., and et al. , 2008: The evolution of the stratopause during the 2006 major warming: Satellite data and assimilated meteorological analyses. J. Geophys. Res., 113, D11115, https://doi.org/10.1029/2007JD009097.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Manney, G. L., and et al. , 2009: Aura Microwave Limb Sounder observations of dynamics and transport during the record-breaking 2009 Arctic stratospheric major warming. Geophys. Res. Lett., 36, L12815, https://doi.org/10.1029/2009GL038586.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Matsuno, T., 1971: A dynamical model of the stratospheric sudden warming. J. Atmos. Sci., 28, 14791494, https://doi.org/10.1175/1520-0469(1971)028<1479:ADMOTS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Matthewman, N., J. Esler, A. J. Charlton-Perez, and L. M. Polvani, 2009: A new look at sudden stratospheric warmings. Part III: Polar vortex evolution and vertical structure. J. Climate, 22, 15661585, https://doi.org/10.1175/2008JCLI2365.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McLandress, C., and T. G. Shepherd, 2009: Impact of climate change on stratospheric sudden warmings as simulated by the Canadian Middle Atmosphere Model. J. Climate, 22, 54495463, https://doi.org/10.1175/2009JCLI3069.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McLandress, C., J. F. Scinocca, T. G. Shepherd, M. C. Reader, and G. L. Manney, 2013: Dynamical control of the mesosphere by orographic and nonorographic gravity wave drag during the extended northern winters in 2006 and 2009. J. Atmos. Sci., 70, 21522169, https://doi.org/10.1175/JAS-D-12-0297.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Miller, A., H. Schmidt, and F. Bunzel, 2013: Vertical coupling of the middle atmosphere during stratospheric warming events. J. Atmos. Sol.-Terr. Phys., 97, 1121, https://doi.org/10.1016/j.jastp.2013.02.008.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mirzaei, M., C. Zülicke, A. R. Mohebalhojeh, F. Ahmadi-Givi, and R. Plougonven, 2014: Structure, energy, and parameterization of inertia–gravity waves in dry and moist simulations of a baroclinic wave life cycle. J. Atmos. Sci., 71, 23902414, https://doi.org/10.1175/JAS-D-13-075.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mitchell, D. M., A. J. Charlton-Perez, and L. J. Gray, 2011: Characterizing the variability and extremes of the stratospheric polar vortices using 2D moment analysis. J. Atmos. Sci., 68, 11941213, https://doi.org/10.1175/2010JAS3555.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mitchell, D. M., L. J. Gray, J. Anstey, M. P. Baldwin, and A. J. Charlton-Perez, 2013: The influence of stratospheric vortex displacements and splits on surface climate. J. Climate, 26, 26682682, https://doi.org/10.1175/JCLI-D-12-00030.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Orsolini, Y. J., J. Urban, D. P. Murtagh, S. Lossow, and V. Limpasuvan, 2010: Descent from the polar mesosphere and anomalously high stratopause observed in 8 years of water vapor and temperature satellite observations by the Odin sub-millimeter radiometer. J. Geophys. Res., 115, D12305, https://doi.org/10.1029/2009JD013501.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pedatella, N. M., H.-L. Liu, F. Sassi, J. Lei, J. L. Chau, and X. Zhang, 2014a: Ionospheric variability during the 2009 SSW: Influence of the lunar semidiurnal tide and mechanisms producing electron density variability. J. Geophys. Res. Space Physics, 119, 38283843, https://doi.org/10.1002/2014JA019849.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pedatella, N. M., and et al. , 2014b: The neutral dynamics during the 2009 sudden stratosphere warming simulated by different whole atmosphere models. J. Geophys. Res. Space Physics, 119, 13061324, https://doi.org/10.1002/2013JA019421.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pérot, K., J. Urban, and D. P. Murtagh, 2014: Unusually strong nitric oxide descent in the Arctic middle atmosphere in early 2013 as observed by Odin/SMR. Atmos. Chem. Phys., 14, 80098015, https://doi.org/10.5194/acp-14-8009-2014.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Quiroz, R. S., 1969: The warming of the upper stratosphere in February 1966 and the associated structure of the mesosphere. Mon. Wea. Rev., 97, 541552, https://doi.org/10.1175/1520-0493(1969)097<0541:TWOTUS>2.3.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Reichler, T., J. Kim, E. Manzini, and J. Kröger, 2012: A stratospheric connection to the Atlantic climate variability. Nat. Geosci., 5, 783787, https://doi.org/10.1038/ngeo1586.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ren, S., S. M. Polavarapu, S. R. Beagley, Y. Nezlin, and Y. J. Rochon, 2011: The impact of gravity wave drag on mesospheric analyses of the 2006 stratospheric major warming. J. Geophys. Res., 116, D19116, https://doi.org/10.1029/2011JD015943.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Richter, J. H., F. Sassi, and R. R. Garcia, 2010: Toward a physically based gravity wave source parameterization in a general circulation model. J. Atmos. Sci., 67, 136156, https://doi.org/10.1175/2009JAS3112.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Scherhag, R., 1952: Die explosionsartigen Stratosphärenerwärmungen des Spätwinters 1951/52. Ber. Dtsch. Wetterdienstes US-Zone, 6 (38), 5163.

    • Search Google Scholar
    • Export Citation
  • Schmidt, H., and et al. , 2006: The HAMMONIA chemistry climate model: Sensitivity of the mesopause region to the 11-year solar cycle and CO2 doubling. J. Climate, 19, 39033931, https://doi.org/10.1175/JCLI3829.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schoeberl, M. R., 1978: Stratospheric warmings: Observations and theory. Rev. Geophys. Space Phys., 16, 521538, https://doi.org/10.1029/RG016i004p00521.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Seviour, W. J., D. M. Mitchell, and L. J. Gray, 2013: A practical method to identify displaced and split stratospheric polar vortex events. Geophys. Res. Lett., 40, 52685273, https://doi.org/10.1002/grl.50927.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shepherd, M., S. R. Beagley, and V. I. Fomichev, 2014: Stratospheric warming influence on the mesosphere/lower thermosphere as seen by the extended CMAM. Ann. Geophys., 32, 589608, https://doi.org/10.5194/angeo-32-589-2014.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sigmond, M., J. F. Scinocca, V. Kharin, and T. G. Shepherd, 2013: Enhanced seasonal forecast skill following stratospheric sudden warmings. Nat. Geosci., 6, 98102, https://doi.org/10.1038/ngeo1698.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Siskind, D. E., S. D. Eckermann, J. P. McCormack, L. Coy, K. W. Hoppel, and N. L. Baker, 2010: Case studies of the mesospheric response to recent minor, major and extended stratospheric warmings. J. Geophys. Res., 114, D00N03, doi:10.1029/2010JD014114.

    • Search Google Scholar
    • Export Citation
  • Tan, B., X. Chu, H.-L. Liu, C. Yamashita, and J. M. Russell, 2012: Zonal-mean global teleconnection from 15 to 110 km derived from SABER and WACCM. J. Geophys. Res., 117, D10106, https://doi.org/10.1029/2011JD016750.

    • Search Google Scholar
    • Export Citation
  • Tomikawa, Y., 2010: Persistence of easterly wind during major stratospheric sudden warmings. J. Climate, 23, 52585267, https://doi.org/10.1175/2010JCLI3507.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tomikawa, Y., K. Sato, S. Watanabe, Y. Kawatani, K. Miyazaki, and M. Takahashi, 2012: Growth of planetary waves and the formation of an elevated stratopause after a major stratospheric sudden warming in a T213L256 GCM. J. Geophys. Res., 117, D16101, https://doi.org/10.1029/2011JD017243.

    • Search Google Scholar
    • Export Citation
  • Vignon, E., and D. M. Mitchell, 2015: The stratopause evolution during different types of sudden stratospheric warming event. Climate Dyn., 44, 33233337, https://doi.org/10.1007/s00382-014-2292-4.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • von Storch, H., and F. W. Zwiers, 2003: Statistical Analysis in Climate Research. Cambridge University Press, 484 pp.

  • Watanabe, S., Y. Kawatani, Y. Tomikawa, K. Miyazaki, M. Takahashi, and K. Sato, 2008: General aspects of a T213L256 middle atmosphere general circulation model. J. Geophys. Res., 113, D12110, doi:10.1029/2008JD010026.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xu, X., A. H. Manson, C. E. Meek, T. Chshylkova, J. Drummond, C. Hall, D. Riggin, and R. Hibbins, 2009: Vertical and interhemispheric links in the stratosphere–mesosphere as revealed by the day-to-day variability of Aura-MLS temperature data. Ann. Geophys., 27, 33873409, https://doi.org/10.5194/angeo-27-3387-2009.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zülicke, C., and D. H. W. Peters, 2008: Parameterization of strong stratospheric inertia–gravity waves forced by poleward-breaking Rossby waves. Mon. Wea. Rev., 136, 98119, https://doi.org/10.1175/2007MWR2060.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zülicke, C., and D. H. W. Peters, 2010: On the estimation of persistence in geophysical time series. Eur. Phys. J. Spec. Top., 187, 101108, https://doi.org/10.1140/epjst/e2010-01275-2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zülicke, C., and E. Becker, 2013: The structure of the mesosphere during sudden stratospheric warmings in a global circulation model. J. Geophys. Res. Atmos., 118, 22552271, doi:10.1002/jgrd.50219.

    • Crossref
    • Search Google Scholar
    • Export Citation
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Coupling of Stratospheric Warmings with Mesospheric Coolings in Observations and Simulations

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  • 1 Leibniz Institute of Atmospheric Physics, Kühlungsborn, Germany
  • | 2 Max Planck Institute of Meteorology, Hamburg, Germany
  • | 3 High Altitude Observatory, National Center of Atmospheric Research, Boulder, Colorado
  • | 4 Environmental Physics Laboratory, University of Vigo, Ourense, Spain
  • | 5 Department of Physics, University of Oxford, Oxford, and School of Geographical Science, University of Bristol, Bristol, United Kingdom
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Abstract

The vertical coupling between the stratosphere and the mesosphere is diagnosed from polar cap temperatures averaged over 60°–90°N with a new method: the joint occurrence of a warm stratosphere at 10 hPa and a cold mesosphere at 0.01 hPa. The investigation of an 11-yr-long dataset (2004–15) from Aura-MLS observations shows that such mesospheric coupling days appear in 7% of the winter. During major sudden stratospheric warming events mesospheric couplings are present with an enhanced average daily frequency of 22%. This daily frequency changes from event to event but broadly results in five of seven major warmings being classified as mesospheric couplings (2006, 2008, 2009, 2010, and 2013). The observed fraction of mesospheric coupling events (71%) is compared with simulations of the Kühlungsborn Mechanistic Circulation Model (KMCM), the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), and the Whole Atmosphere Community Climate Model (WACCM). The simulated fraction of mesospheric coupling events ranges between 57% and 94%, which fits the observations. In searching for causal relations weak evidence is found that major warming events with strong intensity or split vortices favor their coupling with the upper mesosphere. More evidence is found with a conceptual model: an effective vertical coupling between 10 and 0.01 hPa is provided by deep zonal-mean easterlies at 60°N, which are acting as a gravity-wave guide. The explained variance is above 40% in the four datasets, which indicates a near-realistic simulation of this process.

© 2018 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Christoph Zülicke, zuelicke@iap-kborn.de

This article is included in the Multi-Scale Dynamics of Gravity Waves (MS-GWaves) Special Collection.

Abstract

The vertical coupling between the stratosphere and the mesosphere is diagnosed from polar cap temperatures averaged over 60°–90°N with a new method: the joint occurrence of a warm stratosphere at 10 hPa and a cold mesosphere at 0.01 hPa. The investigation of an 11-yr-long dataset (2004–15) from Aura-MLS observations shows that such mesospheric coupling days appear in 7% of the winter. During major sudden stratospheric warming events mesospheric couplings are present with an enhanced average daily frequency of 22%. This daily frequency changes from event to event but broadly results in five of seven major warmings being classified as mesospheric couplings (2006, 2008, 2009, 2010, and 2013). The observed fraction of mesospheric coupling events (71%) is compared with simulations of the Kühlungsborn Mechanistic Circulation Model (KMCM), the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), and the Whole Atmosphere Community Climate Model (WACCM). The simulated fraction of mesospheric coupling events ranges between 57% and 94%, which fits the observations. In searching for causal relations weak evidence is found that major warming events with strong intensity or split vortices favor their coupling with the upper mesosphere. More evidence is found with a conceptual model: an effective vertical coupling between 10 and 0.01 hPa is provided by deep zonal-mean easterlies at 60°N, which are acting as a gravity-wave guide. The explained variance is above 40% in the four datasets, which indicates a near-realistic simulation of this process.

© 2018 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Christoph Zülicke, zuelicke@iap-kborn.de

This article is included in the Multi-Scale Dynamics of Gravity Waves (MS-GWaves) Special Collection.

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