• Baldwin, M. P., and T. J. Dunkerton, 1999: Downward propagation of the Arctic Oscillation from the stratosphere to the troposphere. J. Geophys. Res., 104 , 3093730946.

    • Search Google Scholar
    • Export Citation
  • Baldwin, M. P., and T. J. Dunkerton, 2001: Stratospheric harbingers of anomalous weather regimes. Science, 294 , 581584.

  • Baldwin, M. P., and D. W. J. Thompson, 2009: A critical comparison of stratosphere–troposphere coupling indices. Quart. J. Roy. Meteor. Soc., 135 , 16611672.

    • Search Google Scholar
    • Export Citation
  • Baldwin, M. P., D. B. Stevenson, D. D. W. Thompson, T. J. Dunkerton, A. J. Charlton, and A. O’Neill, 2003: Stratospheric memory and skill of extended-range weather forecasts. Science, 301 , 636640.

    • Search Google Scholar
    • Export Citation
  • Charney, J. G., and P. G. Drazin, 1961: Propagation of planetary disturbances from the lower into the upper atmosphere. J. Geophys. Res., 66 , 83109.

    • Search Google Scholar
    • Export Citation
  • Christiansen, B., 2001: Downward propagation of zonal mean zonal wind anomalies from the stratosphere to the troposphere: Model and reanalysis. J. Geophys. Res., 106 , 2730727322.

    • Search Google Scholar
    • Export Citation
  • Christiansen, B., 2003: Evidence for nonlinear climate change: Two stratospheric regimes and a regime shift. J. Climate, 16 , 36813689.

    • Search Google Scholar
    • Export Citation
  • Gerber, E. P., L. Polvani, and D. Ancukiewicz, 2008: Annular mode time scales in the Intergovernmental Panel on Climate Change Fourth Assessment Report models. Geophys. Res. Lett., 35 , L22707. doi:10.1029/2008GL035712.

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

    • Search Google Scholar
    • Export Citation
  • Gillett, N. P., and D. W. J. Thompson, 2003: Simulation of recent Southern Hemisphere climate change. Science, 302 , 273275.

  • Harnik, N., 2009: Observed stratospheric downward reflection and its relation to upward pulses of wave activity. J. Geophys. Res., 114 , D08120. doi:10.1029/2008JD010493.

    • Search Google Scholar
    • Export Citation
  • Harnik, N., and R. S. Lindzen, 2001: The effect of reflecting surfaces on the vertical structure and variability of stratospheric planetary waves. J. Atmos. Sci., 58 , 28722894.

    • Search Google Scholar
    • Export Citation
  • Karpetchko, A., E. Kyrö, and B. M. Knudsen, 2005: Arctic and Antarctic polar vortices 1957–2002 as seen from the ERA-40 reanalyses. J. Geophys. Res., 110 , D21109. doi:10.1029/2005JD006113.

    • Search Google Scholar
    • Export Citation
  • Lin, P., Q. Fu, S. Solomon, and J. M. Wallace, 2009: Temperature trend patterns in the Southern Hemisphere high latitudes: Novel indicators of stratospheric change. J. Climate, 22 , 63256341.

    • Search Google Scholar
    • Export Citation
  • Neff, W., 1999: Decadal time scale trends and variability in the tropospheric circulation over the South Pole. J. Geophys. Res., 104 , 2721727251.

    • Search Google Scholar
    • Export Citation
  • Neff, W., J. Perlwitz, and M. Hoerling, 2008: Observational evidence for asymmetric changes in tropospheric heights over Antarctica on decadal time scales. Geophys. Res. Lett., 35 , L18703. doi:10.1029/2008GL035074.

    • Search Google Scholar
    • Export Citation
  • Perlwitz, J., and N. Harnik, 2003: Observational evidence of a stratospheric influence on the troposphere by planetary wave reflection. J. Climate, 16 , 30113026.

    • Search Google Scholar
    • Export Citation
  • Perlwitz, J., and N. Harnik, 2004: Downward coupling between the stratosphere and troposphere: The relative roles of wave and zonal mean processes. J. Climate, 17 , 49024909.

    • Search Google Scholar
    • Export Citation
  • Perlwitz, J., S. Pawson, R. Fogt, J. E. Nielsen, and W. Neff, 2008: The impact of stratospheric ozone hole recovery on Antarctic climate. Geophys. Res. Lett., 35 , L08714. doi:10.1029/2008GL033317.

    • Search Google Scholar
    • Export Citation
  • Randel, W. J., 1987: A study of planetary waves in the southern winter troposphere and stratosphere. Part I: Wave structure and vertical propagation. J. Atmos. Sci., 44 , 917935.

    • Search Google Scholar
    • Export Citation
  • Randel, W. J., D. E. Stevens, and J. L. Stanford, 1987: A study of planetary waves in the southern winter troposphere and stratosphere. Part II: Life cycles. J. Atmos. Sci., 44 , 936949.

    • Search Google Scholar
    • Export Citation
  • Shaw, T. A., and T. G. Shepherd, 2008: Raising the roof. Nat. Geosci., 1 , 1213.

  • Thompson, D. W. J., and S. Solomon, 2002: Interpretation of recent Southern Hemisphere climate change. Science, 296 , 895899.

  • Thompson, D. W. J., M. Baldwin, and S. Solomon, 2005: Stratosphere–troposphere coupling in the southern hemisphere. J. Climate, 62 , 708715.

    • Search Google Scholar
    • Export Citation
  • Uppala, S. M., and Coauthors, 2005: The ERA-40 Re-Analysis. Quart. J. Roy. Meteor. Soc., 131 , 29613012.

  • Waugh, D. W., W. J. Randel, S. Pawson, P. A. Newman, and E. R. Nash, 1999: Persistence of the lower-stratospheric polar vortices. J. Geophys. Res., 104 , 2719127201.

    • Search Google Scholar
    • Export Citation
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Downward Wave Coupling between the Stratosphere and Troposphere: The Importance of Meridional Wave Guiding and Comparison with Zonal-Mean Coupling

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  • 1 Center for Atmosphere Ocean Science, Courant Institute of Mathematical Sciences, New York University, New York, New York
  • | 2 Cooperative Institute for Research in Environmental Sciences, University of Colorado, and NOAA/Earth System Research Laboratory/Physical Sciences Division, Boulder, Colorado
  • | 3 Department of Geophysics and Planetary Sciences, Tel Aviv University, Tel Aviv, Israel
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Abstract

The nature of downward wave coupling between the stratosphere and troposphere in both hemispheres is analyzed using the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) dataset. Downward wave coupling occurs when planetary waves reflected in the stratosphere impact the troposphere, and it is distinct from zonal-mean coupling, which results from wave dissipation and its subsequent impact on the zonal-mean flow. Cross-spectral correlation analysis and wave geometry diagnostics reveal that downward wave-1 coupling occurs in the presence of both a vertical reflecting surface in the mid-to-upper stratosphere and a high-latitude meridional waveguide in the lower stratosphere. In the Southern Hemisphere, downward wave coupling occurs from September to December, whereas in the Northern Hemisphere it occurs from January to March. A vertical reflecting surface is also present in the stratosphere during early winter in both hemispheres; however, it forms at the poleward edge of the meridional waveguide, which is not confined to high latitudes. The absence of a high-latitude waveguide allows meridional wave propagation into the subtropics and decreases the likelihood of downward wave coupling. The results highlight the importance of distinguishing between wave reflection in general, which requires a vertical reflecting surface, and downward wave coupling between the stratosphere and troposphere, which requires both a vertical reflecting surface and a high-latitude meridional waveguide.

The relative roles of downward wave and zonal-mean coupling in the Southern and Northern Hemispheres are subsequently compared. In the Southern Hemisphere, downward wave-1 coupling dominates, whereas in the Northern Hemisphere downward wave-1 coupling and zonal-mean coupling are found to be equally important from winter to early spring. The results suggest that an accurate representation of the seasonal cycle of the wave geometry is necessary for the proper representation of downward wave coupling between the stratosphere and troposphere.

* Current affiliation: Lamont-Doherty Earth Observatory and Department of Applied Physics and Applied Mathematics, Columbia University, Palisades, New York

Corresponding author address: Dr. Tiffany A. Shaw, Center for Atmosphere Ocean Science, Courant Institute of Mathematical Sciences, New York University, 251 Mercer St., New York, NY 10012. Email: tshaw@cims.nyu.edu

Abstract

The nature of downward wave coupling between the stratosphere and troposphere in both hemispheres is analyzed using the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) dataset. Downward wave coupling occurs when planetary waves reflected in the stratosphere impact the troposphere, and it is distinct from zonal-mean coupling, which results from wave dissipation and its subsequent impact on the zonal-mean flow. Cross-spectral correlation analysis and wave geometry diagnostics reveal that downward wave-1 coupling occurs in the presence of both a vertical reflecting surface in the mid-to-upper stratosphere and a high-latitude meridional waveguide in the lower stratosphere. In the Southern Hemisphere, downward wave coupling occurs from September to December, whereas in the Northern Hemisphere it occurs from January to March. A vertical reflecting surface is also present in the stratosphere during early winter in both hemispheres; however, it forms at the poleward edge of the meridional waveguide, which is not confined to high latitudes. The absence of a high-latitude waveguide allows meridional wave propagation into the subtropics and decreases the likelihood of downward wave coupling. The results highlight the importance of distinguishing between wave reflection in general, which requires a vertical reflecting surface, and downward wave coupling between the stratosphere and troposphere, which requires both a vertical reflecting surface and a high-latitude meridional waveguide.

The relative roles of downward wave and zonal-mean coupling in the Southern and Northern Hemispheres are subsequently compared. In the Southern Hemisphere, downward wave-1 coupling dominates, whereas in the Northern Hemisphere downward wave-1 coupling and zonal-mean coupling are found to be equally important from winter to early spring. The results suggest that an accurate representation of the seasonal cycle of the wave geometry is necessary for the proper representation of downward wave coupling between the stratosphere and troposphere.

* Current affiliation: Lamont-Doherty Earth Observatory and Department of Applied Physics and Applied Mathematics, Columbia University, Palisades, New York

Corresponding author address: Dr. Tiffany A. Shaw, Center for Atmosphere Ocean Science, Courant Institute of Mathematical Sciences, New York University, 251 Mercer St., New York, NY 10012. Email: tshaw@cims.nyu.edu

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