Editorial Type:
Article
Article Type:
Research Article

A New Rossby Wave–Breaking Interpretation of the North Atlantic Oscillation

Tim Woollings Department of Meteorology, University of Reading, Reading, United Kingdom

Search for other papers by Tim Woollings in
Current site
Google Scholar
PubMed Close
,
Brian Hoskins Department of Meteorology, University of Reading, Reading, United Kingdom

Search for other papers by Brian Hoskins in
Current site
Google Scholar
PubMed Close
,
Mike Blackburn Walker Institute, Department of Meteorology, University of Reading, and National Centre for Atmospheric Science, Reading, United Kingdom

Search for other papers by Mike Blackburn in
Current site
Google Scholar
PubMed Close
, and
Paul Berrisford Walker Institute, Department of Meteorology, University of Reading, and National Centre for Atmospheric Science, Reading, United Kingdom

Search for other papers by Paul Berrisford in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Feb 2008
DOI:
https://doi.org/10.1175/2007JAS2347.1
Page(s):
609–626
Restricted access

Abstract

This paper proposes the hypothesis that the low-frequency variability of the North Atlantic Oscillation (NAO) arises as a result of variations in the occurrence of upper-level Rossby wave–breaking events over the North Atlantic. These events lead to synoptic situations similar to midlatitude blocking that are referred to as high-latitude blocking episodes. A positive NAO is envisaged as being a description of periods in which these episodes are infrequent and can be considered as a basic, unblocked situation. A negative NAO is a description of periods in which episodes occur frequently. A similar, but weaker, relationship exists between wave breaking over the Pacific and the west Pacific pattern.

Evidence is given to support this hypothesis by using a two-dimensional potential-vorticity-based index to identify wave breaking at various latitudes. This is applied to Northern Hemisphere winter data from the 40-yr ECMWF Re-Analysis (ERA-40), and the events identified are then related to the NAO.

Certain dynamical precursors are identified that appear to increase the likelihood of wave breaking. These suggest mechanisms by which variability in the tropical Pacific, and in the stratosphere, could affect the NAO.

Corresponding author address: Tim Woollings, Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading RG6 6BB, United Kingdom. Email: t.j.woollings@rdg.ac.uk

Abstract

This paper proposes the hypothesis that the low-frequency variability of the North Atlantic Oscillation (NAO) arises as a result of variations in the occurrence of upper-level Rossby wave–breaking events over the North Atlantic. These events lead to synoptic situations similar to midlatitude blocking that are referred to as high-latitude blocking episodes. A positive NAO is envisaged as being a description of periods in which these episodes are infrequent and can be considered as a basic, unblocked situation. A negative NAO is a description of periods in which episodes occur frequently. A similar, but weaker, relationship exists between wave breaking over the Pacific and the west Pacific pattern.

Evidence is given to support this hypothesis by using a two-dimensional potential-vorticity-based index to identify wave breaking at various latitudes. This is applied to Northern Hemisphere winter data from the 40-yr ECMWF Re-Analysis (ERA-40), and the events identified are then related to the NAO.

Certain dynamical precursors are identified that appear to increase the likelihood of wave breaking. These suggest mechanisms by which variability in the tropical Pacific, and in the stratosphere, could affect the NAO.

Corresponding author address: Tim Woollings, Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading RG6 6BB, United Kingdom. Email: t.j.woollings@rdg.ac.uk

Save
Cover Journal of the Atmospheric Sciences
Journal of the Atmospheric Sciences

  • Abatzoglou, J. T., and G. Magnusdottir, 2006: Opposing effects of reflective and nonreflective planetary wave breaking on the NAO. J. Atmos. Sci., 63 , 3448–3457.

    • Search Google Scholar
    • Export Citation

  • Ambaum, M. H. P., and B. J. Hoskins, 2002: The NAO troposphere–stratosphere connection. J. Climate, 15 , 1969–1978.

  • Ambrizzi, T., and B. J. Hoskins, 1997: Stationary Rossby-wave propagation in a baroclinic atmosphere. Quart. J. Roy. Meteor. Soc., 123 , 919–928.

    • Search Google Scholar
    • Export Citation

  • Barriopedro, D., R. García-Herrera, A. R. Lupo, and E. Hernández, 2006: A climatology of Northern Hemisphere blocking. J. Climate, 19 , 1042–1063.

    • Search Google Scholar
    • Export Citation

  • Benedict, J. J., S. Lee, and S. B. Feldstein, 2004: Synoptic view of the North Atlantic Oscillation. J. Atmos. Sci., 61 , 121–144.

  • Berrisford, P., B. J. Hoskins, and E. Tyrlis, 2007: Blocking and Rossby wave breaking on the dynamical tropopause in the Southern Hemisphere. J. Atmos. Sci., 64 , 2881–2898.

    • Search Google Scholar
    • Export Citation

  • Cheng, X., and J. M. Wallace, 1993: Cluster analysis of the Northern Hemisphere wintertime 500-hPa height field: Spatial patterns. J. Atmos. Sci., 50 , 2674–2696.

    • Search Google Scholar
    • Export Citation

  • Colucci, S. J., 1985: Explosive cyclogenesis and large-scale circulation changes: Implications for atmospheric blocking. J. Atmos. Sci., 42 , 2701–2717.

    • Search Google Scholar
    • Export Citation

  • Croci-Maspoli, M., C. Schwierz, and H. Davies, 2007: Atmospheric blocking: Space-time links to the NAO and PNA. Climate Dyn., 29 , 713–725.

    • Search Google Scholar
    • Export Citation

  • Deser, C., G. Magnusdottir, R. Saravanan, and A. Phillips, 2004: The effects of North Atlantic SST and sea ice anomalies on the winter circulation in CCM3. Part II: Direct and indirect components of the response. J. Climate, 17 , 877–889.

    • Search Google Scholar
    • Export Citation

  • Diao, Y., J. Li, and D. Luo, 2006: A new blocking index and its application: Blocking action in the Northern Hemisphere. J. Climate, 19 , 4819–4839.

    • Search Google Scholar
    • Export Citation

  • Feldstein, S. B., 2003: The dynamics of NAO teleconnection pattern growth and decay. Quart. J. Roy. Meteor. Soc., 129 , 901–924.

  • Franzke, C., S. Lee, and S. B. Feldstein, 2004: Is the North Atlantic Oscillation a breaking wave? J. Atmos. Sci., 61 , 145–160.

  • Hoerling, M. P., J. W. Hurrell, and T. Xu, 2001: Tropical origins for recent North Atlantic climate change. Science, 292 , 90–92.

  • Hoskins, B. J., and P. D. Sardeshmukh, 1987: A diagnostic study of the dynamics of the Northern Hemisphere winter of 1985–86. Quart. J. Roy. Meteor. Soc., 113 , 759–778.

    • Search Google Scholar
    • Export Citation

  • Huang, J., M. Ji, K. Higuchi, and A. Shabbar, 2006: Temporal structures of the North Atlantic Oscillation and its impact on the regional climate variability. Adv. Atmos. Sci., 23 , 23–32.

    • Search Google Scholar
    • Export Citation

  • Hurrell, J. W., 1995: Decadal trends in the North Atlantic Oscillation: Regional temperatures and precipitation. Science, 269 , 676–679.

    • Search Google Scholar
    • Export Citation

  • Kimoto, M., and M. Ghil, 1993: Multiple flow regimes in the Northern Hemisphere winter. Part I: Methodology and hemispheric regimes. J. Atmos. Sci., 50 , 2625–2643.

    • Search Google Scholar
    • Export Citation

  • Kucharski, F., F. Molteni, and A. Bracco, 2006: Decadal interactions between the western tropical Pacific and the North Atlantic Oscillation. Climate Dyn., 26 , 79–91.

    • Search Google Scholar
    • Export Citation

  • Lin, H., J. Derome, and G. Brunet, 2005: Tropical Pacific link to the two dominant patterns of atmospheric variability. Geophys. Res. Lett., 32 .L03801, doi:10.1029/2004GL021495.

    • Search Google Scholar
    • Export Citation

  • Löptien, U., and E. Ruprecht, 2005: Effect of synoptic systems on the variability of the North Atlantic Oscillation. Mon. Wea. Rev., 133 , 2894–2904.

    • Search Google Scholar
    • Export Citation

  • Luo, D., 2005: Why is the North Atlantic block more frequent and long-lived during the negative NAO phase? Geophys. Res. Lett., 32 .L20804, doi:10.1029/2005GL022927.

    • Search Google Scholar
    • Export Citation

  • Luo, D., A. R. Lupo, and H. Wan, 2007: Dynamics of eddy-driven low-frequency dipole modes. Part I: A simple model of North Atlantic Oscillations. J. Atmos. Sci., 64 , 3–28.

    • Search Google Scholar
    • Export Citation

  • Orlanski, I., 2003: Bifurcation in eddy life cycles: Implications for storm track variability. J. Atmos. Sci., 60 , 993–1023.

  • Pelly, J. L., and B. J. Hoskins, 2003: A new perspective on blocking. J. Atmos. Sci., 60 , 743–755.

  • Rogers, J. C., 1981: The North Pacific Oscillation. Int. J. Climatol., 1 , 39–57.

  • Scaife, A. A., J. R. Knight, G. K. Vallis, and C. K. Folland, 2005: A stratospheric influence on the winter NAO and North Atlantic surface climate. Geophys. Res. Lett., 32 .L18715, doi:10.1029/2005GL023226.

    • Search Google Scholar
    • Export Citation

  • Scherrer, S. C., M. Croci-Maspoli, C. Schwierz, and C. Appenzeller, 2006: Two-dimensional indices of atmospheric blocking and their statistical relationship with winter climate patterns in the Euro-Atlantic region. Int. J. Climatol., 26 , 233–249.

    • Search Google Scholar
    • Export Citation

  • Schwierz, C., M. Croci-Maspoli, and H. C. Davies, 2004: Perspicacious indicators of atmospheric blocking. Geophys. Res. Lett., 31 .L06125, doi:10.1029/2003GL019341.

    • Search Google Scholar
    • Export Citation

  • Shabbar, A., J. Huang, and K. Higuchi, 2001: The relationship between the wintertime North Atlantic Oscillation and blocking episodes in the North Atlantic. Int. J. Climatol., 21 , 355–369.

    • Search Google Scholar
    • Export Citation

  • Shutts, G. J., 1983: The propagation of eddies in diffluent jetstreams: Eddy vorticity forcing of ‘blocking’ flow fields. Quart. J. Roy. Meteor. Soc., 109 , 737–761.

    • Search Google Scholar
    • Export Citation

  • Thompson, D. W. J., and J. M. Wallace, 2000: Annular modes in the extratropical circulation. Part I: Month-to-month variability. J. Climate, 13 , 1000–1016.

    • Search Google Scholar
    • Export Citation

  • Thompson, D. W. J., S. Lee, and M. P. Baldwin, 2002: Atmospheric processes governing the Northern Hemisphere Annular Mode/North Atlantic Oscillation. The North Atlantic Oscillation: Climatic Significance and Environmental Impact, Geophys. Monogr., Vol. 134, Amer. Geophys. Union, 81–112.

    • Search Google Scholar
    • Export Citation

  • Thorncroft, C. D., B. J. Hoskins, and M. E. McIntyre, 1993: Two paradigms of baroclinic-wave life-cycle behaviour. Quart. J. Roy. Meteor. Soc., 119 , 17–55.

    • Search Google Scholar
    • Export Citation

  • Tibaldi, S., and F. Molteni, 1990: On the operational predictability of blocking. Tellus, 42A , 343–365.

  • Tyrlis, E., and B. J. Hoskins, 2008a: Aspects of Northern Hemisphere atmospheric blocking climatology. J. Atmos. Sci., in press.

  • Tyrlis, E., and B. J. Hoskins, 2008b: The morphology of Northern Hemisphere blocking. J. Atmos. Sci., in press.

  • Ulbrich, U., and M. Cristoph, 1999: A shift of the NAO and increasing storm track activity over Europe due to anthropogenic greenhouse gas forcing. Climate Dyn., 15 , 551–559.

    • Search Google Scholar
    • Export Citation

  • Uppala, S. M., and Coauthors, 2005: The ERA-40 re-analysis. Quart. J. Roy. Meteor. Soc., 131 , 2961–3012.

  • Vallis, G. K., and E. Gerber, 2007: Local and hemispheric dynamics of the North Atlantic Oscillation, annular patterns and the Zonal Index. Dyn. Atmos. Oceans, in press.

    • Search Google Scholar
    • Export Citation

  • Vallis, G. K., E. P. Gerber, P. J. Kushner, and B. A. Cash, 2004: A mechanism and simple dynamical model of the North Atlantic Oscillation and annular modes. J. Atmos. Sci., 61 , 264–280.

    • Search Google Scholar
    • Export Citation

  • van Loon, H., and J. C. Rogers, 1978: The seesaw in winter temperatures between Greenland and Northern Europe. Part I: General description. Mon. Wea. Rev., 106 , 296–310.

    • Search Google Scholar
    • Export Citation

  • Vautard, R., 1990: Multiple weather regimes over the North Atlantic: Analysis of precursors and successors. Mon. Wea. Rev., 118 , 2056–2081.

    • Search Google Scholar
    • Export Citation

  • Wallace, J. M., and D. S. Gutzler, 1981: Teleconnections in the geopotential height field during the Northern Hemisphere winter. Mon. Wea. Rev., 109 , 784–812.

    • Search Google Scholar
    • Export Citation

  • Wanner, H., S. Brönnimann, C. Casty, D. Gyalistras, J. Luterbacher, C. Schmutz, D. B. Stephenson, and E. Xoplaki, 2001: North Atlantic Oscillation—Concepts and studies. Surv. Geophys., 22 , 321–381.

    • Search Google Scholar
    • Export Citation

  • Wittman, M. A. H., A. J. Charlton, and L. M. Polvani, 2007: The effect of lower stratospheric shear on baroclinic instability. J. Atmos. Sci., 64 , 479–496.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 1950 841 163
PDF Downloads 1568 496 38