Editorial Type:
Article
Article Type:
Research Article

Winter North Atlantic Oscillation Hindcast Skill: 1900–2001

Christopher G. Fletcher Department of Space and Climate Physics, Benfield Hazard Research Centre, University College London, Surrey, United Kingdom

Search for other papers by Christopher G. Fletcher in
Current site
Google Scholar
PubMed Close
and
Mark A. Saunders Department of Space and Climate Physics, Benfield Hazard Research Centre, University College London, Surrey, United Kingdom

Search for other papers by Mark A. Saunders in
Current site
Google Scholar
PubMed Close
Print Publication:
15 Nov 2006
DOI:
https://doi.org/10.1175/JCLI3949.1
Page(s):
5762–5776
Restricted access

Abstract

Recent proposed seasonal hindcast skill estimates for the winter North Atlantic Oscillation (NAO) are derived from different lagged predictors, NAO indices, skill assessment periods, and skill validation methodologies. This creates confusion concerning what is the best-lagged predictor of the winter NAO. To rectify this situation, a standardized comparison of NAO cross-validated hindcast skill is performed against three NAO indices over three extended periods (1900–2001, 1950–2001, and 1972–2001). The lagged predictors comprise four previously published predictors involving anomalies in North Atlantic sea surface temperature (SST), Northern Hemisphere (NH) snow cover, and an additional predictor, an index of NH subpolar summer air temperature (TSP). Significant (p < 0.05) NAO hindcast skill is found with May SST 1900–2001, summer/autumn SST 1950–2001, and warm season snow cover 1972–2001. However, the highest and most significant hindcast skill for all periods and all NAO indices is achieved with TSP. Hindcast skill is nonstationary using all predictors and is highest during 1972–2001 with a TSP correlation skill of 0.59 and a mean-squared skill score of 35%. Observational evidence is presented to support a dynamical link between summer TSP and the winter NAO. Summer TSP is associated with a contemporaneous midlatitude zonal wind anomaly. This leads a pattern of North Atlantic SST that persists through autumn. Autumn SSTs may force a direct thermal NAO response or initiate a response via a third variable. These findings suggest that the NH subpolar regions may provide additional winter NAO lagged predictability alongside the midlatitudes and the Tropics.

* Current affiliation: Atmospheric Physics Group, Department of Physics, University of Toronto, Toronto, Ontario, Canada

Corresponding author address: Christopher Fletcher, Atmospheric Physics Group, Department of Physics, University of Toronto, 60 St. George St., Toronto, ON M5S 1A7, Canada. Email: cgf@atmosp.physics.utoronto.ca

Abstract

Recent proposed seasonal hindcast skill estimates for the winter North Atlantic Oscillation (NAO) are derived from different lagged predictors, NAO indices, skill assessment periods, and skill validation methodologies. This creates confusion concerning what is the best-lagged predictor of the winter NAO. To rectify this situation, a standardized comparison of NAO cross-validated hindcast skill is performed against three NAO indices over three extended periods (1900–2001, 1950–2001, and 1972–2001). The lagged predictors comprise four previously published predictors involving anomalies in North Atlantic sea surface temperature (SST), Northern Hemisphere (NH) snow cover, and an additional predictor, an index of NH subpolar summer air temperature (TSP). Significant (p < 0.05) NAO hindcast skill is found with May SST 1900–2001, summer/autumn SST 1950–2001, and warm season snow cover 1972–2001. However, the highest and most significant hindcast skill for all periods and all NAO indices is achieved with TSP. Hindcast skill is nonstationary using all predictors and is highest during 1972–2001 with a TSP correlation skill of 0.59 and a mean-squared skill score of 35%. Observational evidence is presented to support a dynamical link between summer TSP and the winter NAO. Summer TSP is associated with a contemporaneous midlatitude zonal wind anomaly. This leads a pattern of North Atlantic SST that persists through autumn. Autumn SSTs may force a direct thermal NAO response or initiate a response via a third variable. These findings suggest that the NH subpolar regions may provide additional winter NAO lagged predictability alongside the midlatitudes and the Tropics.

* Current affiliation: Atmospheric Physics Group, Department of Physics, University of Toronto, Toronto, Ontario, Canada

Corresponding author address: Christopher Fletcher, Atmospheric Physics Group, Department of Physics, University of Toronto, 60 St. George St., Toronto, ON M5S 1A7, Canada. Email: cgf@atmosp.physics.utoronto.ca

Save
Cover Journal of Climate
Journal of Climate

  • Barnston, A. G., and R. E. Livezey, 1987: Classification of seasonality and persistence of low-frequency atmospheric circulation patterns. Mon. Wea. Rev., 115 , 1083–1126.

    • Search Google Scholar
    • Export Citation

  • Basnett, T. A., and D. E. Parker, 1997: Development of the Global Mean Sea Level Pressure data set GMSLP2. Climate Research Tech. Note 79, Hadley Centre, Met Office, Exeter, Devon, United Kingdom, 16 pp. + appendixes.

  • Bloomfield, P., 2000: Fourier Analysis of Time Series. John Wiley and Sons, 288 pp.

  • Bojariu, R., and L. Gimeno, 2003: The role of snow cover fluctuations in multiannual NAO persistence. Geophys. Res. Lett., 30 .1156, doi:10.1029/2002GL015651.

    • Search Google Scholar
    • Export Citation

  • Cassou, C., C. Deser, L. Terray, J. W. Hurrell, and M. Drévillon, 2004: Summer sea surface temperature conditions in the North Atlantic and their impact upon the atmospheric circulation in early winter. J. Climate, 17 , 3349–3363.

    • Search Google Scholar
    • Export Citation

  • Cohen, J., and D. Entekhabi, 1999: Eurasian snow cover variability and northern hemisphere climate predictability. Geophys. Res. Lett., 26 , 345–348.

    • Search Google Scholar
    • Export Citation

  • Czaja, A., and C. Frankignoul, 2002: Observed impact of Atlantic SST anomalies on the North Atlantic Oscillation. J. Climate, 15 , 606–623.

    • Search Google Scholar
    • Export Citation

  • Davis, R. E., 1976: Predictability of sea surface temperature and sea level pressure anomalies over the North Pacific Ocean. J. Phys. Oceanogr., 6 , 249–266.

    • Search Google Scholar
    • Export Citation

  • Deser, C., and M. S. Timlin, 1997: Atmosphere–ocean interaction on weekly timescales in the North Atlantic and Pacific. J. Climate, 10 , 393–408.

    • Search Google Scholar
    • Export Citation

  • Drévillon, M., L. Terray, P. Rogel, and C. Cassou, 2001: Mid-latitude SST influence on European winter climate variability in the NCEP reanalysis. Climate Dyn., 18 , 331–344.

    • Search Google Scholar
    • Export Citation

  • Goddard, L., S. J. Mason, S. E. Zebiak, C. F. Ropelewski, R. Basher, and M. A. Cane, 2001: Current approaches to seasonal-to-interannual climate predictions. Int. J. Climatol., 21 , 1111–1152.

    • Search Google Scholar
    • Export Citation

  • Hilmer, M., and T. Jung, 2000: Evidence for a recent change in the link between the North Atlantic Oscillation and Arctic sea ice export. Geophys. Res. Lett., 27 , 989–992.

    • Search Google Scholar
    • Export Citation

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

    • Search Google Scholar
    • Export Citation

  • Hurrell, J. W., and H. van Loon, 1997: Decadal variations in climate associated with the North Atlantic Oscillation. Climatic Change, 36 , 301–326.

    • Search Google Scholar
    • Export Citation

  • Hurrell, J. W., M. P. Hoerling, A. S. Phillips, and T. Xu, 2004: Twentieth century North Atlantic climate change. Part I: Assessing determinism. Climate Dyn., 23 , 371–389.

    • Search Google Scholar
    • Export Citation

  • Johansson, A., A. Barnston, S. Saha, and H. Van den Dool, 1998: On the level and origin of seasonal forecast skill in northern Europe. J. Atmos. Sci., 55 , 103–127.

    • Search Google Scholar
    • Export Citation

  • Jones, P. D., and A. Moberg, 2003: Hemispheric and large-scale surface air temperature variations: An extensive revision and an update to 2001. J. Climate, 16 , 206–223.

    • Search Google Scholar
    • Export Citation

  • Jones, P. D., T. Jónsson, and D. Wheeler, 1997: Extension to the North Atlantic Oscillation using early instrumental pressure observations from Gibraltar and South-West Iceland. Int. J. Climatol., 17 , 1433–1450.

    • Search Google Scholar
    • Export Citation

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437–471.

  • Kitaev, L., A. Kislov, A. Krenke, V. Razuvaev, R. Martunganov, and I. Konstantinov, 2002: The snow cover characteristics of northern Eurasia and their relationship to climatic parameters. Boreal Environ. Res., 7 , 437–445.

    • Search Google Scholar
    • Export Citation

  • Kvamsto, N. G., P. Skeie, and D. B. Stephenson, 2004: Impact of Labrador sea-ice on the North Atlantic Oscillation. Int. J. Climatol., 24 , 603–612.

    • Search Google Scholar
    • Export Citation

  • Livezey, R. E., and W. Y. Chen, 1983: Statistical field significance and its determination by Monte Carlo techniques. Mon. Wea. Rev., 111 , 46–59.

    • Search Google Scholar
    • Export Citation

  • Manly, B. F. J., 1997: Randomization, Bootstrap and Monte Carlo Methods in Biology. 2d ed. Chapman and Hall, 424 pp.

  • Michaelsen, J., 1987: Cross-validation in statistical climate forecast models. J. Climate Appl. Meteor., 26 , 1589–1600.

  • Palmer, T. N., and Coauthors, 2004: Development of a European Multimodel Ensemble System for Seasonal-to-Interannual Prediction (DEMETER). Bull. Amer. Meteor. Soc., 85 , 853–872.

    • Search Google Scholar
    • Export Citation

  • Peng, S., and J. S. Whittaker, 1999: Mechanisms determining the atmospheric response to midlatitude SST anomalies. J. Climate, 12 , 1393–1408.

    • Search Google Scholar
    • Export Citation

  • Peng, S., W. A. Robinson, and S. Li, 2003: Mechanisms for the NAO response to the North Atlantic tripole. J. Climate, 16 , 1987–2004.

  • Polvani, L. M., and D. W. Waugh, 2004: Upward wave activity flux as precursor to extreme stratospheric events and subsequent anomalous surface weather regimes. J. Climate, 17 , 3548–3554.

    • Search Google Scholar
    • Export Citation

  • Rayner, N. A., D. E. Parker, E. B. Horton, C. K. Folland, L. K. Alexander, and D. P. Rowell, 2003: Global analyses of sea surface temperature, sea ice and night marine air temperature since the late nineteenth century. J. Geophys. Res., 108 .4407, doi:10.1029/2002JD002670.

    • Search Google Scholar
    • Export Citation

  • Robinson, D. A., K. F. Dewey, and R. R. Heim, 1993: Global snow cover monitoring: An update. Bull. Amer. Meteor. Soc., 74 , 1689–1696.

  • Robock, A., M. Mu, K. Y. Vinnikov, and D. Robinson, 2003: Land surface conditions over Eurasia and Indian summer monsoon rainfall. J. Geophys. Res., 108 .4131, doi:10.1029/2002JD002286.

    • Search Google Scholar
    • Export Citation

  • Rodwell, M. J., and C. K. Folland, 2002: Atlantic air-sea interaction and seasonal predictability. Quart. J. Roy. Meteor. Soc., 128 , 1413–1443.

    • Search Google Scholar
    • Export Citation

  • Rodwell, M. J., D. P. Rowell, and C. K. Folland, 1999: Oceanic forcing of the wintertime North Atlantic Oscillation and European climate. Nature, 398 , 320–323.

    • Search Google Scholar
    • Export Citation

  • Saunders, M. A., and B. Qian, 2002: Seasonal predictability of the winter NAO from North Atlantic sea surface temperatures. Geophys. Res. Lett., 29 .2049, doi:10.1029/2002GL014952.

    • Search Google Scholar
    • Export Citation

  • Saunders, M. A., B. Qian, and B. Lloyd-Hughes, 2003: Summer snow extent heralding of the winter North Atlantic Oscillation. Geophys. Res. Lett., 30 .1378, doi:10.1029/2003GL017401.

    • Search Google Scholar
    • Export Citation

  • Sutton, R. T., and D. L. R. Hodson, 2003: Influence of the ocean on North Atlantic climate variability 1871–1999. J. Climate, 16 , 3296–3313.

    • Search Google Scholar
    • Export Citation

  • Trigo, R. M., T. J. Osborn, and J. M. Corte-Real, 2002: The North Atlantic Oscillation influence on Europe: Climate impacts and associated physical mechanisms. Climate Res., 20 , 9–17.

    • Search Google Scholar
    • Export Citation

  • Walker, G. T., and E. W. Bliss, 1932: World weather V. Memo. Roy. Meteor. Soc., 4 , 53–84.

  • Wanner, H., S. Bronnimann, C. Casty, D. Gyalistras, J. Luterbacher, C. Schmultz, D. B. Stephenson, and E. Xoplaki, 2001: North Atlantic Oscillation—Concepts and studies. Surv. Geophys., 22 , 321–382.

    • Search Google Scholar
    • Export Citation

  • Wilks, D. S., 1995: Statistical Methods in the Atmospheric Sciences. Academic Press, 467 pp.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 126 61 4
PDF Downloads 54 24 1