Editorial Type:
Article
Article Type:
Research Article

Circulation Regimes and SST Forcing: Results from Large GCM Ensembles

David M. Straus George Mason University, Fairfax, Virginia, and Center for Ocean–Land–Atmosphere Studies, Calverton, Maryland

Search for other papers by David M. Straus in
Current site
Google Scholar
PubMed Close
and
Franco Molteni International Centre for Theoretical Physics, Trieste, Italy

Search for other papers by Franco Molteni in
Current site
Google Scholar
PubMed Close
Print Publication:
15 Apr 2004
DOI:
https://doi.org/10.1175/1520-0442(2004)017<1641:CRASFR>2.0.CO;2
Page(s):
1641–1656
Restricted access

Abstract

The purpose of this paper is to study the influence of tropical sea surface temperature (SST) on the midlatitude circulation regime behavior in the Pacific–North American region. Toward this end, a cluster analysis has been applied to 55-member ensembles of winter seasonal simulations of the Center for Ocean–Land–Atmosphere Studies general circulation model for 18 winters. The ensemble members for each winter utilize the same prescribed, observed weekly varying SST for that winter. The cluster analysis includes all fluctuations with time scales longer than 10 days except for the ensemble mean seasonal cycle.

Using a partitioning algorithm separately applied to each winter's ensemble, clusters are found in the 200-hPa height field that are signicant (vis-à-vis a suitable Gaussian background), reproducible (in half-length datasets), and consistent (with clusters obtained from the 200-hPa u wind) for all winters except the strong El Niño events of 1982/83, 1986/87, and 1997/98.

One cluster found consistently in many winters, consisting of a strong ridge over the Alaskan region and a trough over central North America, is quite similar to the Alaskan pattern identified from observations as being particularly difficult to predict and that occurs preferentially during La Niña events. Two other clusters found in many winters have no observational counterparts. A regime that is very similar to the seasonal mean response to cold tropical Pacific SSTs is seen during several La Niña winters.

A strong negative correlation between a measure of the strength of the clustering and the Niño-3 SST index is found. That this correlation is as strong as the correlation between the seasonal mean response and the same SST index indicates that the El Niño–Southern Oscillation–related SSTs affect the regime structure of intraseasonal flow as strongly as they do the mean state.

Corresponding author address: David Strauss, Center for Ocean–Land–Atmosphere Studies, 4041 Powder Mill Rd., Suite 302, Calverton, MD 20705 Email: straus@cola.iges.org

Abstract

The purpose of this paper is to study the influence of tropical sea surface temperature (SST) on the midlatitude circulation regime behavior in the Pacific–North American region. Toward this end, a cluster analysis has been applied to 55-member ensembles of winter seasonal simulations of the Center for Ocean–Land–Atmosphere Studies general circulation model for 18 winters. The ensemble members for each winter utilize the same prescribed, observed weekly varying SST for that winter. The cluster analysis includes all fluctuations with time scales longer than 10 days except for the ensemble mean seasonal cycle.

Using a partitioning algorithm separately applied to each winter's ensemble, clusters are found in the 200-hPa height field that are signicant (vis-à-vis a suitable Gaussian background), reproducible (in half-length datasets), and consistent (with clusters obtained from the 200-hPa u wind) for all winters except the strong El Niño events of 1982/83, 1986/87, and 1997/98.

One cluster found consistently in many winters, consisting of a strong ridge over the Alaskan region and a trough over central North America, is quite similar to the Alaskan pattern identified from observations as being particularly difficult to predict and that occurs preferentially during La Niña events. Two other clusters found in many winters have no observational counterparts. A regime that is very similar to the seasonal mean response to cold tropical Pacific SSTs is seen during several La Niña winters.

A strong negative correlation between a measure of the strength of the clustering and the Niño-3 SST index is found. That this correlation is as strong as the correlation between the seasonal mean response and the same SST index indicates that the El Niño–Southern Oscillation–related SSTs affect the regime structure of intraseasonal flow as strongly as they do the mean state.

Corresponding author address: David Strauss, Center for Ocean–Land–Atmosphere Studies, 4041 Powder Mill Rd., Suite 302, Calverton, MD 20705 Email: straus@cola.iges.org

Save
Cover Journal of Climate
Journal of Climate

  • Chen, W. Y., and H. M. van den Dool, 1997: Asymmetric impact of tropical SST anomalies on atmospheric internal variability over the North Pacific. J. Atmos. Sci., 54 , 725–740.

    • Search Google Scholar
    • Export Citation

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

    • Search Google Scholar
    • Export Citation

  • Compo, G. P., P. D. Sardeshmukh, and C. Penland, 2001: Changes of subseasonal variability associated with El Niño. J. Climate, 14 , 3356–3374.

    • Search Google Scholar
    • Export Citation

  • Corti, S., F. Molteni, and T. N. Palmer, 1999: Signature of recent climate change in frequencies of natural atmospheric circulation regimes. Nature, 398 , 799–802.

    • Search Google Scholar
    • Export Citation

  • Dole, R. M., 1986: Persistent anomalies of the extratropical Northern Hemisphere wintertime circulation: Structure. Mon. Wea. Rev., 114 , 178–207.

    • Search Google Scholar
    • Export Citation

  • Duchon, C., 1979: Lanczos filtering in one and two dimensions. J. Appl. Meteor., 18 , 1016–1022.

  • Haines, K., and A. Hannachi, 1995: Weather regimes in the Pacific from a GCM. J. Atmos. Sci., 52 , 2444–2462.

  • Higgins, R. W., and K. C. Mo, 1997: Persistent North Pacific circulation anomalies and the tropical intraseasonal oscillation. J. Climate, 10 , 223–244.

    • Search Google Scholar
    • Export Citation

  • Jenkins, G. M., and D. G. Watts, 1968: Spectral Analysis and Its Applications. Holden-Day, 525 pp.

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437–472.

  • Kiehl, J. T., J. J. Hack, G. Bonan, B. A. Boville, D. L. Williamson, and P. J. Rasch, 1998: The National Center for Atmospheric Research Community Climate Model: CCM3. J. Climate, 11 , 1131–1149.

    • Search Google Scholar
    • Export Citation

  • Kimoto, M., 1989: Multiple flow regimes in the Northern Hemisphere winter. Ph.D. thesis, University of California, Los Angeles, 180 pp.

  • Kimoto, M., and M. Ghil, 1993a: 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

  • Kimoto, M., and M. Ghil, 1993b: Multiple flow regimes in the Northern Hemisphere winter. Part II: Sectorial regimes and preferred transitions. J. Atmos. Sci., 50 , 2645–2673.

    • Search Google Scholar
    • Export Citation

  • McLachlan, G. J., and K. E. Basford, 1988: Mixture Models: Inference and Applications to Clustering. Marcel Dekker, 253 pp.

  • Michelangeli, P-A., R. Vautard, and B. Legras, 1995: Weather regimes: Recurrence and quasi-stationarity. J. Atmos. Sci., 52 , 1237–1256.

    • Search Google Scholar
    • Export Citation

  • Molteni, F., and S. Corti, 1998: Long-term fluctuations of the statistical properties of low-frequency variability: Dynamical origin and predictability. Quart. J. Roy. Meteor. Soc., 124 , 495–526.

    • Search Google Scholar
    • Export Citation

  • Moorthi, S., and M. J. Suarez, 1992: Relaxed Arakawa–Schubert: A parameterization of moist convection for general circulation models. Mon. Wea. Rev., 120 , 978–1002.

    • Search Google Scholar
    • Export Citation

  • Nakamura, H., M. Nakamura, and J. L. Anderson, 1997: The role of high- and low-frequency dynamics in blocking formation. Mon. Wea. Rev., 125 , 2074–2093.

    • Search Google Scholar
    • Export Citation

  • Renwick, J. A., and J. M. Wallace, 1996a: The influence of sampling variability upon model output error statistics. Mon. Wea. Rev., 124 , 1981–1991.

    • Search Google Scholar
    • Export Citation

  • Renwick, J. A., and J. M. Wallace, 1996b: Relationships between North Pacific wintertime blocking, El Niño, and the PNA. Mon. Wea. Rev., 124 , 2071–2076.

    • Search Google Scholar
    • Export Citation

  • Reynolds, R. W., and T. M. Smith, 1994: Improved global sea surface temperature analyses using optimal interpolation. J. Climate, 7 , 929–948.

    • Search Google Scholar
    • Export Citation

  • Sardeshmukh, P. D., G. P. Compo, and C. Penland, 2000: Changes of probability associated with El Niño. J. Climate, 13 , 4268–4286.

  • Schneider, E. K., 2002: Understanding differences between the equatorial Pacific as simulated by two coupled GCMs. J. Climate, 15 , 449–469.

    • Search Google Scholar
    • Export Citation

  • Shukla, J., D. A. Paolino, D. M. Straus, D. DeWitt, M. Fennessy, J. L. Kinter, L. Marx, and R. Mo, 2000: Dynamical seasonal prediction with the COLA atmospheric model. Quart. J. Roy. Meteor. Soc., 126 , 2265–2291.

    • Search Google Scholar
    • Export Citation

  • Silverman, B. W., 1986: Density Estimation for Statistics and Data Analysis. Chapman and Hall, 175 pp.

  • Smyth, P., K. Ide, and M. Ghil, 1999: Multiple regimes in Northern Hemisphere height fields via mixture model clustering. J. Atmos. Sci., 56 , 3704–3723.

    • Search Google Scholar
    • Export Citation

  • Snedecor, G. W., and W. G. Cochran, 1978: Statistical Methods. 6th ed. Iowa State University Press, 593 pp.

  • Straus, D. M., 1983: On the role of the seasonal cycle. J. Atmos. Sci., 40 , 303–313.

  • Straus, D. M., and J. Shukla, 1997: Variations of midlatitude transient dynamics associated with ENSO. J. Atmos. Sci., 54 , 777–790.

  • Straus, D. M., and J. Shukla, 2002: Does ENSO force the PNA? J. Climate, 15 , 2340–2358.

  • Toth, Z., 1991: The effect of tropical SST on multiple equilibria in the NH extratropical circulation phase space. Preprints, Fifth Conf. on Climate Variations, Denver, CO, Amer. Meteor. Soc., 429–432.

    • Search Google Scholar
    • Export Citation

  • Toth, Z., 1993a: Preferred and unpreferred circulation types in the Northern Hemisphere wintertime phase space. J. Atmos. Sci., 50 , 2868–2888.

    • Search Google Scholar
    • Export Citation

  • Toth, Z., 1993b: Preferred extratropical circulation types: ENSO-induced or intrinsic? Preprints, 18th Annual Climate Diagnostics Workshop, Boulder, CO, Amer. Meteor. Soc., 171–174.

    • Search Google Scholar
    • Export Citation

  • Trenberth, K. E., and J. W. Hurrell, 1994: Decadal atmosphere–ocean variations in the Pacific. Climate Dyn., 9 , 303–319.

  • Xue, Y-K., P. J. Sellers, J. L. Kinter, and J. Shukla, 1991: A simplified biosphere model for global climate studies. J. Climate, 4 , 345–364.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 649 333 34
PDF Downloads 162 41 4