A coupled method for initializing El Niño Southern Oscillation forecasts using sea surface temperature

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Keenlyside, Noel ; Latif, Mojib ; Botzet, Michael ; Jungclaus, Johann ; Schulzweida, Uwe (2005)

A simple method for initializing coupled general circulation models (CGCMs) using only sea surface temperature (SST) data is comprehensively tested in an extended set of ensemble hindcasts with the Max-Planck-Institute (MPI) climate model, MPI-OM/ECHAM5. In the scheme, initial conditions for both atmosphere and ocean are generated by running the coupled model with SST nudged strongly to observations. Air–sea interaction provides the mechanism through which SST influences the subsurface. Comparison with observations indicates that the scheme is performing well in the tropical Pacific. Results from a 500-yr control run show that the model's El Niño Southern Oscillation (ENSO) variability is quite realistic, in terms of strength, structure and period. The hindcasts performed were six months long, initiated four times per year, consisted of nine ensemble members, and covered the period 1969–2001. The ensemble was generated by only varying atmospheric initial conditions, which were sampled from the initialization run to capture intraseasonal variability. At six-month lead, the model is able to capture all the major ENSO extremes of the period. However, because of poor sampling of ocean initial conditions and model deficiencies, the ensemble-mean anomaly correlation skill for Niño3 SST is only 0.6 at six-month lead. None the less, the results presented here demonstrate the potential of such a simple scheme, and provide a simple method by which SST information may be better used in more complex initialization schemes.
  • References (41)
    41 references, page 1 of 5

    Barnston, A. G., Glantz, M. H. and He, Y. 1999. Predictive skill of statistical and dynamical climate models in SST forecasts during the 1997-98 El Nin˜o episode and the 1998 La Nin˜a onset. Bull. Am. Meteorol. Soc. 80, 217-243.

    Burgers, G., Balmaseda, M. A., Vossepoel, F. C., van Oldenborgh, G. J. and van Leeuwen, P. J. 2002. Balanced ocean-data assimilation near the equator. J. Phys. Oceanogr. 32, 2509-2529.

    Davey, M., Huddleston, M., Sperber, K. R., Braconnot, P., Bryan, F. and co-authors. 2002. STOIC: a study of coupled model climatology and variability in tropical ocean regions. Climate Dyn. 18, 403-420.

    Delecluse, P., Davey, M. K., Kitamura, Y., Philander, S. G. H., Suarez, M. and co-authors. 1998. Coupled general circulation modeling of the tropical Pacific. J. Geophys. Res. 103, 14 357-14 373.

    Enfield, D. B. and Mayer, D. A. 1997. Tropical Atlantic sea surface temperature variability and its relation to El Nin˜o Southern Oscillation. J. Geophys. Res. 102, 929-945.

    Guilyardi, E., Gualdi, S., Slingo, J. M., Navarra, A., Delecluse, P. and co-authors. 2004. Representing El Nin˜o in coupled ocean-atmosphere GCMs: the dominant role of the atmospheric component. J. Climate 17, 4623-4629.

    Hellerman, S. and Rosenstein, M. 1983. Normal monthly wind stress over the world ocean with error estimates. J. Phys. Oceanogr. 13, 1093-1104.

    Hibler, W. D. 1979. A dynamic thermodynamic sea-ice model. J. Phys. Oceanogr. 9, 815-846.

    Ji, M. and Leetmaa, A. 1997. Impact of data assimilation on ocean initialization and El Nin˜o prediction. Mon. Wea. Rev. 125, 742- 753.

    Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deaven, D. and coauthors. 1996. The NCEP/NCAR 40-year reanalysis project. Bull. Am. Meteorol. Soc. 77, 437-471.

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