• Baquero-Bernal, A., M. Latif, and S. Legutke, 2002: On dipolelike variability of sea surface temperature in the tropical Indian Ocean. J. Climate, 15 , 13581368.

    • Search Google Scholar
    • Export Citation
  • Barnett, T., D. Pierce, M. Latif, D. Dommenget, and R. Saravanan, 1999: Interdecadal interactions between the Tropics and midlatitudes in the Pacific basin. Geophys. Res. Lett, 26 , 615618.

    • Search Google Scholar
    • Export Citation
  • Burgers, G., and D. B. Stephenson, 1999: The normality of El Niño. Geophys. Res. Lett, 26 , 10271030.

  • Clement, A. C., M. A. Cane, and R. Seager, 2001: An orbitally driven tropical source for abrupt climate change. J. Climate, 14 , 23692375.

    • Search Google Scholar
    • Export Citation
  • Federov, A., and S. Philander, 2000: Is El Niño changing? Science, 288 , 19972002.

  • Frey, H., M. Latif, and T. Stockdale, 1997: The coupled GCM ECHO-2. Part I: The tropical Pacific. Mon. Wea. Rev, 125 , 703720.

  • Graham, N. E., 1994: Decadal-scale climate variability in the tropical and North Pacific during the 1970s and 1980s: Observations and model results. Climate Dyn, 10 , 135162.

    • Search Google Scholar
    • Export Citation
  • Gu, D., and S. Philander, 1995: Secular changes of annual and interannual variability in the Tropics during the past century. J. Climate, 8 , 864876.

    • Search Google Scholar
    • Export Citation
  • Gu, D., and S. Philander, 1997: Interdecadal climate fluctuations that depend on exchanges between the Tropics and extratropics. Science, 275 , 805807.

    • Search Google Scholar
    • Export Citation
  • Hibler, W. D., 1979: A dynamic thermodynamic sea ice model. J. Phys. Oceanogr, 9 , 815846.

  • Kirtman, B., and P. Schopf, 1998: Decadal variability in ENSO predictability and prediction. J. Climate, 11 , 28042822.

  • Kirtman, B., and J. Shukla, 2002: Interactive coupled ensemble: A new coupling strategy for CGCMs. Geophys. Res. Lett.,29, 1367, doi:10.1029/2002GL014834.

    • Search Google Scholar
    • Export Citation
  • Kleeman, R., J. McCreary, and B. Klinger, 1999: A mechanism for the decadal variation of ENSO. Geophys. Res. Lett, 26 , 17431746.

  • Knutson, T. R., S. Manabe, and D. Gu, 1997: Simulated ENSO in a global coupled ocean–atmosphere model: Multidecadal amplitude modulation and CO2 sensitivity. J. Climate, 10 , 138161.

    • Search Google Scholar
    • Export Citation
  • Latif, M., and T. B. Barnett, 1994: Causes of decadal climate variability over the North Pacific and North America. Science, 266 , 634637.

    • Search Google Scholar
    • Export Citation
  • Latif, M., and T. B. Barnett, 1996: Decadal climate variability over the North Pacific and North America: Dynamics and predictability. J. Climate, 9 , 24072423.

    • Search Google Scholar
    • Export Citation
  • Latif, M., and Coauthors, 2004: Reconstructing, monitoring, and predicting multidecadal-scale changes in the North Atlantic thermohaline circulation with sea surface temperature. J. Climate, 17 , 16051614.

    • Search Google Scholar
    • Export Citation
  • Legutke, S., and E. Maier-Reimer, 1999: Climatology of the HOPE-G global ocean general circulation model. German Climate Computer Center (DKRZ) Tech. Rep. 21, 90 pp.

    • Search Google Scholar
    • Export Citation
  • Legutke, S., and R. Voss, 1999: The Hamburg atmosphere–ocean coupled circulation model ECHO-G. German Climate Computer Center (DKRZ) Tech. Rep. 18, 62 pp.

    • Search Google Scholar
    • Export Citation
  • Marsland, S. J., M. Latif, and S. Legutke, 2003: Antarctic circumpolar modes in a coupled ocean–atmosphere model. Ocean Dyn, 53 , 323331.

    • Search Google Scholar
    • Export Citation
  • McCreary, J., and P. Lu, 1994: Interaction between the subtropical and equatorial ocean circulations: The subtropical cell. J. Phys. Oceanogr, 24 , 466497.

    • Search Google Scholar
    • Export Citation
  • McPhaden, J. J., and D. Zhang, 2002: Slowdown of the meridional overturning circulation in the upper Pacific Ocean. Nature, 41 , 603608.

    • Search Google Scholar
    • Export Citation
  • Pacanowski, R. C., and S. G. H. Philander, 1981: Parameterization of vertical mixing in numerical models of tropical oceans. J. Phys. Oceanogr, 11 , 14431451.

    • Search Google Scholar
    • Export Citation
  • Parker, D. E., N. A. Rayner, E. B. Horton, and C. K. Folland, 1999: Development of the Hadley Centre sea ice and sea surface temperature data sets (HadISST). Proc. WMO Workshop on Advances in Marine Climatology—CLIMAR99, Vancouver, BC, Canada, WMO, 194–203.

    • Search Google Scholar
    • Export Citation
  • Rayner, N. A., E. B. Horton, D. E. Parker, C. K. Folland, and R. B. Hackett, 1996: Version 2.2 of the Global Sea-Ice and Sea Surface Temperature data set, 1903–1994. Hadley Centre Climate Research Tech. Note CRTN 74, 25 pp.

    • Search Google Scholar
    • Export Citation
  • Rodgers, K. B., M. Latif, and S. Legutke, 2000: Sensitivity of equatorial Pacific and Indian Ocean watermasses to the position of the Indonesian Throughflow. Geophys. Res. Lett, 27 , 29412944.

    • Search Google Scholar
    • Export Citation
  • Roeckner, E., and Coauthors, 1996: The atmospheric general circulation model ECHAM-4: Model description and simulation of present day climate. Max Planck Institute for Meteorology Tech. Rep. 218, 90 pp.

    • Search Google Scholar
    • Export Citation
  • Schneider, N., A. J. Miller, and D. W. Pierce, 2002: Anatomy of North Pacific decadal variability. J. Climate, 15 , 586605.

  • Smith, T. M., R. W. Reynolds, R. E. Livezey, and D. C. Stokes, 1996: Reconstruction of historical sea surface temperatures using empirical orthogonal functions. J. Climate, 9 , 14031420.

    • Search Google Scholar
    • Export Citation
  • Timmermann, A., 2003: Decadal ENSO amplitude modulations: A nonlinear paradigm. Global Planet. Change, 37 , 135156.

  • Timmermann, A., and F-F. Jin, 2002: A nonlinear mechanism for decadal El Niño amplitude changes. Geophys. Res. Lett.,29, 1003, doi:10.1029/ 2001GL013369.

    • Search Google Scholar
    • Export Citation
  • Timmermann, A., J. Oberhuber, A. Bacher, M. Esch, M. Latif, and E. Roeckner, 1999: Increased El Niño frequency in a climate model forced by future greenhouse warming. Nature, 398 , 694697.

    • Search Google Scholar
    • Export Citation
  • Timmermann, A., F-F. Jin, and J. Abschagen, 2003: A nonlinear theory for El Niño bursting. J. Atmos. Sci, 60 , 152165.

  • Torrence, C., and P. J. Webster, 1999: Interdecadal changes in the ENSO–monsoon system. J. Climate, 12 , 26792690.

  • Trenberth, K. E., and J. W. Hurrell, 1994: Decadal atmosphere–ocean variations in the Pacific. Climate Dyn, 9 , 303319.

  • Vimont, D. J., D. S. Battisti, and A. C. Hirst, 2002: Pacific interannual and interdecadal equatorial variability in a 1000-yr simulation of the CSIRO coupled general circulation model. J. Climate, 15 , 160178.

    • Search Google Scholar
    • Export Citation
  • White, W., Y. Tourre, and Y. Kushnir, 1999: Evolution of interdecadal variability in sea level pressure, sea surface temperature, and upper ocean temperature over the Pacific Ocean. J. Phys. Oceanogr, 29 , 15281541.

    • Search Google Scholar
    • Export Citation
  • Wolff, J-O., E. Maier-Reimer, and S. Legutke, 1997: The Hamburg Ocean Primitive Equation Model. German Climate Computer Center (DKRZ) Tech. Rep. 13, 98 pp.

    • Search Google Scholar
    • Export Citation
  • Wyrtki, K., and B. Kilonsky, 1984: Mean water and current structure during the Hawaii-to-Tahiti shuttle experiment. J. Phys. Oceanogr, 14 , 242254.

    • Search Google Scholar
    • Export Citation
  • Zebiak, S. E., and M. A. Cane, 1991: Natural climate variability in a coupled model. Workshop on Greenhouse-Gas-Induced Climate Change: A Critical Appraisal of Simulations and Observations, M. E. Schlesinger, Ed., Elsevier, 457–470.

    • Search Google Scholar
    • Export Citation
  • Zhang, Y., J. Wallace, and D. Battisti, 1997: ENSO-like interdecadal variability: 1900–1993. J. Climate, 10 , 10041020.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 478 212 12
PDF Downloads 326 201 9

Tropical Pacific Decadal Variability and Its Relation to Decadal Modulations of ENSO

View More View Less
  • 1 Laboratoire d'Océanographie Dynamique et de Climatologie, Paris, France
  • | 2 Meteorologisches Institut, Bonn, Germany
  • | 3 Institut fuer Meereskunde, Kiel, Germany
Restricted access

Abstract

A 1000-yr integration of a coupled ocean–atmosphere model (ECHO-G) has been analyzed to describe decadal to multidecadal variability in equatorial Pacific sea surface temperature (SST) and thermocline depth (Z20), and their relationship to decadal modulations of El Niño–Southern Oscillation (ENSO) behavior. Although the coupled model is characterized by an unrealistically regular 2-yr ENSO period, it exhibits significant modulations of ENSO amplitude on decadal to multidecadal time scales.

The authors' main finding is that the structures in SST and Z20 characteristic of tropical Pacific decadal variability (TPDV) in the model are due to an asymmetry between the anomaly patterns associated with the model's El Niño and La Niña states, with this asymmetry reflecting a nonlinearity in ENSO variability. As a result, the residual (i.e., the sum) of the composite El Niño and La Niña patterns exhibits a nonzero dipole structure across the equatorial Pacific, with positive perturbation values in the east and negative values in the west for SST and Z20. During periods when ENSO variability is strong, this difference manifests itself as a rectified change in the mean state.

For comparison, a similar analysis was applied to a gridded SST dataset spanning the period 1871–1999. The data confirms that the asymmetry between the SST anomaly patterns associated with El Niño and La Niña for the model is realistic. However, ENSO in the observations is weaker and not as regular as in the model, and thus the changes due to ENSO asymmetries for the observations can only be detected in the Niño-12 region.

Corresponding author address: Dr. Keith B. Rodgers, Laboratoire d'Océanographie Dynamique et de Climatologie, T45-55, 4E 4 pl. Jussieu-boite 100, 75252 Paris Cedex 05, France. Email: rodgers@lodyc.jussieu.fr

Abstract

A 1000-yr integration of a coupled ocean–atmosphere model (ECHO-G) has been analyzed to describe decadal to multidecadal variability in equatorial Pacific sea surface temperature (SST) and thermocline depth (Z20), and their relationship to decadal modulations of El Niño–Southern Oscillation (ENSO) behavior. Although the coupled model is characterized by an unrealistically regular 2-yr ENSO period, it exhibits significant modulations of ENSO amplitude on decadal to multidecadal time scales.

The authors' main finding is that the structures in SST and Z20 characteristic of tropical Pacific decadal variability (TPDV) in the model are due to an asymmetry between the anomaly patterns associated with the model's El Niño and La Niña states, with this asymmetry reflecting a nonlinearity in ENSO variability. As a result, the residual (i.e., the sum) of the composite El Niño and La Niña patterns exhibits a nonzero dipole structure across the equatorial Pacific, with positive perturbation values in the east and negative values in the west for SST and Z20. During periods when ENSO variability is strong, this difference manifests itself as a rectified change in the mean state.

For comparison, a similar analysis was applied to a gridded SST dataset spanning the period 1871–1999. The data confirms that the asymmetry between the SST anomaly patterns associated with El Niño and La Niña for the model is realistic. However, ENSO in the observations is weaker and not as regular as in the model, and thus the changes due to ENSO asymmetries for the observations can only be detected in the Niño-12 region.

Corresponding author address: Dr. Keith B. Rodgers, Laboratoire d'Océanographie Dynamique et de Climatologie, T45-55, 4E 4 pl. Jussieu-boite 100, 75252 Paris Cedex 05, France. Email: rodgers@lodyc.jussieu.fr

Save