Mean Climate Controls on the Simulated Response of ENSO to Increasing Greenhouse Gases

Pedro N. DiNezio International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, Hawaii

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Ben P. Kirtman Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida

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Amy C. Clement Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida

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Sang-Ki Lee Cooperative Institute for Marine and Atmospheric Studies, University of Miami, and NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida

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Gabriel A. Vecchi NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey

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Andrew Wittenberg NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey

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Abstract

Climate model experiments are analyzed to elucidate if and how the changes in mean climate in response to doubling of atmospheric CO2 (2xCO2) influence ENSO. The processes involved the development, transition, and decay of simulated ENSO events are quantified through a multimodel heat budget analysis. The simulated changes in ENSO amplitude in response to 2xCO2 are directly related to changes in the anomalous ocean heat flux convergence during the development, transition, and decay of ENSO events. The weakening of the Walker circulation and the increased thermal stratification, both robust features of the mean climate response to 2xCO2, play opposing roles in ENSO–mean climate interactions. Weaker upwelling in response to a weaker Walker circulation drives a reduction in thermocline-driven ocean heat flux convergence (i.e., thermocline feedback) and, thus, reduces the ENSO amplitude. Conversely, a stronger zonal subsurface temperature gradient, associated with the increased thermal stratification, drives an increase in zonal-current-induced ocean heat flux convergence (i.e., zonal advection feedback) and, thus, increases the ENSO amplitude. These opposing processes explain the lack of model agreement in whether ENSO is going to weaken or strengthen in response to increasing greenhouse gases, but also why ENSO appears to be relatively insensitive to 2xCO2 in most models.

Corresponding author address: Pedro N. DiNezio, International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, HI 96822. E-mail: pdn@hawaii.edu

Abstract

Climate model experiments are analyzed to elucidate if and how the changes in mean climate in response to doubling of atmospheric CO2 (2xCO2) influence ENSO. The processes involved the development, transition, and decay of simulated ENSO events are quantified through a multimodel heat budget analysis. The simulated changes in ENSO amplitude in response to 2xCO2 are directly related to changes in the anomalous ocean heat flux convergence during the development, transition, and decay of ENSO events. The weakening of the Walker circulation and the increased thermal stratification, both robust features of the mean climate response to 2xCO2, play opposing roles in ENSO–mean climate interactions. Weaker upwelling in response to a weaker Walker circulation drives a reduction in thermocline-driven ocean heat flux convergence (i.e., thermocline feedback) and, thus, reduces the ENSO amplitude. Conversely, a stronger zonal subsurface temperature gradient, associated with the increased thermal stratification, drives an increase in zonal-current-induced ocean heat flux convergence (i.e., zonal advection feedback) and, thus, increases the ENSO amplitude. These opposing processes explain the lack of model agreement in whether ENSO is going to weaken or strengthen in response to increasing greenhouse gases, but also why ENSO appears to be relatively insensitive to 2xCO2 in most models.

Corresponding author address: Pedro N. DiNezio, International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, HI 96822. E-mail: pdn@hawaii.edu
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  • An, S.-I., F.-F. Jin, 2004: Nonlinearity and asymmetry of ENSO. J. Climate, 17, 23992412.

  • An, S.-I., Y.-G. Ham, J.-S. Kug, F.-F. Jin, and I.-S. Kang, 2005: El Niño–La Niña asymmetry in the Coupled Model Intercomparison Project simulations. J. Climate, 18, 26172627.

    • Search Google Scholar
    • Export Citation
  • Battisti, D. S., 1988: Dynamics and thermodynamics of a warming event in a coupled tropical atmosphere–ocean model. J. Atmos. Sci., 45, 28892919.

    • Search Google Scholar
    • Export Citation
  • Battisti, D. S., A. C. Hirst, 1989: Interannual variability in a tropical atmosphere–ocean model: Influence of the basic state, ocean geometry and nonlinearity. J. Atmos. Sci., 46, 16871712.

    • Search Google Scholar
    • Export Citation
  • Clarke, A. J., 2010: Analytical theory for the quasi-steady and low-frequency equatorial ocean response to wind forcing: The “tilt” and “warm water volume” modes. J. Phys. Oceanogr., 40, 121137.

    • Search Google Scholar
    • Export Citation
  • Collins, M., and Coauthors, 2010: The impact of global warming on the tropical Pacific and El Niño. Nat. Geosci., 3, 391397.

  • Deser, C., A. Capotondi, R. Saravanan, and A. S. Phillips, 2006: Tropical Pacific and Atlantic climate variability in CCSM3. J. Climate, 19, 24512481.

    • Search Google Scholar
    • Export Citation
  • DiNezio, P., A. Clement, G. Vecchi, B. Soden, B. Kirtman, and S.-K. Lee, 2009: Climate response of the equatorial Pacific to global warming. J. Climate, 22, 48734892.

    • Search Google Scholar
    • Export Citation
  • Fedorov, A. V., and S. G. Philander, 2001: A stability analysis of tropical ocean–atmosphere interactions: Bridging measurements and theory for El Niño. J. Climate, 14, 30863101.

    • Search Google Scholar
    • Export Citation
  • Flato, G. M., and G. J. Boer, 2001: Warming asymmetry in climate change simulations. Geophys. Res. Lett., 28, 195198.

  • Grove, R., 1988: Global impact of the 1789-93 El Niño. Nature, 393, 318319.

  • Guilderson, T. P., and D. P. Schrag, 1998: Abrupt shift in subsurface temperatures in the tropical pacific associated with changes in El Niño. Science, 281, 240243.

    • Search Google Scholar
    • Export Citation
  • Guilyardi, E., 2006: El Niño-mean state-seasonal cycle interactions in a multi-model ensemble. Climate Dyn., 26, 329348.

  • Harrison, D. E., and N. K. Larkin, 1997: Darwin sea level pressure, 1876–1996: Evidence for climate change? Geophys. Res. Lett., 24, 17751782.

    • Search Google Scholar
    • Export Citation
  • Hasumi, H., and S. Emori, Eds., 2004: K-1 coupled GCM(MIROC) description. K-1 Tech. Rep. 1, 34 pp.

  • Jin, F.-F., 1997: An equatorial ocean recharge paradigm for ENSO. Part I: Conceptual model. J. Atmos. Sci., 54, 811829.

  • Jin, F.-F., S. An, A. Timmermann, and J. Zhao, 2003: Strong El Niño events and nonlinear dynamical heating. Geophys. Res. Lett., 30, 1120, doi:10.1029/2002GL016356.

    • Search Google Scholar
    • Export Citation
  • Jin, F.-F., S. T. Kim, and L. Bejarano, 2006: A coupled-stability index for ENSO. Geophys. Res. Lett., 33, L23708, doi:10.1029/2006GL027221.

    • Search Google Scholar
    • Export Citation
  • Kessler, W. S., 2002: Is ENSO a cycle or a series of events? Geophys. Res. Lett., 29, 2125, doi:10.1029/2002GL015924.

  • Kim, S.-T., and F.-F. Jin, 2011a: An ENSO stability analysis. Part I: Results from a hybrid coupled model. Climate Dyn., 36, 15931607 , doi:10.1007/s00382-010-0796-0.

    • Search Google Scholar
    • Export Citation
  • Kim, S.-T., and F.-F. Jin, 2011b: An ENSO stability analysis. Part II: Results from the twentieth and twenty-first century simulations of the CMIP3 models. Climate Dyn., 36, 16091627 , doi:10.1007/s00382-010-0872-5.

    • Search Google Scholar
    • Export Citation
  • Kirtman, B. P., 1997: Oceanic Rossby wave dynamics and the ENSO period in a coupled model. J. Climate, 10, 16901704.

  • Kirtman, B. P., K. Pegion, and S. Kinter, 2005: Internal atmospheric dynamics and climate variability. J. Atmos. Sci., 62, 22202233.

  • Lloyd, J., E. Guilyardi, H. Weller, and J. Slingo, 2009: The role of atmosphere feedbacks during ENSO in the CMIP3 models. Atmos. Sci. Lett., 10, 170176.

    • Search Google Scholar
    • Export Citation
  • Marti, O., and Coauthors, 2005: The new IPSL climate system model: IPSL-CM4. Institut Pierre Simon Laplace des Sciences de l’Environnement Global Note du Pole de Modelisation 26. [Available online at http://dods.ipsl.jussieu.fr/omamce/IPSLCM4/DocIPSLCM4/FILES/socIPSLCM4.pdf.]

  • McPhaden, M. J., and X. Yu, 1999: Equatorial waves and the 1997–98 El Niño. Geophys. Res. Lett., 26, 29612964.

  • Meehl, G. A., P. R. Gent, J. M. Arblaster, B. L. Otto-Bliesner, E. C. Brady, and A. Craig, 2001: Factors that affect the amplitude of El Niño in global coupled climate models. Climate Dyn., 17, 515526.

    • Search Google Scholar
    • Export Citation
  • Meehl, G. A., and Coauthors, 2007: Global climate projections. Climate Change 2007: The Physical Science Basis, S. Solomon et al., Eds., Cambridge University Press, 747–845.

  • Merryfield, W., 2006: Changes to ENSO under CO2 doubling in a multimodel ensemble. J. Climate, 19, 40094027.

  • Münnich, M., M. A. Cane, and S. E. Zebiak, 1991: A study of self-excited oscillations of the tropical ocean-atmosphere system. Part II: Nonlinear cases. J. Atmos. Sci., 48, 12381248.

    • Search Google Scholar
    • Export Citation
  • Neale, R. B., J. H. Richter, and M. Jochum, 2008: The impact of convection on ENSO: From a delayed oscillator to a series of events. J. Climate, 21, 59045924.

    • Search Google Scholar
    • Export Citation
  • Park, W., N. Keenlyside, M. Latif, A. Ströh, R. Redler, E. Roeckner, and G. Madec, 2009: Tropical Pacific climate and its response to global warming in the Kiel climate model. J. Climate, 22, 7192.

    • Search Google Scholar
    • Export Citation
  • Penland, C., and P. D. Sardeshmukh, 1995: The optimal growth of tropical sea surface temperature anomalies. J. Climate, 8, 19992024.

  • Philip, S. Y., and G. J. van Oldenborgh, 2006: Shifts in ENSO coupling processes under global warming. Geophys. Res. Lett., 33, L11704 , doi:10.1029/2006GL026196.

    • Search Google Scholar
    • Export Citation
  • Rajagopalan, B., U. Lall, and M. A. Cane, 1997: Anomalous ENSO occurrences: An alternative view. J. Climate, 10, 23512357.

  • Salas-Mélia, D., and Coauthors, 2005: Description and validation of the CNRM-CM3 global coupled model, CNRM Working Note 103, 35 pp.

  • Schopf, P. S., and M. J. Suarez, 1988: Vacillations in a coupled ocean–atmosphere model. J. Atmos. Sci., 45, 549566.

  • Spencer, H., R. Sutton, and J. M. Slingo, 2007: El Niño in a coupled climate model: Sensitivity to changes in mean state induced by heat flux and wind stress corrections. J. Climate, 20, 22732298.

    • Search Google Scholar
    • Export Citation
  • Suarez, M. J., and P. S. Schopf, 1988: A delayed action oscillator for ENSO. J. Atmos. Sci., 45, 32833287.

  • Sun, D.-Z., and T. Zhang, 2006: A regulatory effect of ENSO on the time-mean thermal stratification of the equatorial upper ocean. Geophys. Res. Lett., 33, L07710, doi:10.1029/2005GL025296.

    • Search Google Scholar
    • Export Citation
  • Thompson, C. J., and D. S. Battisti, 2000: A linear stochastic dynamical model of ENSO. Part I: Model development. J. Climate, 13, 28182832.

    • Search Google Scholar
    • Export Citation
  • Thompson, C. J., and D. S. Battisti, 2001: A linear stochastic dynamical model of ENSO. Part II: Analysis. J. Climate, 14, 445466.

  • Timmermann, A., J. Oberhuber, A. Bacher, M. Esch, and M. Latif, 1999: Increased El Niño frequency in a climate model forced by future greenhouse warming. Nature, 398, 694696.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., and T. J. Hoar, 1997: El Niño and climate change. Geophys. Res. Lett., 24, 30573060.

  • van Oldenborgh, G. J., S. Y. Philip, and M. Collins, 2005: El Niño in a changing climate: A multi-model study. Ocean Sci., 1, 8195.

  • Vecchi, G. A., and B. J. Soden, 2007: Global warming and the weakening of the tropical circulation. J. Climate, 20, 43164340.

  • Vecchi, G. A., and A. T. Wittenberg, 2010: El Niño and our future climate: Where do we stand? WIREs Climate Change, 1, 260270, doi:10.1002/wcc.33.

    • Search Google Scholar
    • Export Citation
  • Vecchi, G. A., B. J. Soden, A. T. Wittenberg, I. M. Held, A. Leetmaa, and M. J. Harrison, 2006: Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing. Nature, 441, 7376.

    • Search Google Scholar
    • Export Citation
  • Volodin, E. M., and N. A. Diansky, 2004: El Niño reproduction in coupled general circulation model. Russ. Meteor. Hydrol., 12, 514.

  • Wittenberg, A. T., 2009: Are historical records sufficient to constrain ENSO simulations? Geophys. Res. Lett., 36, L12702, doi:10.1029/2009GL038710.

    • Search Google Scholar
    • Export Citation
  • Wittenberg, A. T., A. Rosati, N.-C. Lau, and J. J. Ploshay, 2006: GFDL’s CM2 global coupled climate models. Part III: Tropical Pacific climate and ENSO. J. Climate, 19, 698722.

    • Search Google Scholar
    • Export Citation
  • Yu, Y. Q., X. H. Zhang, and Y. F. Guo, 2004: Global coupled ocean–atmosphere general circulation models in LASG/IAP. Adv. Atmos. Sci., 21, 444455.

    • Search Google Scholar
    • Export Citation
  • Yukimoto, S., and A. Noda, 2002: Improvements in the Meteorological Research Institute Global Ocean–Atmosphere Coupled GCM (MRI-CGCM2) and its climate sensitivity. NIES Tech. Rep. 10, 8 pp.

  • Zhang, Q., Y. Guan, and H. Yang, 2008: ENSO amplitude change in observation and coupled models. Adv. Atmos. Sci., 25, 361366.

  • Zhang, T., D.-Z. Sun, R. Neale, and P. J. Rasch, 2009: An evaluation of ENSO asymmetry in the Community Climate System Models: A view from the subsurface. J. Climate, 22, 59335961.

    • Search Google Scholar
    • Export Citation
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