Climate Dynamics

, Volume 30, Issue 6, pp 643–656 | Cite as

The variation of ENSO characteristics associated with atmospheric parameter perturbations in a coupled model

  • Thomas Toniazzo
  • Matthew Collins
  • Josephine Brown


We analyse the differences in the properties of the El Niño Southern Oscillation (ENSO) in a set of 17 coupled integrations with the flux-adjusted, 19-level HadCM3 model with perturbed atmospheric parameters. Within this ensemble, the standard deviation of the NINO3.4 deseasonalised SSTs ranges from 0.6 to 1.3 K. The systematic changes in the properties of the ENSO with increasing amplitude confirm that ENSO in HadCM3 is prevalently a surface (or SST) mode. The tropical-Pacific SST variability in the ensemble of coupled integrations correlates positively with the SST variability in the corresponding ensemble of atmosphere models coupled with a static mixed-layer ocean (“slab” models) perturbed with the same changes in atmospheric parameters. Comparison with the respective coupled ENSO-neutral climatologies and with the slab-model climatologies indicates low-cloud cover to be an important controlling factor of the strength of the ENSO within the ensemble. Our analysis suggests that, in the HadCM3 model, increased SST variability localised in the south-east tropical Pacific, not originating from ENSO and associated with increased amounts of tropical stratocumulus cloud, causes increased ENSO variability via an atmospheric bridge mechanism. The relationship with cloud cover also results in a negative correlation between the ENSO activity and the model’s climate sensitivity to doubling CO2.


Ensemble Member Flux Adjustment Thermocline Feedback 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The authors wish to thank Ben Booth and Glen Harris for their help in making the ensemble data available to us. The model integrations were performed at the Hadley Centre by the QUMP team. This work was supported by the UK Department of the Environment, Food and Rural Affairs under Contract PECD 7/12/37, by the Government Meteorological Research Contract, by the National Centre for Atmospheric Sciences (NCAS-Climate), and by the EU DYNAMITE project (contract 003903-GOCE).


  1. AchutaRao K, Sperber KR (2006) ENSO simulation in coupled ocean–atmosphere models: are the current models better? Clim Dyn 27:1–15CrossRefGoogle Scholar
  2. Bony S, Dufresne J-L (2005) Marine boundary layer clouds at the heart of tropical cloud feedback uncertainties in climate models. Geophys Res Lett 32:L20806. doi: 10.1029/2005GL023851 CrossRefGoogle Scholar
  3. Brown J, Collins M, Tudhope AW, Toniazzo T (2007) Modelling mid-Holocene tropical climate and ENSO variability: towards constraining predictions of future change with palaeo-data, 2007. Clim Dyn. doi: 10.1007/s00382-007-0270-9
  4. Capotondi A, Wittenberg A, Masina S (2005) Spatial and temporal structure of Tropical Pacific interannual variability in 20th century coupled simulations. Ocean Model 15:274–298CrossRefGoogle Scholar
  5. Coelho CAS, Stephenson DB, Doblas-Reyes FJ, Balmaseda M (2006) The skill of empirical and combined/calibrated coupled multi-model South American seasonal predictions during ENSO. Adv Geosci 6:51–55Google Scholar
  6. Collins M, Tett SFB, Cooper C (2001) The internal climate variability of HadCM3, a version of the Hadley Centre coupled model without flux adjustments. Clim Dyn 17:61–81CrossRefGoogle Scholar
  7. Collins M, Booth BBB, Harris GR, Murphy JM, Sexton DMH, Webb MJ (2006a) Towards quantifying uncertainty in transient climate change. Clim Dyn 27:127–147CrossRefGoogle Scholar
  8. Collins M, Bhaskaran B, Booth B, Harris G, Murphy J, Sexton D, Webb M, Brierley C (2006b) Progress and plans for probabilistic climate prediction at the Hadley Centre. Geophys Res Abstracts, vol 8, 05738, 2006Google Scholar
  9. Gordon C, Cooper C, Senior CA, Banks H, Gregory JM, Johns TC, Mitchell JFB, Wood RA (2000) The simulation of SST, sea ice extents and ocean heat transport in a version of the Hadley Centre coupled model without flux adjustments. Clim Dyn 16:147–168CrossRefGoogle Scholar
  10. Guilyardi E (2006) El Niõ-mean state-seasonal cycle interactions in a multi-model ensemble. Clim Dyn 26:329–348CrossRefGoogle Scholar
  11. Guilyardi E, Gualdi S, Slingo J, Navarra A, Delecluse P, Cole J, Madec G, Roberts M, Latif M, Terray L (2004) Representing El Niño in coupled ocean-atmosphere GCMs: the dominant role of the atmospheric component. J Clim 17:4623–4629CrossRefGoogle Scholar
  12. Jin F-F, Neelin JD (1993) Modes of interannual tropical ocean–atmosphere interaction—a unified view, III, Analytical results in fully coupled cases. J Atmos Sci 50:3523–3540CrossRefGoogle Scholar
  13. Johns TC, Carnell RE, Crossley JF, Gregory JM, Mitchell JFB, Senior CA, Tett SFB, Wood RA (1997) The second Hadley Centre coupled ocean-atmosphere GCM: model description, spin-up and validation. Clim Dyn 13:103–134CrossRefGoogle Scholar
  14. Joseph R, Nigam S (2006) ENSO evolution and teleconnections in IPCC’s twentieth-century climate simulations: realistic representation? J Clim 19:4360–4377CrossRefGoogle Scholar
  15. Merryfield WJ (2006) Changes to ENSO under CO2 doubling in a multi-model ensemble. J Clim 19:4009–4027CrossRefGoogle Scholar
  16. Murphy JM, Sexton DMH, Barnett DN, Jones GS, Webb MJ, Collins M, Stainforth DJ (2004) Quantification of modelling uncertainties in a large ensemble of climate change simulations. Nature 430:768–772CrossRefGoogle Scholar
  17. Philip SY, van Oldenborgh GJ (2006) Shifts in ENSO coupling processes under global warming. Geophys Res Lett 33:L11704. doi: 10.1029/2006GL026196 CrossRefGoogle Scholar
  18. Rayner NA et al (2003) Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J Geophys Res 108 doi: 10.1029/2002JD002670
  19. Spencer H, Sutton R, Slingo JM (2007) El Niño in a coupled climate model: sensitivity to changes in mean state induced by heat flux and wind stress corrections. J Clim 20:2273–2298CrossRefGoogle Scholar
  20. Toniazzo T (2005) A study of the sensitivity of ENSO to the mean climate. Adv Geosci 6:111–118Google Scholar
  21. Toniazzo T (2006) Properties of El Niño Southern Oscillation in different equilibrium climates with HadCM3. J Clim 19:4854–4876CrossRefGoogle Scholar
  22. van Oldeborgh GJ, Philip SY, Collins M (2005) El Niño in a changing climate: a multi-model study. Ocean Sci 1:81–95CrossRefGoogle Scholar
  23. Webb MJ, Senior CA, Sexton DMH, Ingram WJ, Williams KD, Ringer MA, McAvaney BJ, Colman R, Soden BJ, Gudgel R, Knutson T, Emori S, Ogura T, Tsushima Y, Andronova N, Li B, Musat I, Bony S, Taylor KE (2006) On the contribution of local feedback mechanisms to the range of climate sensitivity in two GCM ensembles. Clim Dyn 27:17–38CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Thomas Toniazzo
    • 1
  • Matthew Collins
    • 2
  • Josephine Brown
    • 3
  1. 1.The Walker Institute, Department of MeteorologyUniversity of ReadingReadingUK
  2. 2.Hadley Centre for Climate Prediction and Research, Met OfficeExeterUK
  3. 3.School of Geography and Environmental ScienceMonash UniversityClaytonAustralia

Personalised recommendations