Letter | Published:

Slowdown of the Walker circulation driven by tropical Indo-Pacific warming

Nature volume 491, pages 439443 (15 November 2012) | Download Citation


Global mean sea surface temperature (SST) has risen steadily over the past century1,2, but the overall pattern contains extensive and often uncertain spatial variations, with potentially important effects on regional precipitation3,4. Observations suggest a slowdown of the zonal atmospheric overturning circulation above the tropical Pacific Ocean (the Walker circulation) over the twentieth century1,5. Although this change has been attributed to a muted hydrological cycle forced by global warming5,6, the effect of SST warming patterns has not been explored and quantified1,7,8. Here we perform experiments using an atmospheric model, and find that SST warming patterns are the main cause of the weakened Walker circulation over the past six decades (1950–2009). The SST trend reconstructed from bucket-sampled SST and night-time marine surface air temperature features a reduced zonal gradient in the tropical Indo-Pacific Ocean, a change consistent with subsurface temperature observations8. Model experiments with this trend pattern robustly simulate the observed changes, including the Walker circulation slowdown and the eastward shift of atmospheric convection from the Indonesian maritime continent to the central tropical Pacific. Our results cannot establish whether the observed changes are due to natural variability or anthropogenic global warming, but they do show that the observed slowdown in the Walker circulation is presumably driven by oceanic rather than atmospheric processes.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    , & Twentieth century tropical sea surface temperature trends revisited. Geophys. Res. Lett.. 37, L10701, (2010)

  2. 2.

    , , , & Reassessing biases and other uncertainties in sea surface temperature observations measured in situ since 1850: 2. Biases and homogenization. J. Geophys. Res.. 116, D14104, (2011)

  3. 3.

    et al. Global warming pattern formation: sea surface temperature and rainfall. J. Clim. 23, 966–986 (2010)

  4. 4.

    & Critical influence of the pattern of tropical ocean warming on remote climate trends. Clim. Dyn. 36, 1577–1591 (2011)

  5. 5.

    et al. Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing. Nature 441, 73–76 (2006)

  6. 6.

    & Robust responses of the hydrological cycle to global warming. J. Clim. 19, 5686–5699 (2006)

  7. 7.

    & Global warming and the weakening of the tropical circulation. J. Clim. 20, 4316–4340 (2007)

  8. 8.

    et al. Regional patterns of tropical Indo-Pacific climate change: evidence of the Walker circulation weakening. J. Clim. 25, 1689–1710 (2012)

  9. 9.

    & What caused the observed twentieth-century weakening of the Walker circulation? J. Clim. 24, 6501–6514 (2011)

  10. 10.

    , & Reconciling differing views of tropical Pacific climate change. Eos 91, 141–142 (2010)

  11. 11.

    , & Rethinking the ocean’s role in the Southern Oscillation. J. Clim. 24, 4056–4072 (2011)

  12. 12.

    et al. Twentieth century Walker circulation change: data analysis and model experiments. Clim. Dyn. 38, 1757–1773 (2012)

  13. 13.

    et al. in Climate Change 2007: The Physical Science Basis (eds et al.). 747–845 (Cambridge Univ. Press, 2007)

  14. 14.

    & A verified estimation of the El Niño index Niño-3.4 since 1877. J. Clim. 22, 3979–3992 (2009)

  15. 15.

    et al. Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res.. 108, 4407, (2003)

  16. 16.

    , , & Improvements to NOAA’s historical merged land-ocean surface temperature analysis (1880–2006). J. Clim. 21, 2283–2296 (2008)

  17. 17.

    et al. ICOADS Release 2.5: extensions and enhancements to the surface marine meteorological archive. Int. J. Climatol. 31, 951–967 (2011)

  18. 18.

    et al. The NCEP/NCAR 40-year reanalysis project. Bull. Am. Meteorol. Soc. 77, 437–471 (1996)

  19. 19.

    et al. The ERA-40 re-analysis. Q. J. R. Meteorol. Soc. 131, 2961–3012 (2005)

  20. 20.

    et al. The twentieth century reanalysis project. Q. J. R. Meteorol. Soc. 137, 1–28 (2011)

  21. 21.

    & Changes in the sea surface temperature threshold for tropical convection. Nature Geosci. 3, 842–845 (2010)

  22. 22.

    , , , & Reassessing biases and other uncertainties in sea surface temperature observations measured in situ since 1850: 1. Measurement and sampling uncertainties. J. Geophys. Res.. 116, D14103, (2011)

  23. 23.

    & Simulation of the 1976/77 climate transition over the North Pacific: sensitivity to tropical forcing. J. Clim. 19, 6170–6180 (2006)

  24. 24.

    , & The mid-1970s climate shift in the Pacific and the relative roles of forced versus inherent decadal variability. J. Clim. 22, 780–792 (2009)

  25. 25.

    et al. Atmospheric brown clouds: impacts on South Asian climate and hydrological cycle. Proc. Natl Acad. Sci. USA 102, 5326–5333 (2005)

  26. 26.

    et al. Decadal shift in El Niño influences on Indo-western Pacific and East Asian climate in the 1970s. J. Clim. 23, 3352–3368 (2010)

  27. 27.

    The GFDL Global Atmospheric Model Development Team. The new GFDL global atmosphere and land model AM2–LM2: evaluation with prescribed SST simulations. J. Clim. 17, 4641–4673 (2004)

  28. 28.

    et al. The Atmospheric General Circulation Model ECHAM5. Part I: Model Description (MPI report 349, Max Planck Institute, 2003); available at (2003)

  29. 29.

    et al. The formulation and atmospheric simulation of the Community Atmosphere Model version 3 (CAM3). J. Clim. 19, 2144–2161 (2006)

  30. 30.

    et al. The mean climate of the Community Atmosphere Model (CAM4) in forced SST and fully coupled experiments. J. Clim. (submitted)

  31. 31.

    & A new globally complete monthly historical gridded mean sea level pressure dataset (HadSLP2): 1850-2004. J. Clim. 19, 5816–5842 (2006)

  32. 32.

    & Wave- and anemometer-based sea surface wind (WASWind) for climate change analysis. J. Clim. 24, 267–285 (2011)

  33. 33.

    , , & Global land precipitation: a 50-yr monthly analysis based on gauge observations. J. Hydrometeorol. 3, 249–266 (2002)

  34. 34.

    , , & Global Precipitation Analysis Products of the GPCC (Global Precipitation Climatology Centre, 2008); available at ftp://ftp-anon.dwd.de/pub/data/gpcc/PDF/GPCC_intro_products_2008.pdf (2008)

  35. 35.

    & Climatologically aided interpolation (CAI) of terrestrial air temperature. Int. J. Climatol. 15, 221–229 (1995)

  36. 36.

    , & Precipitation sensitivity to global warming: comparison of observations with HadCM2 simulations. Geophys. Res. Lett. 25, 3379–3382 (1998)

  37. 37.

    Estimates of the regression coefficient based on Kendall’s tau. J. Am. Stat. Assoc. 63, 1379–1389 (1968)

  38. 38.

    Rank Correlation Methods (Griffin, 1975)

Download references


We thank A. Timmermann for discussions, and X. T. Zheng and J. Ma for data processing. The work was supported by JAMSTEC, the National Basic Research Program of China (2012CB955600), NASA, NSF and NOAA. NCAR is sponsored by NSF.

Author information


  1. International Pacific Research Center, Department of Meteorology, SOEST, University of Hawaii at Manoa, 1680 East West Road, Honolulu, Hawaii 96822, USA

    • Hiroki Tokinaga
    •  & Shang-Ping Xie
  2. Physical Oceanography Laboratory, Ocean University of China, Qingdao 266003, China

    • Shang-Ping Xie
  3. National Center for Atmospheric Research, PO Box 3000, Boulder, Colorado 80307, USA

    • Clara Deser
  4. International Pacific Research Center, SOEST, University of Hawaii at Manoa, 1680 East West Road, Honolulu, Hawaii 96822, USA

    • Yu Kosaka
  5. Institute for Geophysics, The University of Texas at Austin, 10100 Burnet Road, Austin, Texas 78758, USA

    • Yuko M. Okumura


  1. Search for Hiroki Tokinaga in:

  2. Search for Shang-Ping Xie in:

  3. Search for Clara Deser in:

  4. Search for Yu Kosaka in:

  5. Search for Yuko M. Okumura in:


H.T., Y.K. and Y.M.O. designed and performed model experiments. S.-P.X. and C.D. supervised the work. H.T. analysed observations and model simulations. H.T., S.-P.X., C.D. and Y.M.O. wrote the manuscript, with feedback from all authors.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Hiroki Tokinaga or Shang-Ping Xie.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    This file contains Supplementary Text 1-4, Supplementary Figures 1-5 and additional references.

About this article

Publication history






Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Newsletter Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing