Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing

Abstract

Since the mid-nineteenth century the Earth's surface has warmed1,2,3, and models indicate that human activities have caused part of the warming by altering the radiative balance of the atmosphere1,3. Simple theories suggest that global warming will reduce the strength of the mean tropical atmospheric circulation4,5. An important aspect of this tropical circulation is a large-scale zonal (east–west) overturning of air across the equatorial Pacific Ocean—driven by convection to the west and subsidence to the east—known as the Walker circulation6. Here we explore changes in tropical Pacific circulation since the mid-nineteenth century using observations and a suite of global climate model experiments. Observed Indo-Pacific sea level pressure reveals a weakening of the Walker circulation. The size of this trend is consistent with theoretical predictions, is accurately reproduced by climate model simulations and, within the climate models, is largely due to anthropogenic forcing. The climate model indicates that the weakened surface winds have altered the thermal structure and circulation of the tropical Pacific Ocean. These results support model projections of further weakening of tropical atmospheric circulation during the twenty-first century4,5,7.

This is a preview of subscription content

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Spatial pattern of observed and modelled sea level pressure linear trends.
Figure 2: Summary of the linear trends in SLP gradient across the Indo-Pacific (ΔSLP) from observations and the various GCM historical radiative forcing experiments.
Figure 3: Observed and modelled evolution of ΔSLP since the nineteenth century.
Figure 4: Observed and modelled equatorial Pacific zonal-mean zonal wind-stress anomaly, < τx > , and equatorial thermocline depth anomaly, Ztc.

References

  1. Houghton, J., et al. Climate Change 2001: The Scientific Basis (Cambridge Univ. Press, Cambridge, UK, 2001)

    Google Scholar 

  2. Rayner, N. A. et al. Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res. 108(D14), 4407, doi:10.1029/2002JD002670 (2003)

    Article  Google Scholar 

  3. Knutson, T. R. et al. Assessment of twentieth-century regional surface temperature trends using the GFDL CM2 coupled models. J. Clim. (in the press)

  4. Held, I. M. & Soden, B. J. Robust responses of the hydrological cycle to global warming. J. Clim. (in the press)

  5. Knutson, T. R. & Manabe, S. Time-mean response over the tropical Pacific to increased CO2 in a coupled ocean-atmosphere model. J. Clim. 8, 2181–2199 (1995)

    ADS  Article  Google Scholar 

  6. Julian, P. R. & Chervin, R. M. A study of the Southern Oscillation and the Walker Circulation. Mon. Weath. Rev. 106, 1433–1451 (1978)

    ADS  Article  Google Scholar 

  7. Tanaka, H. L., Ishizki, N. & Kitoh, A. Trend and interannual variability of Walker, monsoon and Hadley circulations defined by velocity potential in the upper troposphere. Tellus A 56, 250–269 (2004)

    ADS  Article  Google Scholar 

  8. Webster, P. J. et al. Monsoons: Processes, predictability, and the prospects for prediction. J. Geophys. Res. 103(C7), 14451–14510 (1998)

    ADS  Article  Google Scholar 

  9. Deser, C. & Wallace, J. M. Large-scale atmospheric circulation features of warm and cold episodes in the tropical Pacific. J. Clim. 3, 1254–1281 (1990)

    ADS  Article  Google Scholar 

  10. Cane, M. A. & Sarachik, E. S. Forced baroclinic ocean motions, Part II: The linear equatorial bounded case. J. Mar. Res. 35, 395–432 (1977)

    Google Scholar 

  11. Barber, R. T. & Chavez, F. P. Biological consequences of El Niño. Science 222, 1203–1210 (1983)

    ADS  CAS  Article  PubMed  Google Scholar 

  12. Trenberth, K. E., Fasullo, J. & Smith, L. Trends and variability in column integrated atmospheric water vapor. Clim. Dyn. 24, doi:10.1007/s00382–005–0017–4 (2005)

  13. Soden, B. J., Jackson, D. L., Ramaswamy, V., Schwarzkopf, M. D. & Huang, X. The radiative signature of upper tropospheric moistening. Science 310, 841–844, doi:10.1126/science.1115602 (2005)

    ADS  CAS  Article  PubMed  Google Scholar 

  14. Boer, G. J. Climate change and the regulation of the surface moisture and energy budgets. Clim. Dyn. 8, 225–239 (1993)

    Article  Google Scholar 

  15. Allen, M. R. & Ingram, W. J. Constraints on future changes in the hydrological cycle. Nature 419, 224–228 (2002)

    ADS  CAS  PubMed  Google Scholar 

  16. Delworth, T. L. et al. GFDL's CM2 global coupled climate models–Part 1: Formulation and simulation characteristics. J. Clim. 19(5), 643–674 (2006)

    ADS  Article  Google Scholar 

  17. Wittenberg, A. T., Rosati, A., Lau, N.-C. & Ploshay, J. J. GFDL's CM2 global coupled climate models–Part 3: Tropical Pacific climate and ENSO. J. Clim. 19(5), 698–722 (2006)

    ADS  Article  Google Scholar 

  18. Stouffer, R. et al. GFDL's CM2 global coupled climate models–Part 4: Idealized climate response. J. Clim. 19(5), 723–740 (2006)

    ADS  Article  Google Scholar 

  19. Clarke, A. J. & Lebedev, A. Long-term changes in equatorial Pacific trade winds. J. Clim. 9, 1020–1029 (1996)

    ADS  Article  Google Scholar 

  20. Jin, F.-F. An equatorial ocean recharge paradigm for ENSO. Part I: Conceptual model. J. Atmos. Sci. 54, 811–829 (1997)

    ADS  Article  Google Scholar 

  21. Fedorov, A. V. & Philander, S. G. Is El Niño changing? Science 288, 1997–2002 (2000)

    ADS  CAS  Article  PubMed  Google Scholar 

  22. Harrison, D. E. & Vecchi, G. A. El Niño and La Niña–Equatorial Pacific thermocline and sea surface temperature anomalies, 1986–98. Geophys. Res. Lett. 28, 1051–1054 (2001)

    ADS  Article  Google Scholar 

  23. Cardone, V. J., Greenwood, J. G. & Cane, M. A. On trends in historical marine wind data. J. Clim. 3, 113–127 (1990)

    ADS  Article  Google Scholar 

  24. Ramage, C. S. Can shipboard measurements reveal secular changes in tropical air-sea heat flux? J. Clim. Appl. Meteorol. 23, 187–193 (1984)

    ADS  Article  Google Scholar 

  25. Whysall, K. D. B., Cooper, N. S. & Bigg, G. R. Long-term changes in tropical Pacific surface wind field. Nature 327, 216–219 (1987)

    ADS  Article  Google Scholar 

  26. Harrison, D. E. Post World War II trends in tropical Pacific surface trades. J. Clim. 2, 1561–1563 (1989)

    ADS  Article  Google Scholar 

  27. Worley, S. J., Woodruff, S. D., Reynolds, R. W., Lubker, S. J. & Lot, N. ICOADS release 2.1 data and products. Int. J. Climatol. 25, 823–842 (2005)

    Article  Google Scholar 

  28. Basnett, T. & Parker, D. Development of the Global Mean Sea Level Pressure Data Set GMSLP2 (Climate Research Technical Note 79, Hadley Centre, Met Office, Exeter, UK, 1997)

    Google Scholar 

  29. Kaplan, A., Kushnir, Y. & Cane, M. A. Reduced space optimal interpolation of historical marine sea level pressure. J. Clim. 13, 2987–3002 (2000)

    ADS  Article  Google Scholar 

  30. Derber, J. & Rosati, A. A global oceanic data assimilation system. J. Phys. Oceanogr. 19, 1333–1347 (1989)

    ADS  Article  Google Scholar 

Download references

Acknowledgements

G.A.V. was supported by the Visiting Scientist Program at the NOAA/GFDL administered by UCAR. We are grateful to the model development teams at GFDL, and thank A. E. Johansson, M. P. Vecchi, T. Knutson, T. Delworth and J. Russell for comments and suggestions.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Gabriel A. Vecchi.

Ethics declarations

Competing interests

Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Supplementary information

Supplementary Methods

This file contains additional details of the methods used in this study. (DOC 44 kb)

Supplementary Figure 1

Evolution of ΔSLP from GFDL-CM2.1 historical integrations. (PDF 428 kb)

Supplementary Figure 2

Statistical significance limits of single-member Δ SLP trends of different lengths, estimated from the 2,000-year control GFDL-CM2.1 integration. (PDF 595 kb)

Supplementary Figure 3

Two-sided confidence intervals on zero Δ SLP trend from pre-Industrial IPCC-AR4 GCM control experiments. (PDF 359 kb)

Supplementary Figure 4

Linear trends of Δ SLP from IPCC-AR4 models. (PDF 276 kb)

Supplementary Figure 5

Modelled changes in equatorial Pacific oceanic currents. (PDF 688 kb)

Supplementary Figure 6

Evolution of equatorial Pacific thermocline depth and slope. (PDF 291 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Vecchi, G., Soden, B., Wittenberg, A. et al. Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing. Nature 441, 73–76 (2006). https://doi.org/10.1038/nature04744

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature04744

Further reading

Comments

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.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

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