Letter | Published:

All flavours of El Niño have similar early subsurface origins

Nature Climate Change volume 3, pages 4246 (2013) | Download Citation

Abstract

The El Niño/Southern Oscillation phenomenon, characterized by anomalous sea surface temperatures and winds in the tropical Pacific, affects climate across the globe1. El Niños occur every 2–7 years, whereas the El Niño/Southern Oscillation itself varies on decadal timescales in frequency and amplitude, with a different spatial pattern of surface anomalies2 each time the tropical Pacific undergoes a regime shift. Recent work has shown that Bjerknes feedback3,4 (coupling of the atmosphere and the ocean through changes in equatorial winds driven by changes in sea surface temperature owing to suppression of equatorial upwelling in the east Pacific) is not necessary5 for the development of an El Niño. Thus it is unclear what remains constant through regimes and is crucial for producing the anomalies recognized as El Niño. Here we show that the subsurface process of discharging warm waters always begins in the boreal summer/autumn of the year before the event (up to 18 months before the peak) independent of regimes, identifying the discharge process as fundamental to the El Niño onset. It is therefore imperative that models capture this process accurately to further our theoretical understanding, improve forecasts and predict how the El Niño/Southern Oscillation may respond to climate change.

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References

  1. 1.

    et al. The atmospheric bridge: The influence of ENSO teleconnections on air–sea interaction over the global oceans. J. Clim. 15, 2205–2228 (2002).

  2. 2.

    & Is El Niño changing? Science 288, 1997–2002 (2000).

  3. 3.

    Atmospheric teleconnections from the equatorial Pacific. Mon. Weath. Rev. 97, 163–172 (1969).

  4. 4.

    A possible response of the atmospheric Hadley circulation to equatorial anomalies of ocean temperature. Tellus 18, 820–829 (1966).

  5. 5.

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

  6. 6.

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

  7. 7.

    An equatorial ocean recharge paradigm for ENSO. Part II: A stripped-down coupled model. J. Atmos. Sci. 54, 830–847 (1997).

  8. 8.

    Water displacements in the Pacific and the genesis of El Niño cycles. J. Geophys. Res. 90, 7129–7132 (1985).

  9. 9.

    & Is El Niño sporadic or cyclic? Annu. Rev. Earth Planet. Sci. 31, 579–594 (2003).

  10. 10.

    Is ENSO a cycle or a series of events? Geophys. Res. Lett. 29, 2125–2128 (2002).

  11. 11.

    & Observations of warm water volume changes in the equatorial pacific and their relationship to El Niño and La Niña. J. Clim. 13, 3551–3559 (2001).

  12. 12.

    & Variations in sea surface temperature and surface wind fields associated with the Southern Oscillation/El Niño. Mon. Weath. Rev. 110, 354–384 (1982).

  13. 13.

    & A mechanism for decadal changes of ENSO behavior: Roles of background wind changes. Clim. Dynam. 18, 475–486 (2002).

  14. 14.

    & Contrasting Eastern-Pacific and Central-Pacific types of ENSO. J. Clim. 22, 615–632 (2009).

  15. 15.

    & Increasing intensity of El Niño in the central-equatorial Pacific. Geophys. Res. Lett. 37, L14603 (2010).

  16. 16.

    The annual cycle and the predictability of the tropical coupled ocean–atmosphere system. Meteorol. Atmos. Phys. 56, 33–55 (1994).

  17. 17.

    et al. Pacific meridional mode and El Niño—Southern Oscillation. Geophys. Res. Lett. 34, L16608 (2007).

  18. 18.

    , & The seasonal footprinting mechanism in the Pacific: Implications for ENSO. J. Clim. 16, 2668–2675 (2003).

  19. 19.

    et al. Triggering of El Niño by westerly wind events in a coupled general circulation model. Clim. Dynam. 23, 601–620 (2004).

  20. 20.

    & The annual cycle of persistence in the El Niño-Southern Oscillation. Q. J. R. Meteorol. Soc. 125, 1985–2004 (1994).

  21. 21.

    & Has the climate recently shifted? Geophys. Res. Lett. 36, L06711 (2009).

  22. 22.

    et al. El Niño in a changing climate. Nature 461, 511–514 (2009).

  23. 23.

    , & Contrasting the flavours of El Niño-Southern Oscillation using sea surface salinity observations. J. Geophys. Res. 116, C06016 (2011).

  24. 24.

    The definition of El Niño. Bull. Am. Meteorol. Soc. 78, 2771–2777 (1997).

  25. 25.

    et al. The impact of global warming on the tropical Pacific Ocean and El Niño. Nature Geosci. 3, 391–397 (2010).

  26. 26.

    & The 1990–1995 El Niño-Southern Oscillation event: Longest on record. Geophys. Res. Lett. 23, 57–60 (1996).

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Acknowledgements

This work was carried out at the Divecha Centre for Climate Change, Indian Institute of Science, Bangalore—560012, India, enabled by grants from the same. The authors would like to thank J. Beauchamp for providing the SODA, Global Ocean Data Assimilation System and Global High-Resolution SST data. N.R. would like to thank S. R. Parampil for assistance with the Ferret software.

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Affiliations

  1. Divecha Centre for Climate Change, Indian Institute of Science, Bangalore 560012, India

    • Nandini Ramesh
  2. Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20742, USA

    • Raghu Murtugudde

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Contributions

Analysis of the data, production of the figures and writing of the final manuscript was carried out by N.R. The project was supervised and directed by R.M. who interpreted results and also edited the final manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Nandini Ramesh.

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DOI

https://doi.org/10.1038/nclimate1600

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