Editorial Type:
Article
Article Type:
Research Article

A 10–15-Yr Modulation Cycle of ENSO Intensity

Fengpeng Sun Department of Earth System Science, University of California, Irvine, Irvine, California

Search for other papers by Fengpeng Sun in
Current site
Google Scholar
PubMed Close
and
Jin-Yi Yu Department of Earth System Science, University of California, Irvine, Irvine, California

Search for other papers by Jin-Yi Yu in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Apr 2009
DOI:
https://doi.org/10.1175/2008JCLI2285.1
Page(s):
1718–1735
Restricted access

Abstract

This study examines the slow modulation of El Niño–Southern Oscillation (ENSO) intensity and its underlying mechanism. A 10–15-yr ENSO intensity modulation cycle is identified from historical and paleoclimate data by calculating the envelope function of boreal winter Niño-3.4 and Niño-3 sea surface temperature (SST) indices. Composite analyses reveal interesting spatial asymmetries between El Niño and La Niña events within the modulation cycle. In the enhanced intensity periods of the cycle, El Niño is located in the eastern tropical Pacific and La Niña in the central tropical Pacific. The asymmetry is reversed in the weakened intensity periods: El Niño centers in the central Pacific and La Niña in the eastern Pacific. El Niño and La Niña centered in the eastern Pacific are accompanied with basin-scale surface wind and thermocline anomalies, whereas those centered in the central Pacific are accompanied with local wind and thermocline anomalies. The El Niño–La Niña asymmetries provide a possible mechanism for ENSO to exert a nonzero residual effect that could lead to slow changes in the Pacific mean state. The mean state changes are characterized by an SST dipole pattern between the eastern and central tropical Pacific, which appears as one leading EOF mode of tropical Pacific decadal variability. The Pacific Walker circulation migrates zonally in association with this decadal mode and also changes the mean surface wind and thermocline patterns along the equator. Although the causality has not been established, it is speculated that the mean state changes in turn favor the alternative spatial patterns of El Niño and La Niña that manifest as the reversed ENSO asymmetries. Using these findings, an ENSO–Pacific climate interaction mechanism is hypothesized to explain the decadal ENSO intensity modulation cycle.

* Current affiliation: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, California

Corresponding author address: Dr. Jin-Yi Yu, Department of Earth System Science, University of California, Irvine, Irvine, CA 92697-3100. Email: jyyu@uci.edu

Abstract

This study examines the slow modulation of El Niño–Southern Oscillation (ENSO) intensity and its underlying mechanism. A 10–15-yr ENSO intensity modulation cycle is identified from historical and paleoclimate data by calculating the envelope function of boreal winter Niño-3.4 and Niño-3 sea surface temperature (SST) indices. Composite analyses reveal interesting spatial asymmetries between El Niño and La Niña events within the modulation cycle. In the enhanced intensity periods of the cycle, El Niño is located in the eastern tropical Pacific and La Niña in the central tropical Pacific. The asymmetry is reversed in the weakened intensity periods: El Niño centers in the central Pacific and La Niña in the eastern Pacific. El Niño and La Niña centered in the eastern Pacific are accompanied with basin-scale surface wind and thermocline anomalies, whereas those centered in the central Pacific are accompanied with local wind and thermocline anomalies. The El Niño–La Niña asymmetries provide a possible mechanism for ENSO to exert a nonzero residual effect that could lead to slow changes in the Pacific mean state. The mean state changes are characterized by an SST dipole pattern between the eastern and central tropical Pacific, which appears as one leading EOF mode of tropical Pacific decadal variability. The Pacific Walker circulation migrates zonally in association with this decadal mode and also changes the mean surface wind and thermocline patterns along the equator. Although the causality has not been established, it is speculated that the mean state changes in turn favor the alternative spatial patterns of El Niño and La Niña that manifest as the reversed ENSO asymmetries. Using these findings, an ENSO–Pacific climate interaction mechanism is hypothesized to explain the decadal ENSO intensity modulation cycle.

* Current affiliation: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, California

Corresponding author address: Dr. Jin-Yi Yu, Department of Earth System Science, University of California, Irvine, Irvine, CA 92697-3100. Email: jyyu@uci.edu

Save
Cover Journal of Climate
Journal of Climate

  • Alexander, M. A., I. Bladé, M. Newman, J. R. Lanzante, N. C. Lau, and J. D. Scott, 2002: The atmospheric bridge: The influence of ENSO teleconnections on air–sea interaction over the global oceans. J. Climate, 15 , 2205–2231.

    • Search Google Scholar
    • Export Citation

  • An, S. I., and B. Wang, 2000: Interdecadal change of the structure of the ENSO mode and its impact on the ENSO frequency. J. Climate, 13 , 2044–2055.

    • Search Google Scholar
    • Export Citation

  • An, S. I., and F-F. Jin, 2004: Nonlinearity and asymmetry of ENSO. J. Climate, 17 , 2399–2412.

  • Barnett, T. P., D. W. Pierce, M. Latif, D. Dommenget, and R. Saravanan, 1999: Interdecadal interactions between the tropics and midlatitudes in the Pacific basin. Geophys. Res. Lett., 26 , 615–618.

    • Search Google Scholar
    • Export Citation

  • Battisti, D. S., and A. C. Hirst, 1989: Interannual variability in the tropical atmosphere–ocean system: Influences of the basic state, ocean geometry, and nonlinearity. J. Atmos. Sci., 46 , 1687–1712.

    • Search Google Scholar
    • Export Citation

  • Burgers, G., and D. B. Stephenson, 1999: The “normality” of El Niño. Geophys. Res. Lett., 26 , 1027–1030.

  • Carton, J. A., G. Chepurin, X. H. Cao, and B. Giese, 2000: A simple ocean data assimilation analysis of the global upper ocean 1950–95. Part I: Methodology. J. Phys. Oceanogr., 30 , 294–309.

    • Search Google Scholar
    • Export Citation

  • Deser, C., and J. M. Wallace, 1990: Large-scale atmospheric circulation features of warm and cold episodes in the tropical Pacific. J. Climate, 3 , 1254–1281.

    • Search Google Scholar
    • Export Citation

  • Deser, C., A. S. Phillips, and J. W. Hurrell, 2004: Pacific interdecadal climate variability: Linkages between the tropics and the North Pacific during boreal winter since 1900. J. Climate, 17 , 3109–3124.

    • Search Google Scholar
    • Export Citation

  • Dong, B-W., 2005: Asymmetry between El Niño and La Niña in a global coupled GCM with an eddy-permitting ocean resolution. J. Climate, 18 , 3084–3098.

    • Search Google Scholar
    • Export Citation

  • Eckert, C., and M. Latif, 1997: Predictability of a stochastically forced hybrid coupled model of El Niño. J. Climate, 10 , 1488–1504.

    • Search Google Scholar
    • Export Citation

  • Fedorov, A. V., and S. G. Philander, 2000: Is El Niño changing? Science, 288 , 1997–2002.

  • Gu, D., and S. G. H. Philander, 1995: Secular changes of annual and interannual variability in the tropics during the past century. J. Climate, 8 , 864–876.

    • Search Google Scholar
    • Export Citation

  • Gu, D., and S. G. H. Philander, 1997: Interdecadal climate fluctuations that depend on exchanges between the tropics and extratropics. Science, 275 , 805–807.

    • Search Google Scholar
    • Export Citation

  • Hoerling, M. P., A. Kumar, and M. Zhong, 1997: El Niño, La Niña, and the nonlinearity of their teleconnections. J. Climate, 10 , 1769–1786.

    • Search Google Scholar
    • Export Citation

  • Jin, F-F., and J. D. Neelin, 1993a: Modes of interannual tropical ocean–atmosphere interaction—A unified view. Part I: Numerical results. J. Atmos. Sci., 50 , 3477–3503.

    • Search Google Scholar
    • Export Citation

  • Jin, F-F., and J. D. Neelin, 1993b: Modes of interannual tropical ocean–atmosphere interaction—A unified view. Part III: Analytical results in fully coupled cases. J. Atmos. Sci., 50 , 3523–3540.

    • Search Google Scholar
    • Export Citation

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437–471.

  • Kao, H-Y., and J-Y. Yu, 2009: Contrasting eastern-Pacific and central-Pacific types of ENSO. J. Climate, 22 , 615–632.

  • Kirtman, B. P., and P. S. Schopf, 1998: Decadal variability in ENSO predictability and prediction. J. Climate, 11 , 2804–2822.

  • Knutson, T. R., S. Manabe, and D. Gu, 1997: Simulated ENSO in a global coupled ocean–atmosphere model: Multidecadal amplitude modulation and CO2 sensitivity. J. Climate, 10 , 131–161.

    • Search Google Scholar
    • Export Citation

  • Latif, M., A. Sterl, E. Majer-Reimer, and W. M. Junge, 1993: Climate variability in a coupled GCM. Part I: The tropical Pacific. J. Climate, 6 , 5–21.

    • Search Google Scholar
    • Export Citation

  • Levitus, S., J. Antonov, and T. Boyer, 2005: Warming of the world ocean, 1955–2003. Geophys. Res. Lett., 32 , L02604. doi:10.1029/2004GL021592.

    • Search Google Scholar
    • Export Citation

  • Mann, M. E., E. Gille, R. S. Bradley, M. K. Hughes, J. Overpeck, F. T. Keimig, and W. Gross, 2000: Global temperature patterns in past centuries: An interactive presentation. Earth Interactions, 4 .[Available online at http://EarthInteractions.org.].

    • Search Google Scholar
    • Export Citation

  • Mantua, N. J., S. R. Hare, Y. Zhang, J. M. Wallace, and R. C. Francis, 1997: A Pacific interdecadal climate oscillation with impacts on salmon production. Bull. Amer. Meteor. Soc., 78 , 1069–1079.

    • Search Google Scholar
    • Export Citation

  • Meehl, G. A., P. Gent, J. M. Arblaster, B. Otto-Bliesner, E. Brady, and A. Craig, 2001: Factors that affect amplitude of El Niño in global coupled climate models. Climate Dyn., 17 , 515–526.

    • Search Google Scholar
    • Export Citation

  • Monahan, A. H., 2001: Nonlinear principal component analysis: Tropical Indo–Pacific sea surface temperature and sea level pressure. J. Climate, 14 , 219–233.

    • Search Google Scholar
    • Export Citation

  • Nakamura, H., and J. M. Wallace, 1990: Observed changes in baroclinic wave activity during the life cycles of low-frequency circulation anomalies. J. Atmos. Sci., 47 , 1100–1116.

    • Search Google Scholar
    • Export Citation

  • Neelin, J. D., 1991: The slow sea surface temperature mode and the fast-wave limit: Analytic theory for tropical interannual oscillations and experiments in a hybrid coupled model. J. Atmos. Sci., 48 , 584–606.

    • Search Google Scholar
    • Export Citation

  • Neelin, J. D., and F-F. Jin, 1993: Modes of interannual tropical ocean–atmosphere interaction—A unified view. Part II: Analytical results in the weak-coupling limit. J. Atmos. Sci., 50 , 3504–3522.

    • Search Google Scholar
    • Export Citation

  • Newman, M., 2007: Interannual to decadal predictability of tropical and North Pacific sea surface temperatures. J. Climate, 20 , 2333–2356.

    • Search Google Scholar
    • Export Citation

  • Newman, M., G. P. Compo, and M. A. Alexander, 2003: ENSO-forced variability of the Pacific decadal oscillation. J. Climate, 16 , 3853–3857.

    • Search Google Scholar
    • Export Citation

  • Parks, T. W., and C. S. Burrus, 1987: Design of linear-phase finite impulse-response. Digital Filter Design, John Wiley & Sons, 33–110.

    • Search Google Scholar
    • Export Citation

  • Penland, C., and P. D. Sardeshmukh, 1995: The optimal growth of tropical sea surface temperature anomalies. J. Climate, 8 , 1999–2024.

  • Pierce, D. W., T. P. Barnett, and M. Latif, 2000: Connections between the Pacific Ocean tropics and midlatitudes on decadal timescales. J. Climate, 13 , 1173–1194.

    • Search Google Scholar
    • Export Citation

  • Power, S., T. Casey, C. Folland, A. Colman, and V. Mehta, 1999: Inter-decadal modulation of the impact of ENSO on Australia. Climate Dyn., 15 , 319–324.

    • Search Google Scholar
    • Export Citation

  • Rasmusson, E. M., and T. H. Carpenter, 1982: Variations in tropical sea surface temperature and surface wind fields associated with the Southern Oscillation/El Niño. Mon. Wea. Rev., 110 , 354–384.

    • Search Google Scholar
    • Export Citation

  • Rayner, N. A., D. E. Parker, E. B. Horton, C. K. Folland, L. V. Alexander, D. P. Rowell, E. C. Kent, and A. Kaplan, 2003: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res., 108 , 4407. doi:10.1029/2002JD002670.

    • Search Google Scholar
    • Export Citation

  • Rodgers, K. B., P. Friederichs, and M. Latif, 2004: Tropical Pacific decadal variability and its relation to decadal modulations of ENSO. J. Climate, 17 , 3761–3774.

    • Search Google Scholar
    • Export Citation

  • Schopf, P. S., and R. J. Burgman, 2006: A simple mechanism for ENSO residuals and asymmetry. J. Climate, 19 , 3167–3179.

  • Smith, T. M., and R. W. Reynolds, 2003: Extended reconstruction of global sea surface temperatures based on COADS data (1854–1997). J. Climate, 16 , 1495–1510.

    • Search Google Scholar
    • Export Citation

  • Smith, T. M., and R. W. Reynolds, 2004: Improved extended reconstruction of SST (1854–1997). J. Climate, 17 , 2466–2477.

  • Suarez, M. J., and P. S. Schopf, 1988: A delayed action oscillator for ENSO. J. Atmos. Sci., 45 , 3283–3287.

  • Sun, D-Z., 2007: The role of ENSO in regulating its background state. Nonlinear Dynamics in Geosciences, Springer, 604 pp.

  • 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

  • Tanaka, H. L., N. Ishizaki, and A. Kitoh, 2004: Trend and interannual variability of Walker, monsoon and Hadley circulations defined by velocity potential in the upper troposphere. Tellus, 56A , 250–269.

    • Search Google Scholar
    • Export Citation

  • Timmermann, A., 2003: Decadal ENSO amplitude modulations: A nonlinear paradigm. Global Planet. Change, 37 , 135–156.

  • Timmermann, A., and F-F. Jin, 2002: A nonlinear mechanism for decadal El Niño amplitude changes. Geophys. Res. Lett., 29 , 1003. doi:10.1029/2001GL013369.

    • Search Google Scholar
    • Export Citation

  • Torrence, C., and P. J. Webster, 1999: Interdecadal changes in the ENSO–monsoon system. J. Climate, 12 , 2679–2690.

  • Troup, A. J., 1965: The “southern oscillation.”. Quart. J. Roy. Meteor. Soc., 91 , 490–506.

  • Wang, B., and Y. Wang, 1996: Temporal structure of the Southern Oscillation as revealed by waveform and wavelet analysis. J. Climate, 9 , 1586–1598.

    • Search Google Scholar
    • Export Citation

  • Wang, C. Z., and R. H. Weisberg, 1998: Climate variability of the coupled tropical–extratropical ocean–atmosphere system. Geophys. Res. Lett., 25 , 3979–3982.

    • Search Google Scholar
    • Export Citation

  • Wilks, D. S., 1995: Statistical Methods in the Atmospheric Sciences. International Geophysics Series, Vol. 59, Academic Press, 464 pp.

  • Yeh, S-W., and B. P. Kirtman, 2004: Tropical Pacific decadal variability and ENSO amplitude modulation in a CGCM. J. Geophys. Res., 109 , C11009. doi:10.1029/2004JC002442.

    • Search Google Scholar
    • Export Citation

  • Yeh, S-W., and B. P. Kirtman, 2005: Pacific decadal variability and decadal ENSO amplitude modulation. Geophys. Res. Lett., 32 , L05703. doi:10.1029/2004GL021731.

    • Search Google Scholar
    • Export Citation

  • Zebiak, S. E., and M. A. Cane, 1987: A model for El Niño–Southern Oscillation. Mon. Wea. Rev., 115 , 2262–2278.

  • Zhang, X. B., J. Sheng, and A. Shabbar, 1998: Modes of interannual and interdecadal variability of Pacific SST. J. Climate, 11 , 2556–2569.

    • Search Google Scholar
    • Export Citation

  • Zhang, Y., J. M. Wallace, and D. S. Battisti, 1997: ENSO-like interdecadal variability: 1900–93. J. Climate, 10 , 1004–1020.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 646 320 15
PDF Downloads 334 108 16