Editorial Type:
Article
Article Type:
Research Article

Pacific Meridional Mode Does Not Induce Strong Positive SST Anomalies in the Central Equatorial Pacific

Ruikun Hu aCollege of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China
bState Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China

Search for other papers by Ruikun Hu in
Current site
Google Scholar
PubMed Close
https://orcid.org/0000-0001-7697-9495
,
Tao Lian bState Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
cSouthern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
dSchool of Oceanography, Shanghai Jiao Tong University, Shanghai, China

Search for other papers by Tao Lian in
Current site
Google Scholar
PubMed Close
,
Jie Feng bState Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
dSchool of Oceanography, Shanghai Jiao Tong University, Shanghai, China

Search for other papers by Jie Feng in
Current site
Google Scholar
PubMed Close
, and
Dake Chen bState Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
cSouthern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
dSchool of Oceanography, Shanghai Jiao Tong University, Shanghai, China

Search for other papers by Dake Chen in
Current site
Google Scholar
PubMed Close
Online Publication:
23 May 2023
Print Publication:
15 Jun 2023
DOI:
https://doi.org/10.1175/JCLI-D-22-0503.1
Page(s):
4113–4131
Restricted access

Abstract

The positive phase of the Pacific meridional mode (PMM) is closely related to the onset of El Niño. Previous studies have indicated that positive sea surface temperature anomalies (SSTAs) in the central equatorial Pacific (CEP) during the spring and summer of positive PMM years primarily originate from the northeastern tropical Pacific (NETP) via positive wind–evaporation–SST feedback. We review the evolution of PMM and find weak evidence to support such a linkage. Coupled model experiments show that the positive PMM-regressed SSTAs in the NETP only account for ∼24% of those in the CEP from winter to spring, illustrating the principle that correlation does not necessarily mean causality. The strongest positive PMM SSTAs in the NETP and CEP increase El Niño intensity by 1.07°C, whereas that in the NETP alone increase El Niño intensity by 0.69°C. When the composite SSTAs in the NETP during positive PMM years are used, however, the El Niño intensity is increased merely by 0.17°C. The change in the subsurface temperature in the equatorial Pacific is curtailed for the NETP SSTAs to trigger El Niño, while the wind–evaporation–SST feedback plays a less important role. Our results indicate that the impact of PMM on El Niño might be overestimated by ∼55%. Moreover, a comprehensive understanding about the role of the tropical North Pacific on El Niño can be obtained only when the impact from the western North Pacific is considered.

© 2023 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Tao Lian, liantao@sio.org.cn

Abstract

The positive phase of the Pacific meridional mode (PMM) is closely related to the onset of El Niño. Previous studies have indicated that positive sea surface temperature anomalies (SSTAs) in the central equatorial Pacific (CEP) during the spring and summer of positive PMM years primarily originate from the northeastern tropical Pacific (NETP) via positive wind–evaporation–SST feedback. We review the evolution of PMM and find weak evidence to support such a linkage. Coupled model experiments show that the positive PMM-regressed SSTAs in the NETP only account for ∼24% of those in the CEP from winter to spring, illustrating the principle that correlation does not necessarily mean causality. The strongest positive PMM SSTAs in the NETP and CEP increase El Niño intensity by 1.07°C, whereas that in the NETP alone increase El Niño intensity by 0.69°C. When the composite SSTAs in the NETP during positive PMM years are used, however, the El Niño intensity is increased merely by 0.17°C. The change in the subsurface temperature in the equatorial Pacific is curtailed for the NETP SSTAs to trigger El Niño, while the wind–evaporation–SST feedback plays a less important role. Our results indicate that the impact of PMM on El Niño might be overestimated by ∼55%. Moreover, a comprehensive understanding about the role of the tropical North Pacific on El Niño can be obtained only when the impact from the western North Pacific is considered.

© 2023 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Tao Lian, liantao@sio.org.cn
Save
Cover Journal of Climate
Journal of Climate

  • Alexander, M. A., D. J. Vimont, P. Chang, and J. D. Scott, 2010: The impact of extratropical atmospheric variability on ENSO: Testing the seasonal footprinting mechanism using coupled model experiments. J. Climate, 23, 2885–2901, https://doi.org/10.1175/2010JCLI3205.1.

    • Search Google Scholar
    • Export Citation

  • Amaya, D. J., 2019: The Pacific Meridional Mode and ENSO: A review. Curr. Climate Change Rep., 5, 296–307, https://doi.org/10.1007/s40641-019-00142-x.

    • Search Google Scholar
    • Export Citation

  • Amaya, D. J., Y. Kosaka, W. Zhou, Y. Zhang, S. P. Xie, and A. J. Miller, 2019: The North Pacific pacemaker effect on historical ENSO and its mechanisms. J. Climate, 32, 7643–7661, https://doi.org/10.1175/JCLI-D-19-0040.1.

    • Search Google Scholar
    • Export Citation

  • Anderson, B. T., and R. C. Perez, 2015: ENSO and non-ENSO induced charging and discharging of the equatorial Pacific. Climate Dyn., 45, 2309–2327, https://doi.org/10.1007/s00382-015-2472-x.

    • Search Google Scholar
    • Export Citation

  • Anderson, B. T., R. C. Perez, and A. Karspeck, 2013: Triggering of El Niño onset through trade wind-induced charging of the equatorial Pacific. Geophys. Res. Lett., 40, 1212–1216, https://doi.org/10.1002/grl.50200.

    • Search Google Scholar
    • Export Citation

  • Ashok, K., S. K. Behera, S. A. Rao, H. Weng, and T. Yamagata, 2007: El Niño Modoki and its possible teleconnection. J. Geophys. Res., 112, C11007, https://doi.org/10.1029/2006JC003798.

    • Search Google Scholar
    • Export Citation

  • Battisti, D. S., 1988: Dynamics and thermodynamics of a warming event in a coupled tropical atmosphere–ocean model. J. Atmos. Sci., 45, 2889–2919, https://doi.org/10.1175/1520-0469(1988)045<2889:DATOAW>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Battisti, D. S., and A. C. Hirst, 1989: Interannual variability in a tropical atmosphere-ocean model: Influence of the basic state, ocean geometry and nonlinearity. J. Atmos. Sci., 46, 1687–1712, https://doi.org/10.1175/1520-0469(1989)046<1687:IVIATA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Behringer, D. W., and Y. Xue, 2004: Evaluation of the global ocean data assimilation system at NCEP: The Pacific Ocean. Eighth Symp. on Integrated Observing and Assimilation Systems for Atmosphere, Oceans, and Land Surface, Seattle, WA, Amer. Meteor. Soc., 2.3, https://ams.confex.com/ams/84Annual/techprogram/paper_70720.htm.

  • Benjamini, Y., and Y. Hochberg, 1995: Controlling the false discovery rate: A practical and powerful approach to multiple testing. J. Roy. Stat. Soc., 57B, 289–300, https://doi.org/10.1111/j.2517-6161.1995.tb02031.x.

    • Search Google Scholar
    • Export Citation

  • Bjerknes, J., 1969: Atmospheric teleconnections from the equatorial Pacific 1. Mon. Wea. Rev., 97, 163–172, https://doi.org/10.1175/1520-0493(1969)097<0163:ATFTEP>2.3.CO;2.

    • Search Google Scholar
    • Export Citation

  • Bond, N. A., J. E. Overland, M. Spillane, and P. Stabeno, 2003: Recent shifts in the state of the North Pacific. Geophys. Res. Lett., 30, 2–5, https://doi.org/10.1029/2003GL018597.

    • Search Google Scholar
    • Export Citation

  • Capotondi, A., and Coauthors, 2015: Understanding ENSO diversity. Bull. Amer. Meteor. Soc., 96, 921–938, https://doi.org/10.1175/BAMS-D-13-00117.1.

    • Search Google Scholar
    • Export Citation

  • Chakravorty, S., R. C. Perez, B. T. Anderson, S. M. Larson, B. S. Giese, and V. Pivotti, 2021: Ocean dynamics are key to extratropical forcing of El Niño. J. Climate, 34, 8739–8753, https://doi.org/10.1175/JCLI-D-20-0933.1.

    • Search Google Scholar
    • Export Citation

  • Chang, P., L. Zhang, R. Saravanan, D. J. Vimont, J. C. H. Chiang, L. Ji, H. Seidel, and M. K. Tippett, 2007: Pacific meridional mode and El Niño–Southern Oscillation. Geophys. Res. Lett., 34, L16608, https://doi.org/10.1029/2007GL030302.

    • Search Google Scholar
    • Export Citation

  • Chen, D., and Coauthors, 2015: Strong influence of westerly wind bursts on El Niño diversity. Nat. Geosci., 8, 339–345, https://doi.org/10.1038/ngeo2399.

    • Search Google Scholar
    • Export Citation

  • Chiang, J. C. H., and D. J. Vimont, 2004: Analogous Pacific and Atlantic meridional modes of tropical atmosphere–ocean variability. J. Climate, 17, 4143–4158, https://doi.org/10.1175/JCLI4953.1.

    • Search Google Scholar
    • Export Citation

  • Ding, R., J. Li, Y. H. Tseng, and C. Ruan, 2015a: Influence of the North Pacific Victoria mode on the Pacific ITCZ summer precipitation. J. Geophys. Res. Atmos., 120, 964–979, https://doi.org/10.1002/2014JD022364.

    • Search Google Scholar
    • Export Citation

  • Ding, R., J. Li, Y. H. Tseng, C. Sun, and Y. Guo, 2015b: The Victoria mode in the North Pacific linking extratropical sea level pressure variations to ENSO. J. Geophys. Res. Atmos., 120, 27–45, https://doi.org/10.1002/2014JD022221.

    • Search Google Scholar
    • Export Citation

  • Fan, H., B. Huang, S. Yang, and W. Dong, 2021: Influence of the Pacific Meridional Mode on ENSO evolution and predictability: Asymmetric modulation and ocean preconditioning. J. Climate, 34, 1881–1901, https://doi.org/10.1175/JCLI-D-20-0109.1.

    • Search Google Scholar
    • Export Citation

  • Fu, C., H. F. Diaz, and J. O. Fletcher, 1986: Characteristics of the response of sea surface temperature in the central Pacific associated with warm episodes of the Southern Oscillation. Mon. Wea. Rev., 114, 1716–1738, https://doi.org/10.1175/1520-0493(1986)114<1716:COTROS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Gill, A. E., 1980: Some simple solutions for heat-induced tropical circulation. Quart. J. Roy. Meteor. Soc., 106, 447–462, https://doi.org/10.1002/qj.49710644905.

    • Search Google Scholar
    • Export Citation

  • Hersbach, H., and Coauthors, 2019: ERA5 monthly averaged data on single levels from 1979 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS), accessed March 2021, https://www.eea.europa.eu/data-and-maps/data/external/era5-monthly-averaged-data-on.

  • Ji, K., Y. Tseng, R. Ding, J. Mao, and L. Feng, 2022: Relative contributions to ENSO of the seasonal footprinting and trade wind charging mechanisms associated with the Victoria mode. Climate Dyn., 60, 47–63, https://doi.org/10.1007/s00382-022-06300-6.

    • Search Google Scholar
    • Export Citation

  • Jin, F. F., 1997: An equatorial ocean recharge paradigm for ENSO. Part I: Conceptual model. J. Atmos. Sci., 54, 811–829, https://doi.org/10.1175/1520-0469(1997)054<0811:AEORPF>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Kosaka, Y., and S. P. Xie, 2013: Recent global-warming hiatus tied to equatorial Pacific surface cooling. Nature, 501, 403–407, https://doi.org/10.1038/nature12534.

    • Search Google Scholar
    • Export Citation

  • Kug, J.-S., F. F. Jin, and S. I. An, 2009: Two types of El Niño events: Cold tongue El Niño and warm pool El Niño. J. Climate, 22, 1499–1515, https://doi.org/10.1175/2008JCLI2624.1.

    • Search Google Scholar
    • Export Citation

  • Kug, J.-S., J. Vialard, Y.-G. Ham, J.-Y. Yu, and M. Lengaigne, 2021: Chapter 11: ENSO remote forcing: Influence of climate variability outside the Tropical Pacific. El Niño Southern Oscillation in a Changing Climate, Geophys. Monogr., Vol. 253, Amer. Geophys. Union, 247–265, https://doi.org/10.1002/9781119548164.ch11.

  • Large, W. G., G. Danabasoglu, S. C. Doney, and J. C. Mcwilliams, 1997: Sensitivity to surface forcing and boundary layer mixing in a global ocean model: Annual-mean climatology. J. Phys. Oceanogr., 27, 2418–2447, https://doi.org/10.1175/1520-0485(1997)027<2418:STSFAB>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Larkin, N. K., and D. E. Harrison, 2005: On the definition of El Niño and associated seasonal average U.S. weather anomalies. Geophys. Res. Lett., 32, L13705, https://doi.org/10.1029/2005GL022738.

    • Search Google Scholar
    • Export Citation

  • Li, X., S. P. Xie, S. T. Gille, and C. Yoo, 2016: Atlantic-induced pan-tropical climate change over the past three decades. Nat. Climate Change, 6, 275–279, https://doi.org/10.1038/nclimate2840.

    • Search Google Scholar
    • Export Citation

  • Lin, C.-Y., J.-Y. Yu, and H.-H. Hsu, 2015: CMIP5 model simulations of the Pacific meridional mode and its connection to the two types of ENSO. Int. J. Climatol., 35, 2352–2358, https://doi.org/10.1002/joc.4130.

    • Search Google Scholar
    • Export Citation

  • Linkin, M. E., and S. Nigam, 2008: The North Pacific Oscillation–west Pacific teleconnection pattern: Mature-phase structure and winter impacts. J. Climate, 21, 1979–1997, https://doi.org/10.1175/2007JCLI2048.1.

    • Search Google Scholar
    • Export Citation

  • Lübbecke, J. F., and M. J. McPhaden, 2014: Assessing the twenty-first-century shift in ENSO variability in terms of the Bjerknes stability index. J. Climate, 27, 2577–2587, https://doi.org/10.1175/JCLI-D-13-00438.1.

    • Search Google Scholar
    • Export Citation

  • McPhaden, M. J., T. Lee, and D. McClurg, 2011: El Niño and its relationship to changing background conditions in the tropical Pacific Ocean. Geophys. Res. Lett., 38, 2–5, https://doi.org/10.1029/2011GL048275.

    • Search Google Scholar
    • Export Citation

  • Pegion, K., C. M. Selman, S. Larson, J. C. Furtado, and E. J. Becker, 2020: The impact of the extratropics on ENSO diversity and predictability. Climate Dyn., 54, 4469–4484, https://doi.org/10.1007/s00382-020-05232-3.

    • Search Google Scholar
    • Export Citation

  • Pyper, B. J., and R. M. Peterman, 1998: Comparison of methods to account for autocorrelation in correlation analyses of fish data. Can. J. Fish. Aquat. Sci., 55, 2127–2140, https://doi.org/10.1139/f98-104.

    • Search Google Scholar
    • Export Citation

  • Ramesh, N., and R. Murtugudde, 2013: All flavours of El Niño have similar early subsurface origins. Nat. Climate Change, 3, 42–46, https://doi.org/10.1038/nclimate1600.

    • 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, https://doi.org/10.1029/2002JD002670.

    • Search Google Scholar
    • Export Citation

  • Rogers, J. C., 1981: The North Pacific Oscillation. J. Climatol., 1, 39–57, https://doi.org/10.1002/joc.3370010106.

  • Smith, R., and Coauthors, 2010: The Parallel Ocean Program (POP) reference manual ocean component of the Community Climate System Model (CCSM) and Community Earth System Model (CESM). Los Alamos National Laboratory LAUR-10-01853, 141 pp., https://www2.cesm.ucar.edu/models/cesm1.0/pop2/doc/sci/POPRefManual.pdf.

  • Suarez, M. J., and P. S. Schopf, 1988: A delayed action oscillator for ENSO. J. Atmos. Sci., 45, 3283–3287, https://doi.org/10.1175/1520-0469(1988)045<3283:ADAOFE>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Takahashi, K., A. Montecinos, K. Goubanova, and B. Dewitte, 2011: ENSO regimes: Reinterpreting the canonical and Modoki El Niño. Geophys. Res. Lett., 38, L10704, https://doi.org/10.1029/2011GL047364.

    • Search Google Scholar
    • Export Citation

  • Thomas, E. E., and D. J. Vimont, 2016: Modeling the mechanisms of linear and nonlinear ENSO responses to the Pacific meridional mode. J. Climate, 29, 8745–8761, https://doi.org/10.1175/JCLI-D-16-0090.1.

    • Search Google Scholar
    • Export Citation

  • Tseng, Y. H., R. Ding, S. Zhao, Y. C. Kuo, and Y. C. Liang, 2020: Could the North Pacific Oscillation be modified by the initiation of the East Asian winter monsoon? J. Climate, 33, 2389–2406, https://doi.org/10.1175/JCLI-D-19-0112.1.

    • Search Google Scholar
    • Export Citation

  • Vertenstein, M., T. Craig, A. Middleton, D. Feddema, and C. Fischer, 2012: CESM1.0.4 user’s guide. National Center of Atmosphere Research, 154 pp., https://www.cesm.ucar.edu/models/cesm1.0/cesm/.

  • Vimont, D. J., D. S. Battisti, and A. C. Hirst, 2001: Footprinting: A seasonal connection between the tropics and mid-latitudes. Geophys. Res. Lett., 28, 3923–3926, https://doi.org/10.1029/2001GL013435.

    • Search Google Scholar
    • Export Citation

  • Vimont, D. J., J. M. Wallace, and D. S. Battisti, 2003a: The seasonal footprinting mechanism in the Pacific: Implications for ENSO. J. Climate, 16, 2668–2675, https://doi.org/10.1175/1520-0442(2003)016<2668:TSFMIT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Vimont, D. J., D. S. Battisti, and A. C. Hirst, 2003b: The seasonal footprinting mechanism in the CSIRO general circulation models. J. Climate, 16, 2653–2667, https://doi.org/10.1175/1520-0442(2003)016<2653:TSFMIT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Vimont, D. J., M. Alexander, and A. Fontaine, 2009: Midlatitude excitation of tropical variability in the Pacific: The role of thermodynamic coupling and seasonality. J. Climate, 22, 518–534, https://doi.org/10.1175/2008JCLI2220.1.

    • Search Google Scholar
    • Export Citation

  • Wang, S. Y., M. L’Heureux, and H. H. Chia, 2012: ENSO prediction one year in advance using western North Pacific sea surface temperatures. Geophys. Res. Lett., 39, 2–7, https://doi.org/10.1029/2012GL050909.

    • Search Google Scholar
    • Export Citation

  • Wang, S. Y., M. L’heureux, and J. H. Yoon, 2013: Are greenhouse gases changing ENSO precursors in the western North Pacific? J. Climate, 26, 6309–6322, https://doi.org/10.1175/JCLI-D-12-00360.1.

    • Search Google Scholar
    • Export Citation

  • Wang, X., C. Guan, R. X. Huang, W. Tan, and L. Wang, 2019: The roles of tropical and subtropical wind stress anomalies in the El Niño Modoki onset. Climate Dyn., 52, 6585–6597, https://doi.org/10.1007/s00382-018-4534-3.

    • Search Google Scholar
    • Export Citation

  • Wilks, D. S., 2006: On “field significance” and the false discovery rate. J. Appl. Meteor. Climatol., 45, 1181–1189, https://doi.org/10.1175/JAM2404.1.

    • Search Google Scholar
    • Export Citation

  • Wilks, D. S., 2016: “The stippling shows statistically significant grid points”: How research results are routinely overstated and overinterpreted, and what to do about it. Bull. Amer. Meteor. Soc., 97, 2263–2273, https://doi.org/10.1175/BAMS-D-15-00267.1.

    • Search Google Scholar
    • Export Citation

  • Xie, R., and F. F. Jin, 2018: Two leading ENSO modes and El Niño types in the Zebiak–Cane model. J. Climate, 31, 1943–1962, https://doi.org/10.1175/JCLI-D-17-0469.1.

    • Search Google Scholar
    • Export Citation

  • Xie, S.-P., and S. G. H. Philander, 1994: A coupled ocean-atmosphere model of relevance to the ITCZ in the eastern Pacific. Tellus, 46A, 340–350, https://doi.org/10.3402/tellusa.v46i4.15484.

    • Search Google Scholar
    • Export Citation

  • Yeh, S. W., and Coauthors, 2018: ENSO atmospheric teleconnections and their response to greenhouse gas forcing. Rev. Geophys., 56, 185–206, https://doi.org/10.1002/2017RG000568.

    • Search Google Scholar
    • Export Citation

  • You, Y., and J. C. Furtado, 2017: The role of South Pacific atmospheric variability in the development of different types of ENSO. Geophys. Res. Lett., 44, 7438–7446, https://doi.org/10.1002/2017GL073475.

    • Search Google Scholar
    • Export Citation

  • Yu, J. Y., and S. T. Kim, 2010: Identification of central-Pacific and eastern-Pacific types of ENSO in CMIP3 models. Geophys. Res. Lett., 37, L15705, https://doi.org/10.1029/2010GL044082.

    • Search Google Scholar
    • Export Citation

  • Zhao, J., J. S. Kug, J. H. Park, and S. I. An, 2020: Diversity of North Pacific meridional mode and its distinct impacts on El Niño–Southern Oscillation. Geophys. Res. Lett., 47, e2020GL088993, https://doi.org/10.1029/2020GL088993.

    • Search Google Scholar
    • Export Citation

  • Zheng, Y., W. Chen, S. Chen, S. Yao, and C. Cheng, 2021: Asymmetric impact of the boreal spring Pacific meridional mode on the following winter El Niño–Southern Oscillation. Int. J. Climatol., 41, 3523–3538, https://doi.org/10.1002/joc.7033.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 637 637 24
Full Text Views 291 291 10
PDF Downloads 395 395 11