• An, S.-I., and H. Bong, 2016: Inter-decadal change in El Niño-Southern Oscillation examined with Bjerknes stability index analysis. Climate Dyn., 47, 967979, https://doi.org/10.1007/s00382-015-2883-8.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • An, S.-I., J.-W. Kim, S.-H. Im, B.-M. Kim, and J.-H. Park, 2012: Recent and future sea surface temperature trends in tropical Pacific warm pool and cold tongue regions. Climate Dyn., 39, 13731383, https://doi.org/10.1007/s00382-011-1129-7.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Azad, S., and M. Rajeevan, 2016: Possible shift in the ENSO-Indian monsoon rainfall relationship under future global warming. Sci. Rep., 6, 20 145, https://doi.org/10.1038/srep20145.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Banzon, V., T. M. Smith, M. Steele, B. Huang, and H.-M. Zhang, 2020: Improved estimation of proxy sea surface temperature in the arctic. J. Atmos. Oceanic Technol., 37, 341349, https://doi.org/10.1175/JTECH-D-19-0177.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bamston, A. G., M. Chelliah, and S. B. Goldenberg, 1997: Documentation of a highly ENSO-related SST region in the equatorial Pacific. Atmos.–Ocean, 35, 367383, https://doi.org/10.1080/07055900.1997.9649597.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Barnston, A. G., M. K. Tippett, M. Ranganathan, and M. L. L’Heureux, 2019: Deterministic skill of ENSO predictions from the North American Multimodel Ensemble. Climate Dyn., 53, 72157234, https://doi.org/10.1007/s00382-017-3603-3.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bloomfield, P., 2004: Fourier Analysis of Time Series: An Introduction. John Wiley & Sons, 288 pp.

  • Buckley, M. W., and J. Marshall, 2016: Observations, inferences, and mechanisms of the Atlantic Meridional Overturning Circulation: A review. Rev. Geophys., 54, 563, https://doi.org/10.1002/2015RG000493.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Burls, N. J., A. V. Fedorov, D. M. Sigman, S. L. Jaccard, R. Tiedemann, and G. H. Haug, 2017: Active Pacific Meridional Overturning Circulation (PMOC) during the warm Pliocene. Sci. Adv., 3, e1700156, https://doi.org/10.1126/sciadv.1700156.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Caesar, L., G. McCarthy, G. Thornalley, N. Cahill, and S. Rahmstorf, 2021: Current Atlantic Meridional Overturning Circulation weakest in last millennium. Nat. Geosci., 14, 118120, https://doi.org/10.1038/s41561-021-00699-z.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cai, W., and Coauthors, 2014: Increasing frequency of extreme El Niño events due to greenhouse warming. Nat. Climate Change, 4, 111116, https://doi.org/10.1038/nclimate2100.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Capotondi, A., and P. D. Sardeshmukh, 2017: Is El Niño really changing? Geophys. Res. Lett., 44, 85488556, https://doi.org/10.1002/2017GL074515.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Capotondi, A., M. A. Alexander, C. Deser, and M. J. McPhaden, 2005: Anatomy and decadal evolution of the Pacific subtropical–tropical cells (STCs). J. Climate, 18, 37393758, https://doi.org/10.1175/JCLI3496.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Capotondi, A., and Coauthors, 2015: Understanding ENSO diversity. Bull. Amer. Meteor. Soc., 96, 921938, https://doi.org/10.1175/BAMS-D-13-00117.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Capotondi, A., C. Deser, A. Phillips, Y. Okumura, and S. Larson, 2020: ENSO and Pacific decadal variability in the Community Earth System Model version 2. J. Adv. Model. Earth Syst., 12, e2019MS002022, https://doi.org/10.1029/2019MS002022.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, H.-C., and F.-F. Jin, 2020: Fundamental behavior of ENSO phase locking. J. Climate, 33, 19531968, https://doi.org/10.1175/JCLI-D-19-0264.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, H.-C., C.-H. Sui, Y.-H. Tseng, and B. Huang, 2015: An analysis of the linkage of Pacific subtropical cells with the recharge–discharge processes in ENSO evolution. J. Climate, 28, 37863805, https://doi.org/10.1175/JCLI-D-14-00134.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Choi, K.-Y., G. A. Vecchi, and A. T. Wittenberg, 2015: Nonlinear zonal wind response to ENSO in the CMIP5 models: Roles of the zonal and meridional shift of the ITCZ/SPCZ and the simulated climatological precipitation. J. Climate, 28, 85568573, https://doi.org/10.1175/JCLI-D-15-0211.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Clark, P. U., N. G. Pisias, T. F. Stocker, and A. J. Weaver, 2002: The role of the thermohaline circulation in abrupt climate change. Nature, 415, 863869, https://doi.org/10.1038/415863a.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dahl, K. A., A. J. Broccoli, and R. J. Stouffer, 2005: Assessing the role of North Atlantic freshwater forcing in millennial scale climate variability: A tropical Atlantic perspective. Climate Dyn., 24, 325346, https://doi.org/10.1007/s00382-004-0499-5.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Danabasoglu, G., S. C. Bates, B. P. Briegleb, S. R. Jayne, M. Jochum, W. G. Large, S. Peacock, and S. G. Yeager, 2012: The CCSM4 ocean component. J. Climate, 25, 13611389, https://doi.org/10.1175/JCLI-D-11-00091.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dickson, R. R., and J. Brown, 1994: The production of North Atlantic Deep Water: Sources, rates, and pathways. J. Geophys. Res., 99, 12 31912 341, https://doi.org/10.1029/94JC00530.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dong, B.-W., and R. T. Sutton, 2002: Adjustment of the coupled ocean–atmosphere system to a sudden change in the thermohaline circulation. Geophys. Res. Lett., 29, 1728, https://doi.org/10.1029/2002GL015229.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dong, B.-W., and R. T. Sutton, 2007: Enhancement of ENSO variability by a weakened Atlantic thermohaline circulation in a coupled GCM. J. Climate, 20, 49204939, https://doi.org/10.1175/JCLI4284.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Drijfhout, S., G. J. Van Oldenborgh, and A. Cimatoribus, 2012: Is a decline of AMOC causing the warming hole above the North Atlantic in observed and modeled warming patterns? J. Climate, 25, 83738379, https://doi.org/10.1175/JCLI-D-12-00490.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Farge, M., 1992: Wavelet transforms and their applications to turbulence. Annu. Rev. Fluid Mech., 24, 395458, https://doi.org/10.1146/annurev.fl.24.010192.002143.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Fedorov, A. V., and S. G. Philander, 2001: A stability analysis of tropical ocean–atmosphere interactions: Bridging measurements and theory for El Niño. J. Climate, 14, 30863101, https://doi.org/10.1175/1520-0442(2001)014<3086:ASAOTO>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Feng, J., D. Hu, F. Jin, F. Jia, Q. Wang, and S. Guan, 2018: The different relationship of Pacific interior subtropical cells and two types of ENSO. J. Oceanogr., 74, 523539, https://doi.org/10.1007/s10872-018-0478-9.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ferreira, D., and Coauthors, 2018: Atlantic-Pacific asymmetry in deep water formation. Annu. Rev. Earth Planet. Sci., 46, 327352, https://doi.org/10.1146/annurev-earth-082517-010045.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Guilyardi, E., 2006: El Niño–mean state–seasonal cycle interactions in a multi-model ensemble. Climate Dyn., 26, 329348, https://doi.org/10.1007/s00382-005-0084-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hu, A., G. A. Meehl, and W. Han, 2007: Role of the Bering Strait in the thermohaline circulation and abrupt climate change. Geophys. Res. Lett., 34, L05704, https://doi.org/10.1029/2006GL028906.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hu, A., and Coauthors, 2010: Influence of Bering Strait flow and North Atlantic circulation on glacial sea-level changes. Nat. Geosci., 3, 118121, https://doi.org/10.1038/ngeo729.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hu, A., G. A. Meehl, W. Han, and J. Yin, 2011: Effect of the potential melting of the Greenland Ice Sheet on the Meridional Overturning Circulation and global climate in the future. Deep-Sea Res. II, 58, 19141926, https://doi.org/10.1016/j.dsr2.2010.10.069.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hu, A., G. A. Meehl, W. Han, A. Abe-Ouchi, C. Morrill, Y. Okazaki, and M. O. Chikamoto, 2012a: The Pacific-Atlantic seesaw and the Bering Strait. Geophys. Res. Lett., 39, L03702, https://doi.org/10.1029/2011GL050567.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hu, A., and Coauthors, 2012b: Role of the Bering Strait on the hysteresis of the ocean conveyor belt circulation and glacial climate stability. Proc. Natl. Acad. Sci. USA, 109, 64176422, https://doi.org/10.1073/pnas.1116014109.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hu, A., G. A. Meehl, W. Han, B. Otto-Bliestner, A. Abe-Ouchi, and N. Rosenbloom, 2015: Effects of the Bering Strait closure on AMOC and global climate under different background climates. Prog. Oceanogr., 132, 174196, https://doi.org/10.1016/j.pocean.2014.02.004.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hu, A., G. A. Meehl, N. Rosenbloom, M. J. Molina, and W. G. Strand, 2021: The influence of variability in meridional overturning on global ocean circulation. J. Climate, 34, 76977716, https://doi.org/10.1175/JCLI-D-21-0119.1.

    • Search Google Scholar
    • Export Citation
  • Hunke, E. C., W. H. Lipscomb, A. Turner, N. Jeffery, and S. Elliott, 2008: CICE: The Los Alamos Sea ice model documentation and software user’s manual version 4.0 LA-CC-06-012. Tech. Rep. LA-CC-06-012, 500 pp.

  • Hurrell, J. W., and Coauthors, 2013: The Community Earth System Model: A framework for collaborative research. Bull. Amer. Meteor. Soc., 94, 13391360, https://doi.org/10.1175/BAMS-D-12-00121.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hwang, Y.-T., H.-Y. Tseng, K.-C. Li, S. M. Kang, Y.-J. Chen, and J. C. Chiang, 2021: Relative roles of energy and momentum fluxes in the tropical response to extratropical thermal forcing. J. Climate, 34, 37713786, https://doi.org/10.1175/JCLI-D-20-0151.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jackson, L., R. Kahana, T. Graham, M. Ringer, T. Woollings, J. Mecking, and R. Wood, 2015: Global and European climate impacts of a slowdown of the AMOC in a high resolution GCM. Climate Dyn., 45, 32993316, https://doi.org/10.1007/s00382-015-2540-2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jin, F.-F., 1997a: An equatorial ocean recharge paradigm for ENSO. Part I: Conceptual model. J. Atmos. Sci., 54, 811829, https://doi.org/10.1175/1520-0469(1997)054<0811:AEORPF>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jin, F.-F., 1997b: An equatorial ocean recharge paradigm for ENSO. Part II: A stripped-down coupled model. J. Atmos. Sci., 54, 830847, https://doi.org/10.1175/1520-0469(1997)054<0830:AEORPF>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kang, S. M., Y. Shin, and S.-P. Xie, 2018: Extratropical forcing and tropical rainfall distribution: Energetics framework and ocean Ekman advection. npj Climate Atmos. Sci., 1, 20172, https://doi.org/10.1038/s41612-017-0004-6.

    • Search Google Scholar
    • Export Citation
  • Kessler, W. S., 1990: Observations of long Rossby waves in the northern tropical Pacific. J. Geophys. Res., 95, 51835217, https://doi.org/10.1029/JC095iC04p05183.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kim, D., S.-K. Lee, H. Lopez, and M. Goes, 2020: Pacific mean-state control of Atlantic multidecadal oscillation–El Niño relationship. J. Climate, 33, 42734291, https://doi.org/10.1175/JCLI-D-19-0398.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kousky, V., and R. Higgins, 2007: An alert classification system for monitoring and assessing the ENSO cycle. Wea. Forecasting, 22, 353371, https://doi.org/10.1175/WAF987.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lau, N.-C., and M. J. Nath, 2003: Atmosphere–ocean variations in the Indo-Pacific sector during ENSO episodes. J. Climate, 16, 320, https://doi.org/10.1175/1520-0442(2003)016<0003:AOVITI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lawrence, D. M., and Coauthors, 2011: Parameterization improvements and functional and structural advances in version 4 of the Community Land Model. J. Adv. Model. Earth Syst., 3, M03001, https://doi.org/10.1029/2011MS00045.

    • Search Google Scholar
    • Export Citation
  • Levine, A. F., M. J. McPhaden, and D. M. Frierson, 2017: The impact of the AMO on multidecadal ENSO variability. Geophys. Res. Lett., 44, 38773886, https://doi.org/10.1002/2017GL072524.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • L’Heureux, M. L., M. K. Tippett, and A. G. Barnston, 2015: Characterizing ENSO coupled variability and its impact on North American seasonal precipitation and temperature. J. Climate, 28, 42314245, https://doi.org/10.1175/JCLI-D-14-00508.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lin, I.-I., and Coauthors, 2020: ENSO and tropical cyclones. El Niño Southern Oscillation in a Changing Climate, Geophys. Monogr., Vol. 253, Amer. Geophys. Union, 377–408, https://doi.org/10.1002/9781119548164.ch17.

    • Crossref
    • Export Citation
  • Liu, W., and Z. Liu, 2014: Assessing the stability of the Atlantic meridional overturning circulation of the past, present, and future. J. Meteor. Res., 28, 803819, https://doi.org/10.1007/s13351-014-4006-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, W., and A. Hu, 2015: The role of the PMOC in modulating the deglacial shift of the ITCZ. Climate Dyn., 45, 30193034, https://doi.org/10.1007/s00382-015-2520-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, W., A. V. Fedorov, S.-P. Xie, and S. Hu, 2020: Climate impacts of a weakened Atlantic Meridional Overturning Circulation in a warming climate. Sci. Adv., 6, eaaz4876, https://doi.org/10.1126/sciadv.aaz4876.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McGee, D., A. Donohoe, J. Marshall, and D. Ferreira, 2014: Changes in ITCZ location and cross-equatorial heat transport at the Last Glacial Maximum, Heinrich Stadial 1, and the mid-Holocene. Earth Planet. Sci. Lett., 390, 6979, https://doi.org/10.1016/j.epsl.2013.12.043.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McGraw, M. C., and E. A. Barnes, 2018: Memory matters: A case for Granger causality in climate variability studies. J. Climate, 31, 32893300, https://doi.org/10.1175/JCLI-D-17-0334.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McGregor, S., A. Timmermann, N. Schneider, M. F. Stuecker, and M. H. England, 2012: The effect of the South Pacific convergence zone on the termination of El Niño events and the meridional asymmetry of ENSO. J. Climate, 25, 55665586, https://doi.org/10.1175/JCLI-D-11-00332.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McPhaden, M. J., S. E. Zebiak, and M. H. Glantz, 2006: ENSO as an integrating concept in Earth science. Science, 314, 17401745, https://doi.org/10.1126/science.1132588.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Meehl, G. A., and Coauthors, 2021: Atlantic and Pacific tropics connected by mutually interactive decadal-timescale processes. Nat. Geosci., 14, 3642, https://doi.org/10.1038/s41561-020-00669-x.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Meinen, C. S., and M. J. McPhaden, 2000: Observations of warm water volume changes in the equatorial Pacific and their relationship to El Niño and La Niña. J. Climate, 13, 35513559, https://doi.org/10.1175/1520-0442(2000)013<3551:OOWWVC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Molina, M. J., J. T. Allen, and V. A. Gensini, 2018: The Gulf of Mexico and ENSO influence on subseasonal and seasonal CONUS winter tornado variability. J. Appl. Meteor. Climatol., 57, 24392463, https://doi.org/10.1175/JAMC-D-18-0046.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Moreno-Chamarro, E., J. Marshall, and T. Delworth, 2020: Linking ITCZ migrations to the AMOC and North Atlantic/Pacific SST decadal variability. J. Climate, 33, 893905, https://doi.org/10.1175/JCLI-D-19-0258.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • NCEI, 2007: NOAA Optimum Interpolation 1/4 Degree Daily Sea Surface Temperature Analysis. Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory, accessed 18 June 2021, https://doi.org/10.5065/EM0T-1D34.

    • Crossref
    • Export Citation
  • Neale, R. B., and Coauthors, 2010: Description of the NCAR Community Atmosphere Model (CAM5.0). NCAR Tech. Note NCAR/TN-486+STR, 268 pp., www.cesm.ucar.edu/models/cesm1.1/cam/docs/description/cam5_desc.pdf.

  • Neelin, J. D., F.-F. Jin, and H.-H. Syu, 2000: Variations in ENSO phase locking. J. Climate, 13, 25702590, https://doi.org/10.1175/1520-0442(2000)013<2570:VIEPL>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Okazaki, Y., A. Timmermann, L. Menviel, N. Harada, A. Abe-Ouchi, M. Chikamoto, A. Mouchet, and H. Asahi, 2010: Deepwater formation in the North Pacific during the last glacial termination. Science, 329, 200204, https://doi.org/10.1126/science.1190612.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Parker, A., and C. Ollier, 2016: There is no real evidence for a diminishing trend of the Atlantic meridional overturning circulation. J. Ocean Eng. Sci., 1, 3035, https://doi.org/10.1016/j.joes.2015.12.007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Polo, I., J. Robson, R. Sutton, and M. A. Balmaseda, 2014: The importance of wind and buoyancy forcing for the boundary density variations and the geostrophic component of the AMOC at 26°N. J. Phys. Oceanogr., 44, 23872408, https://doi.org/10.1175/JPO-D-13-0264.1.

    • Crossref
    • 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, 319324, https://doi.org/10.1007/s003820050284.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rae, J. W., and Coauthors, 2020: Overturning circulation, nutrient limitation, and warming in the Glacial North Pacific. Sci. Adv., 6, eabd1654, https://doi.org/10.1126/sciadv.abd1654.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rahmstorf, S., J. E. Box, G. Feulner, M. E. Mann, A. Robinson, S. Rutherford, and E. J. Schaffernicht, 2015: Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation. Nat. Climate Change, 5, 475480, https://doi.org/10.1038/nclimate2554.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rashid, H. A., S. B. Power, and J. R. Knight, 2010: Impact of multidecadal fluctuations in the Atlantic thermohaline circulation on Indo-Pacific climate variability in a coupled GCM. J. Climate, 23, 40384044, https://doi.org/10.1175/2010JCLI3430.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Richter, I., S.-P. Xie, Y. Morioka, T. Doi, B. Taguchi, and S. Behera, 2017: Phase locking of equatorial Atlantic variability through the seasonal migration of the ITCZ. Climate Dyn., 48, 36153629, https://doi.org/10.1007/s00382-016-3289-y.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ruprich-Robert, Y., and C. Cassou, 2015: Combined influences of seasonal East Atlantic Pattern and North Atlantic Oscillation to excite Atlantic multidecadal variability in a climate model. Climate Dyn., 44, 229253, https://doi.org/10.1007/s00382-014-2176-7.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Russell, A. M., and A. Gnanadesikan, 2014: Understanding multidecadal variability in ENSO amplitude. J. Climate, 27, 40374051, https://doi.org/10.1175/JCLI-D-13-00147.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rustic, G. T., P. J. Polissar, A. C. Ravelo, and S. M. White, 2020: Modulation of late Pleistocene ENSO strength by the tropical Pacific thermocline. Nat. Commun., 11, 5377, https://doi.org/10.1038/s41467-020-19161-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Saenko, O. A., A. Schmittner, and A. J. Weaver, 2004: The Atlantic–Pacific seesaw. J. Climate, 17, 20332038, https://doi.org/10.1175/1520-0442(2004)017<2033:TAS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schneider, T., T. Bischoff, and G. H. Haug, 2014: Migrations and dynamics of the intertropical convergence zone. Nature, 513, 4553, https://doi.org/10.1038/nature13636.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schott, F. A., J. P. Mccreary, and G. C. Johnson, 2004: Shallow overturning circulations of the tropical-subtropical oceans. Earth’s Climate: The Ocean–Atmosphere Interaction, Geophys. Monogr., Vol. 147, Amer. Geophys. Union, 261–304, https://doi.org/10.1029/147GM15.

    • Crossref
    • Export Citation
  • Seager, R., D. S. Battisti, J. Yin, N. Gordon, N. Naik, A. C. Clement, and M. A. Cane, 2002: Is the Gulf Stream responsible for Europe’s mild winters? Quart. J. Roy. Meteor. Soc., 128, 25632586, https://doi.org/10.1256/qj.01.128.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Seidov, D., and B. J. Haupt, 2003: Freshwater teleconnections and ocean thermohaline circulation. Geophys. Res. Lett., 30, 1329, https://doi.org/10.1029/2002GL016564.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sigmond, M., J. C. Fyfe, O. A. Saenko, and N. C. Swart, 2020: Ongoing AMOC and related sea-level and temperature changes after achieving the Paris targets. Nat. Climate Change, 10, 672677, https://doi.org/10.1038/s41558-020-0786-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Smeed, D., G. McCarthy, D. Rayner, B. Moat, W. Johns, M. Baringer, and C. Meinen, 2016: Atlantic meridional overturning circulation observed by the RAPID-MOCHA-WBTS (RAPID-Meridional Overturning Circulation and Heatflux Array-Western Boundary Time Series) array at 26N from 2004 to 2015. British Oceanographic Data Centre, Natural Environment Research Council, accessed 1 January 2021, https://doi.org/10.5285/35784047-9b82-2160-e053-6c86abc0c91b.

    • Crossref
    • Export Citation
  • Stein, K., A. Timmermann, N. Schneider, F.-F. Jin, and M. F. Stuecker, 2014: ENSO seasonal synchronization theory. J. Climate, 27, 52855310, https://doi.org/10.1175/JCLI-D-13-00525.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Stocker, T. F., and W. S. Broecker, 1994: Observation and modeling of North Atlantic deep water formation and its variability: Introduction. J. Geophys. Res., 99, 12 31712 317, https://doi.org/10.1029/94JC00956.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Stuecker, M. F., F.-F. Jin, and A. Timmermann, 2015: El Niño-Southern Oscillation frequency cascade. Proc. Natl. Acad. Sci. USA, 112, 13 49013 495, https://doi.org/10.1073/pnas.1508622112.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sun, Y., F. Wang, and D.-Z. Sun, 2016: Weak ENSO asymmetry due to weak nonlinear air–sea interaction in CMIP5 climate models. Adv. Atmos. Sci., 33, 352364, https://doi.org/10.1007/s00376-015-5018-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sutton, R. T., and D. L. Hodson, 2005: Atlantic Ocean forcing of North American and European summer climate. Science, 309, 115118, https://doi.org/10.1126/science.1109496.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Timmermann, A., S. An, U. Krebs, and H. Goosse, 2005: ENSO suppression due to weakening of the North Atlantic thermohaline circulation. J. Climate, 18, 31223139, https://doi.org/10.1175/JCLI3495.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Timmermann, A., and Coauthors, 2007: The influence of a weakening of the Atlantic meridional overturning circulation on ENSO. J. Climate, 20, 48994919, https://doi.org/10.1175/JCLI4283.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Torrence, C., and G. P. Compo, 1998: A practical guide to wavelet analysis. Bull. Amer. Meteor. Soc., 79, 6178, https://doi.org/10.1175/1520-0477(1998)079<0061:APGTWA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., and J. T. Fasullo, 2017: Atlantic meridional heat transports computed from balancing Earth’s energy locally. Geophys. Res. Lett., 44, 19191927, https://doi.org/10.1002/2016GL072475.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., Y. Zhang, J. T. Fasullo, and L. Cheng, 2019: Observation-based estimates of global and basin ocean meridional heat transport time series. J. Climate, 32, 45674583, https://doi.org/10.1175/JCLI-D-18-0872.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tziperman, E., S. E. Zebiak, and M. A. Cane, 1997: Mechanisms of seasonal–ENSO interaction. J. Atmos. Sci., 54, 6171, https://doi.org/10.1175/1520-0469(1997)054<0061:MOSEI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • van Oldenborgh, G. J., L. A. te Raa, H. A. Dijkstra, and S. Y. Philip, 2009: Frequency-or amplitude-dependent effects of the Atlantic meridional overturning on the tropical Pacific Ocean. Ocean Sci., 5, 293301, https://doi.org/10.5194/os-5-293-2009.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Waldman, R., J. Hirschi, A. Voldoire, C. Cassou, and R. Msadek, 2021: Clarifying the relation between AMOC and thermal wind: Application to the centennial variability in a coupled climate model. J. Phys. Oceanogr., 51, 343364, https://doi.org/10.1175/JPO-D-19-0284.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, B., and Y. Wang, 1999: Dynamics of the ITCZ–equatorial cold tongue complex and causes of the Latitudinal climate asymmetry. J. Climate, 12, 18301847, https://doi.org/10.1175/1520-0442(1999)012<1830:DOTIEC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Weaver, A. J., C. M. Bitz, A. F. Fanning, and M. Holland, 1999: Thermohaline circulation: High-latitude phenomena and the difference between the Pacific and Atlantic. Annu. Rev. Earth Planet. Sci., 27, 231285, https://doi.org/10.1146/annurev.earth.27.1.231.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Weaver, A. J., and Coauthors, 2012: Stability of the Atlantic meridional overturning circulation: A model intercomparison. Geophys. Res. Lett., 39, L20709, https://doi.org/10.1029/2012GL053763.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Weijer, W., and Coauthors, 2019: Stability of the Atlantic Meridional Overturning Circulation: A review and synthesis. J. Geophys. Res. Oceans, 124, 53365375, https://doi.org/10.1029/2019JC015083.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wen, C., A. Kumar, Y. Xue, and M. McPhaden, 2014: Changes in tropical Pacific thermocline depth and their relationship to ENSO after 1999. J. Climate, 27, 72307249, https://doi.org/10.1175/JCLI-D-13-00518.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Williamson, M. S., M. Collins, S. S. Drijfhout, R. Kahana, J. V. Mecking, and T. M. Lenton, 2018: Effect of AMOC collapse on ENSO in a high resolution general circulation model. Climate Dyn., 50, 25372552, https://doi.org/10.1007/s00382-017-3756-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Willis, J. K., 2010: Can in situ floats and satellite altimeters detect long-term changes in Atlantic Ocean overturning? Geophys. Res. Lett., 37, L06602, https://doi.org/10.1029/2010GL042372.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Woodgate, R. A., and K. Aagaard, 2005: Revising the Bering Strait freshwater flux into the Arctic Ocean. Geophys. Res. Lett., 32, L02602, https://doi.org/10.1029/2004GL021747.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yu, H., and Coauthors, 2015: The fertilizing role of African dust in the Amazon rainforest: A first multiyear assessment based on data from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations. Geophys. Res. Lett., 42, 19841991, https://doi.org/10.1002/2015GL063040.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yu, S., and M. S. Pritchard, 2019: A strong role for the AMOC in partitioning global energy transport and shifting ITCZ position in response to latitudinally discrete solar forcing in CESM1.2. J. Climate, 32, 22072226, https://doi.org/10.1175/JCLI-D-18-0360.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zebiak, S. E., and M. A. Cane, 1987: A model El Niño–Southern Oscillation. Mon. Wea. Rev., 115, 22622278, https://doi.org/10.1175/1520-0493(1987)115<2262:AMENO>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zeller, M., S. McGregor, and P. Spence, 2019: Hemispheric asymmetry of the Pacific shallow meridional overturning circulation. J. Geophys. Res. Oceans, 124, 57655786, https://doi.org/10.1029/2018JC014840.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, J., and Coauthors, 2021: On the connection between AMOC and observed land precipitation in Northern Hemisphere: A comparison of the AMOC indicators. Climate Dyn., 56, 651664, https://doi.org/10.1007/s00382-020-05496-9.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, R., and T. L. Delworth, 2005: Simulated tropical response to a substantial weakening of the Atlantic thermohaline circulation. J. Climate, 18, 18531860, https://doi.org/10.1175/JCLI3460.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, R., R. Sutton, G. Danabasoglu, Y.-O. Kwon, R. Marsh, S. G. Yeager, D. E. Amrhein, and C. M. Little, 2019: A review of the role of the Atlantic meridional overturning circulation in Atlantic multidecadal variability and associated climate impacts. Rev. Geophys., 57, 316375, https://doi.org/10.1029/2019RG000644.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, T., and D.-Z. Sun, 2014: ENSO asymmetry in CMIP5 models. J. Climate, 27, 40704093, https://doi.org/10.1175/JCLI-D-13-00454.1.

  • Zhang, T., X. Shao, and S. Li, 2017: Impacts of atmospheric processes on ENSO asymmetry: A comparison between CESM1 and CCSM4. J. Climate, 30, 97439762, https://doi.org/10.1175/JCLI-D-17-0360.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
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Response of Global SSTs and ENSO to the Atlantic and Pacific Meridional Overturning Circulations

Maria J. MolinaaClimate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, Colorado

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Aixue HuaClimate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, Colorado

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Gerald A. MeehlaClimate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, Colorado

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Abstract

Consequences from a slowdown or collapse of the Atlantic meridional overturning circulation (AMOC) could include modulations to El Niño–Southern Oscillation (ENSO) and development of the Pacific meridional overturning circulation (PMOC). Despite potential ramifications to the global climate, our understanding of the influence of various AMOC and PMOC states on ENSO and global sea surface temperatures (SSTs) remains limited. Five multicentennial, fully coupled model simulations created with the Community Earth System Model were used to explore the influence of AMOC and PMOC on global SSTs and ENSO. We found that the amplitude of annual cycle SSTs across the tropical Pacific decreases and ENSO amplitude increases as a result of an AMOC shutdown, irrespective of PMOC development. However, active deep overturning circulations in both the Atlantic and Pacific basins reduce ENSO amplitude and variance of monthly SSTs globally. The underlying physical reasons for changes to global SSTs and ENSO are also discussed, with the atmospheric and oceanic mechanisms that drive changes to ENSO amplitude differing based on PMOC state. These results suggest that if climate simulations projecting AMOC weakening are realized, compounding climate impacts could occur given the far-reaching ENSO teleconnections to extreme weather and climate events. More broadly, these results provide us with insight into past geologic era climate states, when PMOC was active.

Significance Statement

The global-scale ocean circulation named the Atlantic meridional overturning circulation (AMOC) could be slowing due to climate change. Studies suggest that a slowdown of AMOC could trigger the formation of a Pacific counterpart, which would transport upper-ocean water into the North Pacific that is warmer and saltier than present day. Using several century-scale, fully coupled climate model experiments, our study shows that different states of these circulations can dramatically alter Earth’s climate and ocean temperatures, contributing to our understanding of potential future and past geological era climates. Importantly, we show that an AMOC slowdown could increase the strength of El Niño–Southern Oscillation, whether a Pacific meridional overturning circulation develops or not, which could amplify climate extremes via tropical–extratropical teleconnections.

© 2021 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: Maria J. Molina, molina@ucar.edu

Abstract

Consequences from a slowdown or collapse of the Atlantic meridional overturning circulation (AMOC) could include modulations to El Niño–Southern Oscillation (ENSO) and development of the Pacific meridional overturning circulation (PMOC). Despite potential ramifications to the global climate, our understanding of the influence of various AMOC and PMOC states on ENSO and global sea surface temperatures (SSTs) remains limited. Five multicentennial, fully coupled model simulations created with the Community Earth System Model were used to explore the influence of AMOC and PMOC on global SSTs and ENSO. We found that the amplitude of annual cycle SSTs across the tropical Pacific decreases and ENSO amplitude increases as a result of an AMOC shutdown, irrespective of PMOC development. However, active deep overturning circulations in both the Atlantic and Pacific basins reduce ENSO amplitude and variance of monthly SSTs globally. The underlying physical reasons for changes to global SSTs and ENSO are also discussed, with the atmospheric and oceanic mechanisms that drive changes to ENSO amplitude differing based on PMOC state. These results suggest that if climate simulations projecting AMOC weakening are realized, compounding climate impacts could occur given the far-reaching ENSO teleconnections to extreme weather and climate events. More broadly, these results provide us with insight into past geologic era climate states, when PMOC was active.

Significance Statement

The global-scale ocean circulation named the Atlantic meridional overturning circulation (AMOC) could be slowing due to climate change. Studies suggest that a slowdown of AMOC could trigger the formation of a Pacific counterpart, which would transport upper-ocean water into the North Pacific that is warmer and saltier than present day. Using several century-scale, fully coupled climate model experiments, our study shows that different states of these circulations can dramatically alter Earth’s climate and ocean temperatures, contributing to our understanding of potential future and past geological era climates. Importantly, we show that an AMOC slowdown could increase the strength of El Niño–Southern Oscillation, whether a Pacific meridional overturning circulation develops or not, which could amplify climate extremes via tropical–extratropical teleconnections.

© 2021 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: Maria J. Molina, molina@ucar.edu
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