• 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, 22052231, https://doi.org/10.1175/1520-0442(2002)015<2205:TABTIO>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bellenger, H., É. Guilyardi, J. Leloup, M. Lengaigne, and J. Vialard, 2014: ENSO representation in climate models: From CMIP3 to CMIP5. Climate Dyn., 42, 19992018, https://doi.org/10.1007/s00382-013-1783-z.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chakravorty, S., J. S. Chowdary, and C. Gnanaseelan, 2013: Spring asymmetric mode in the tropical Indian Ocean: Role of El Niño and IOD. Climate Dyn., 40, 14671481, https://doi.org/10.1007/s00382-012-1340-1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chang, C.-P., Y.-S. Zhang, and T. Li, 2000: Interannual and interdecadal variations of the East Asian summer monsoon and tropical Pacific SSTs. Part I: Roles of the subtropical ridge. J. Climate, 13, 43104325, https://doi.org/10.1175/1520-0442(2000)013<4310:IAIVOT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, W., R. Lu, and B. Dong, 2014: Intensified anticyclonic anomaly over the western North Pacific during El Niño decaying summer under a weakened Atlantic thermohaline circulation. J. Geophys. Res. Atmos., 119, 13 63713 650, https://doi.org/10.1002/2014JD022199.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, Z., Z. Wen, R. Wu, X. Lin, and J. Wang, 2016: Relative importance of tropical SST anomalies in maintaining the western North Pacific anomalous anticyclone during El Niño to La Niña transition years. Climate Dyn., 46, 10271041, https://doi.org/10.1007/s00382-015-2630-1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chowdary, J. S., C. Gnanaseelan, and S.-P. Xie, 2009: Westward propagation of barrier layer formation in the 2006–07 Rossby wave event over the tropical southwest Indian Ocean. Geophys. Res. Lett., 36, L04607, https://doi.org/10.1029/2008GL036642.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chowdary, J. S., S.-P. Xie, H. Tokinaga, Y. M. Okumura, H. Kubota, N. Johnson, and X.-T. Zheng, 2012: Interdecadal variations in ENSO teleconnection to the Indo-western Pacific for 1870–2007. J. Climate, 25, 17221744, https://doi.org/10.1175/JCLI-D-11-00070.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Delworth, T. L., and Coauthors, 2006: GFDL’s CM2 global coupled climate models. Part I: Formulation and simulation characteristics. J. Climate, 19, 643674, https://doi.org/10.1175/JCLI3629.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Du, Y., S.-P. Xie, G. Huang, and K. Hu, 2009: Role of air–sea interaction in the long persistence of El Niño–induced north Indian Ocean warming. J. Climate, 22, 20232038, https://doi.org/10.1175/2008JCLI2590.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Du, Y., S. Xie, Y. Yang, X. Zheng, L. Liu, and G. Huang, 2013: Indian Ocean variability in the CMIP5 multimodel ensemble: The basin mode. J. Climate, 26, 72407266, https://doi.org/10.1175/JCLI-D-12-00678.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Fan, L., S.-I. Shin, Q. Liu, and Z. Liu, 2013: Relative importance of tropical SST anomalies in forcing East Asian summer monsoon circulation. Geophys. Res. Lett., 40, 24712477, https://doi.org/10.1002/grl.50494.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Giese, B. S., and S. Ray, 2011: El Niño variability in Simple Ocean Data Assimilation (SODA), 1871–2008. J. Geophys. Res., 116, C02024, https://doi.org/10.1029/2010JC006695.

    • Search Google Scholar
    • Export Citation
  • Gill, A. E., 1980: Some simple solutions for heat-induced tropical circulation. Quart. J. Roy. Meteor. Soc., 106, 447462, https://doi.org/10.1002/qj.49710644905.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hu, K., G. Huang, X.-T. Zheng, S.-P. Xie, X. Qu, Y. Du, and L. Liu, 2014: Interdecadal variations in ENSO influences on northwest Pacific–East Asian early summertime climate simulated in CMIP5 models. J. Climate, 27, 59825998, https://doi.org/10.1175/JCLI-D-13-00268.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Huang, B.-H., and J. Shukla, 2007a: Mechanisms for the interannual variability in the tropical Indian Ocean. Part I: The role of remote forcing from the tropical Pacific. J. Climate, 20, 29172936, https://doi.org/10.1175/JCLI4151.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Huang, B.-H., and J. Shukla, 2007b: Mechanisms for the interannual variability in the tropical Indian Ocean. Part II: Regional processes. J. Climate, 20, 29372960, https://doi.org/10.1175/JCLI4169.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Huang, B.-Y., and Coauthors, 2015: Extended Reconstructed Sea Surface Temperature version 4 (ERSST.v4). Part I: Upgrades and intercomparisons. J. Climate, 28, 911930, https://doi.org/10.1175/JCLI-D-14-00006.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Huang, G., K. Hu, and S.-P. Xie, 2010: Strengthening of tropical Indian Ocean teleconnection to the northwest Pacific since the mid-1970s: An atmospheric GCM study. J. Climate, 23, 52945304, https://doi.org/10.1175/2010JCLI3577.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Huang, R. H., and Y. F. Wu, 1989: The influence of ENSO on the summer climate change in China and its mechanism. Adv. Atmos. Sci., 6, 2132, https://doi.org/10.1007/BF02656915.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Izumo, T., C. B. Boyer Montégut, J.-J. Luo, S. K. Behera, S. Masson, and T. Yamagata, 2008: The role of the western Arabian Sea upwelling in Indian monsoon rainfall variability. J. Climate, 21, 56035623, https://doi.org/10.1175/2008JCLI2158.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437471, https://doi.org/10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kamae, Y., X. Li, S.-P. Xie, and H. Ueda, 2017: Atlantic effects on recent decadal trends in global monsoon. Climate Dyn., 49, 34433455, https://doi.org/10.1007/s00382-017-3522-3.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Klein, S. A., B. J. Soden, and N.-C. Lau, 1999: Remote sea surface temperature variations during ENSO: Evidence for a tropical atmospheric bridge. J. Climate, 12, 917932, https://doi.org/10.1175/1520-0442(1999)012<0917:RSSTVD>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kosaka, Y., and H. Nakamura, 2006: Structure and dynamics of the summertime Pacific–Japan teleconnection pattern. Quart. J. Roy. Meteor. Soc., 132, 20092030, https://doi.org/10.1256/qj.05.204.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kosaka, Y., and S.-P. Xie, 2013: Recent global-warming hiatus tied to equatorial Pacific surface cooling. Nature, 501, 403407, https://doi.org/10.1038/nature12534.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kosaka, Y., and S.-P. Xie, 2016: The tropical Pacific as a key pacemaker of the variable rates of global warming. Nat. Geosci., 9, 669673, https://doi.org/10.1038/ngeo2770.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kosaka, Y., S.-P. Xie, N.-C. Lau, and G. A. Vecchi, 2013: Origin of seasonal predictability for summer climate over the northwestern Pacific. Proc. Natl. Acad. Sci. USA, 110, 75747579, https://doi.org/10.1073/pnas.1215582110.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kubota, H., Y. Kosaka, and S.-P. Xie, 2016: A 117-year long index of the Pacific-Japan pattern with application to interdecadal variability. Int. J. Climatol., 36, 15751589, https://doi.org/10.1002/joc.4441.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lau, N.-C., and M. J. Nath, 2000: Impact of ENSO on the variability of the Asian–Australian monsoons as simulated in GCM experiments. J. Climate, 13, 42874309, https://doi.org/10.1175/1520-0442(2000)013<4287:IOEOTV>2.0.CO;2.

    • 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
  • Li, G., and S.-P. Xie, 2014: Tropical biases in CMIP5 multimodel ensemble: The excessive equatorial Pacific cold tongue and double ITCZ problems. J. Climate, 27, 17651780, https://doi.org/10.1175/JCLI-D-13-00337.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Li, T., B. Wang, B. Wu, T. Zhou, C.-P. Chang, and R. Zhang, 2017: Theories on formation of an anomalous anticyclone in western North Pacific during El Niño: A review. J. Meteor. Res., 31, 9871006, https://doi.org/10.1007/s13351-017-7147-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, Z., and M. Alexander, 2007: Atmospheric bridge, oceanic tunnel, and global climatic teleconnections. Rev. Geophys., 45, RG2005, https://doi.org/10.1029/2005RG000172.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Masumoto, Y., and G. Meyers, 1998: Forced Rossby waves in the southern tropical Indian Ocean. J. Geophys. Res., 103, 27 58927 602, https://doi.org/10.1029/98JC02546.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Matsuno, T., 1966: Quasi-geostrophic motions in the equatorial area. J. Meteor. Soc. Japan, 44, 2543, https://doi.org/10.2151/jmsj1965.44.1_25.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nigam, S., and H.-S. Shen, 1993: Structure of oceanic and atmospheric low-frequency variability over the tropical Pacific and Indian Oceans. Part I: COADS observations. J. Climate, 6, 657676, https://doi.org/10.1175/1520-0442(1993)006<0657:SOOAAL>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nitta, T., 1986: Long-term variations of cloud amount in the western Pacific region. J. Meteor. Soc. Japan, 64, 373390, https://doi.org/10.2151/jmsj1965.64.3_373.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Okumura, Y. M., and C. Deser, 2010: Asymmetry in the duration of El Niño and La Niña. J. Climate, 23, 58265843, https://doi.org/10.1175/2010JCLI3592.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Okumura, Y. M., M. Ohba, C. Deser, and H. Ueda, 2011: A proposed mechanism for the asymmetric duration of El Niño and La Niña. J. Climate, 24, 38223829, https://doi.org/10.1175/2011JCLI3999.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Perigaud, C., and P. Delecluse, 1993: Interannual sea level variations in the tropical Indian Ocean from Geosat and shallow water simulations. J. Phys. Oceanogr., 23, 19161934, https://doi.org/10.1175/1520-0485(1993)023<1916:ISLVIT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schott, F. A., S.-P. Xie, and J. P. McCreary Jr., 2009: Indian Ocean circulation and climate variability. Rev. Geophys., 47, RG1002, https://doi.org/10.1029/2007RG000245.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Song, F., and T. Zhou, 2015: The crucial role of internal variability in modulating the decadal variation of the East Asian summer monsoon–ENSO relationship during the twentieth century. J. Climate, 28, 70937107, https://doi.org/10.1175/JCLI-D-14-00783.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Stuecker, M.-F., F.-F. Jin, A. Timmermann, and S. McGregor, 2015: Combination mode dynamics of the anomalous northwest Pacific anticyclone. J. Climate, 28, 10931111, https://doi.org/10.1175/JCLI-D-14-00225.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Terao, T., and T. Kubota, 2005: East–west SST contrast over the tropical oceans and the post El Niño western North Pacific summer monsoon. Geophys. Res. Lett., 32, L15706, https://doi.org/10.1029/2005GL023010.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tokinaga, H., S.-P. Xie, A. Timmermann, S. McGregor, T. Ogata, H. Kubota, and Y. M. Okumura, 2012: Regional patterns of tropical Indo-Pacific climate change: Evidence of the Walker circulation weakening. J. Climate, 25, 16891710, https://doi.org/10.1175/JCLI-D-11-00263.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, B., R. Wu, and X. Fu, 2000: Pacific–East Asian teleconnection: How does ENSO affect East Asian climate? J. Climate, 13, 15171536, https://doi.org/10.1175/1520-0442(2000)013<1517:PEATHD>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, B., R. Wu, and T. Li, 2003: Atmosphere–warm ocean interaction and its impacts on Asian-Australian monsoon variation. J. Climate, 16, 11951211, https://doi.org/10.1175/1520-0442(2003)16<1195:AOIAII>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, B., J. Yang, T. Zhou, and B. Wang, 2008: Interdecadal changes in the major modes of Asian–Australian monsoon variability: Strengthening relationship with ENSO since the late 1970s. J. Climate, 21, 17711789, https://doi.org/10.1175/2007JCLI1981.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, B., J. Li, and Q. He, 2017: Variable and robust East Asian monsoon rainfall response to El Niño over the past 60 years (1957–2016). Adv. Atmos. Sci., 34, 12351248, https://doi.org/10.1007/s00376-017-7016-3.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wu, B., T. Zhou, and T. Li, 2017a: Atmospheric dynamic and thermodynamic processes driving the western North Pacific anomalous anticyclone during El Niño. Part I: Maintenance mechanisms. J. Climate, 30, 96219635, https://doi.org/10.1175/JCLI-D-16-0489.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wu, B., T. Zhou, and T. Li, 2017b: Atmospheric dynamic and thermodynamic processes driving the western North Pacific anomalous anticyclone during El Niño. Part II: Formation processes. J. Climate, 30, 96379650, https://doi.org/10.1175/JCLI-D-16-0495.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wu, R., and B. Wang, 2002: A contrast of the East Asian summer monsoon–ENSO relationship between 1962–77 and 1978–93. J. Climate, 15, 32663279, https://doi.org/10.1175/1520-0442(2002)015<3266:ACOTEA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wu, R., and B.P. Kirtman, 2006: Changes in spread and predictability associated with ENSO in an ensemble Coupled GCM. J. Climate, 19, 43784396, https://doi.org/10.1175/JCLI3872.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wu, R., and S.-W. Yeh, 2010: A further study of the tropical Indian Ocean asymmetric mode in boreal spring. J. Geophys. Res., 115, D08101, https://doi.org/10.1029/2009JD012999.

    • Search Google Scholar
    • Export Citation
  • Wu, R., Z. Hu, and B. P. Kirtman, 2003: Evolution of ENSO-related rainfall anomalies in East Asia. J. Climate, 16, 37423758, https://doi.org/10.1175/1520-0442(2003)016<3742:EOERAI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wu, R., J. L. Kinter, and B. P. Kirtman, 2005: Discrepancy of interdecadal changes in the Asian region among the NCEP–NCAR reanalysis, objective analyses, and observations. J. Climate, 18, 30483067, https://doi.org/10.1175/JCLI3465.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wu, R., B. P. Kirtman, and V. Krishnamurthy, 2008: An asymmetric mode of tropical Indian Ocean rainfall variability in boreal spring. J. Geophys. Res., 113, D05104, https://doi.org/10.1029/2007JD009316.

    • Search Google Scholar
    • Export Citation
  • Wu, R., W. Chen, G. Wang, and K. Hu, 2014: Relative contribution of ENSO and East Asian winter monsoon to the South China Sea SST anomalies during ENSO decaying years. J. Geophys. Res. Atmos., 119, 50465064, https://doi.org/10.1002/2013JD021095.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., and Z.-Q. Zhou, 2017: Seasonal modulations of El Niño–related atmospheric variability: Indo–western Pacific Ocean feedback. J. Climate, 30, 34613472, https://doi.org/10.1175/JCLI-D-16-0713.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., H. Annamalai, F. A. Schott, and J. P. McCreary Jr., 2002: Structure and mechanisms of south Indian Ocean climate variability. J. Climate, 15, 864878, https://doi.org/10.1175/1520-0442(2002)015<0864:SAMOSI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., K. Hu, J. Hafner, H. Tokinaga, Y. Du, G. Huang, and T. Sampe, 2009: Indian Ocean capacitor effect on Indo-western Pacific climate during the summer following El Niño. J. Climate, 22, 730747, https://doi.org/10.1175/2008JCLI2544.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., Y. Du, G. Huang, X. Zheng, H. Tokinaga, K. Hu, and Q. Liu, 2010: Decadal shift in El Niño influences on Indo–western Pacific and East Asian climate in the 1970s. J. Climate, 23, 33523368, https://doi.org/10.1175/2010JCLI3429.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., Y. Kosaka, Y. Du, K. Hu, J. Chowdary, and G. Huang, 2016: Indo-western Pacific Ocean capacitor and coherent climate anomalies in post-ENSO summer: A review. Adv. Atmos. Sci., 33, 411432, https://doi.org/10.1007/s00376-015-5192-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yang, Y., S.-P. Xie, L. Wu, Y. Kosaka, N.-C. Lau, and G. A. Vecchi, 2015: Seasonality and predictability of the Indian Ocean dipole mode: ENSO forcing and internal variability. J. Climate, 28, 80218036, https://doi.org/10.1175/JCLI-D-15-0078.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yang, Y., S.-P. Xie, L. Wu, Y. Kosaka, and J. Li, 2017: ENSO forced and local variability of north tropical Atlantic SST: Model simulations and biases. Climate Dyn., https://doi.org/10.1007/s00382-017-3679-9.

    • Search Google Scholar
    • Export Citation
  • Zhang, R. H., A. Sumi, and M. Kimoto, 1996: Impact of El Niño on the East Asian monsoon: A diagnostic study of the ‘86/87 and ’91/92 events. J. Meteor. Soc. Japan, 74, 4962, https://doi.org/10.2151/jmsj1965.74.1_49.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhou, Z.-Q., S.-P. Xie, G. J. Zhang, and W. Zhou, 2018: Evaluating AMIP skill in simulating interannual variability over the Indo–western Pacific. J. Climate, 31, 22532265, https://doi.org/10.1175/JCLI-D-17-0123.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
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Indo-Western Pacific Climate Variability: ENSO Forcing and Internal Dynamics in a Tropical Pacific Pacemaker Simulation

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  • 1 Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China and Qingdao National Laboratory for Marine Science and Technology, Qingdao, China, and Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California
  • | 2 Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California, and Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China and Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
  • | 3 Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan
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Abstract

El Niño–Southern Oscillation (ENSO) peaks in boreal winter but its impact on Indo-western Pacific climate persists for another two seasons. Key ocean–atmosphere interaction processes for the ENSO effect are investigated using the Pacific Ocean–Global Atmosphere (POGA) experiment with a coupled general circulation model, where tropical Pacific sea surface temperature (SST) anomalies are restored to follow observations while the atmosphere and oceans are fully coupled elsewhere. The POGA shows skills in simulating the ENSO-forced warming of the tropical Indian Ocean and an anomalous anticyclonic circulation pattern over the northwestern tropical Pacific in the post–El Niño spring and summer. The 10-member POGA ensemble allows decomposing Indo-western Pacific variability into the ENSO forced and ENSO-unrelated (internal) components. Internal variability is comparable to the ENSO forcing in magnitude and independent of ENSO amplitude and phase. Random internal variability causes apparent decadal modulations of ENSO correlations over the Indo-western Pacific, which are high during epochs of high ENSO variance. This is broadly consistent with instrumental observations over the past 130 years as documented in recent studies. Internal variability features a sea level pressure pattern that extends into the north Indian Ocean and is associated with coherent SST anomalies from the Arabian Sea to the western Pacific, suggestive of ocean–atmosphere coupling.

© 2018 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: Shang-Ping Xie, sxie@ucsd.edu

Abstract

El Niño–Southern Oscillation (ENSO) peaks in boreal winter but its impact on Indo-western Pacific climate persists for another two seasons. Key ocean–atmosphere interaction processes for the ENSO effect are investigated using the Pacific Ocean–Global Atmosphere (POGA) experiment with a coupled general circulation model, where tropical Pacific sea surface temperature (SST) anomalies are restored to follow observations while the atmosphere and oceans are fully coupled elsewhere. The POGA shows skills in simulating the ENSO-forced warming of the tropical Indian Ocean and an anomalous anticyclonic circulation pattern over the northwestern tropical Pacific in the post–El Niño spring and summer. The 10-member POGA ensemble allows decomposing Indo-western Pacific variability into the ENSO forced and ENSO-unrelated (internal) components. Internal variability is comparable to the ENSO forcing in magnitude and independent of ENSO amplitude and phase. Random internal variability causes apparent decadal modulations of ENSO correlations over the Indo-western Pacific, which are high during epochs of high ENSO variance. This is broadly consistent with instrumental observations over the past 130 years as documented in recent studies. Internal variability features a sea level pressure pattern that extends into the north Indian Ocean and is associated with coherent SST anomalies from the Arabian Sea to the western Pacific, suggestive of ocean–atmosphere coupling.

© 2018 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: Shang-Ping Xie, sxie@ucsd.edu
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