[1] Ashok, K., S. K. Behera, S. A. Rao, et al., 2007: El Niño Modoki and its possible teleconnection. J. Geophys. Res. Oceans, 112, C11007. doi: 10.1029/2006JC003798
[2] Balmaseda, M. A., K. Mogensen, and A. T. Weaver, 2013: Evaluation of the ECMWF ocean reanalysis system ORAS4. Quart. J. Roy. Meteor. Soc., 139, 1132–1161. doi: 10.1002/qj.2063
[3] Barnston, A. G., M. K. Tippett, M. L. L’Heureux, et al., 2012: Skill of real-time seasonal ENSO model predictions during 2002–11: Is our capability increasing? Bull. Amer. Meteor. Soc., 93, 631–651. doi: 10.1175/BAMS-D-11-00111.1
[4] Barnston, A. G., M. K. Tippett, M. Ranganathan, et al., 2019: Deterministic skill of ENSO predictions from the North American Multimodel Ensemble. Climate Dyn., 53, 7215–7234. doi: 10.1007/s00382-017-3603-3
[5] Chen, D. K., T. Lian, C. B. Fu, et al., 2015: Strong influence of westerly wind bursts on El Niño diversity. Nat. Geosci., 8, 339–345. doi: 10.1038/ngeo2399
[6] Chen, L., Y. Q. Yu, and W. P. Zheng, 2016: Improved ENSO simulation from climate system model FGOALS-g1.0 to FGOALS-g2. Climate Dyn., 47, 2617–2634. doi: 10.1007/s00382-016-2988-8
[7] Chen, L., T. Li, B. Wang, et al., 2017: Formation mechanism for 2015/16 super El Niño. Sci. Rep., 7, 2975. doi: 10.1038/s41598-017-02926-3
[8] Dee, D. P., S. M. Uppala, A. J. Simmons, et al., 2011: The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553–597. doi: 10.1002/qj.828
[9] Grassi, B., G. Redaelli, P. O. Canziani, et al., 2012: Effects of the PDO phase on the tropical belt width. J. Climate, 25, 3282–3290. doi: 10.1175/JCLI-D-11-00244.1
[10] Harrison, D. E., and B. S. Giese, 1991: Episodes of surface westerly winds as observed from islands in the western tropical Pacific. J. Geophys. Res. Oceans, 96, 3221–3237. doi: 10.1029/90JC01775
[11] Harrison, D. E., and G. A. Vecchi, 1997: Westerly wind events in the tropical Pacific, 1986–95. J. Climate, 10, 3131–3156. doi: 10.1175/1520-0442(1997)010<3131:WWEITT>2.0.CO;2
[12] Hu, Z.-Z., A. Kumar, H.-L. Ren, et al., 2013: Weakened interannual variability in the tropical Pacific Ocean since 2000. J. Climate, 26, 2601–2613. doi: 10.1175/JCLI-D-12-00265.1
[13] Huang, B. Y., P. W. Thorne, V. F. Banzon, et al., 2017: Extended Reconstructed Sea Surface Temperature, version 5 (ERSSTv5): Upgrades, validations, and intercomparisons. J. Climate, 30, 8179–8205. doi: 10.1175/JCLI-D-16-0836.1
[14] Jin, F.-F., 1997: An equatorial ocean recharge paradigm for ENSO. Part I: Conceptual model. J. Atmos. Sci., 54, 811–829. doi: 10.1175/1520-0469(1997)054<0811:AEORPF>2.0.CO;2
[15] Keen, R. A., 1982: The role of cross-equatorial tropical cyclone pairs in the Southern Oscillation. Mon. Wea. Rev., 110, 1405–1416. doi: 10.1175/1520-0493(1982)110<1405:TROCET>2.0.CO;2
[16] Kiladis, G. N., G. A. Meehl, and K. M. Weickmann, 1994: Large-scale circulation associated with westerly wind bursts and deep convection over the western equatorial Pacific. J. Geophys. Res. Atmos., 99, 18527–18544. doi: 10.1029/94JD01486
[17] Li, T. M., 1997: Phase transition of the El Niño–Southern Oscillation: A stationary SST mode. J. Atmos. Sci., 54, 2872–2887. doi: 10.1175/1520-0469(1997)054<2872:PTOTEN>2.0.CO;2
[18] McPhaden, M. J., 2012: A 21st century shift in the relationship between ENSO SST and warm water volume anomalies. Geophys. Res. Lett., 39, L09706. doi: 10.1029/2012GL051826
[19] Min, Q. Y., J. Z. Su, R. H. Zhang, et al., 2015: What hindered the El Niño pattern in 2014? Geophys. Res. Lett., 42, 6762–6770. doi: 10.1002/2015GL064899
[20] Philander, S. G., 1990: El Niño, La Niña, and the Southern Oscillation. Academic Press, London, 1–289.
[21] Saha, S. K., S. Pokhrel, H. S. Chaudhari, et al., 2014: Improved simulation of Indian summer monsoon in latest NCEP climate forecast system free run. Int. J. Climatol., 34, 1628–1641. doi: 10.1002/joc.3791
[22] Schmid, C., R. L. Molinari, R. Sabina, et al., 2007: The real-time data management system for Argo profiling float observations. J. Atmos. Ocean. Technol., 24, 1608–1628. doi: 10.1175/JTECH2070.1
[23] Su, J. Z., B. Q. Xiang, B. Wang, et al., 2014: Abrupt termination of the 2012 Pacific warming and its implication on ENSO prediction. Geophys. Res. Lett., 41, 9058–9064. doi: 10.1002/2014GL062380
[24] Su, J. Z., R. H. Zhang, X. Y. Rong, et al., 2018: Sea surface temperature in the subtropical Pacific boosted the 2015 El Niño and hindered the 2016 La Niña. J. Climate, 31, 877–893. doi: 10.1175/JCLI-D-17-0379.1
[25] Timmermann, A., S.-I. An, J.-S. Kug, et al., 2018: El Niño–Southern Oscillation complexity. Nature, 559, 535–545. doi: 10.1038/s41586-018-0252-6
[26] Vecchi, G. A., and D. E. Harrison, 2000: Tropical Pacific sea surface temperature anomalies, El Niño, and equatorial westerly wind events. J. Climate, 13, 1814–1830. doi: 10.1175/1520-0442(2000)013<1814:TPSSTA>2.0.CO;2
[27] Yang, S., Z. N. Li, J.-Y. Yu, et al., 2018: El Niño–Southern Oscillation and its impact in the changing climate. Natl. Sci. Rev., 5, 840–857. doi: 10.1093/nsr/nwy046
[28] Zhao, M., H. H. Hendon, O. Alves, et al., 2013: Impact of salinity constraints on the simulated mean state and variability in a coupled seasonal forecast model. Mon. Wea. Rev., 141, 388–402. doi: 10.1175/MWR-D-11-00341.1
[29] Zhao, M., H. H. Hendon, O. Alves, et al., 2014: Impact of improved assimilation of temperature and salinity for coupled model seasonal forecasts. Climate Dyn., 42, 2565–2583. doi: 10.1007/s00382-014-2081-0
[30] Zhao, M., H. H. Hendon, O. Alves, et al., 2016: Weakened eastern Pacific El Niño predictability in the early twenty-first century. J. Climate, 29, 6805–6822. doi: 10.1175/JCLI-D-15-0876.1