This research was supported by NOAA under Grant NA66GP0370. We gratefully acknowledge the helpful comments from two anonymous reviewers.
An, S-I., , and B. Wang, 2001: Mechanisms of locking of the El Niño and La Niña mature phases to boreal winter. J. Climate, 14 , 2164–2176.
Battisti, D. S., 1988: Dynamics and thermodynamics of a warming event in a coupled tropical atmosphere–ocean model. J. Atmos. Sci., 45 , 2889–2919.
Chang, P., , L. Ji, , B. Wang, , and T. Li, 1995: Interactions between the seasonal cycle and El Niño–Southern Oscillation in an intermediate coupled ocean–atmosphere model. J. Atmos. Sci., 52 , 2353–2372.
Clement, A. C., , R. Seager, , and M. A. Cane, 1999: Orbital controls on the El Niño/Southern Oscillation and the tropical climate. Paleoceanography, 14 , 441–456.
Clement, A. C., , R. Seager, , and M. A. Cane, 2000: Suppression of El Niño during the mid-Holocene by changes in the earth’s orbit. Paleoceanography, 15 , 731–737.
Fedorov, A. V., , and S. G. H. Philander, 2001: A stability analysis of tropical ocean–atmosphere interactions: Bridging measurements and theory for El Niño. J. Climate, 14 , 3086–3101.
Giese, B. S., , and D. E. Harrison, 1990: Aspects of the Kelvin wave response to episodic wind forcing. J. Geophys. Res., 95 , 7289–7312.
Guilyardi, E., , P. Delecluse, , S. Gualdi, , and A. Navarra, 2003: Mechanisms for ENSO phase change in a coupled GCM. J. Climate, 16 , 1141–1158.
Jin, F-F., , J. D. Neelin, , and M. Ghil, 1996: El Niño/Southern Oscillation and the annual cycle: Subharmonic frequency-locking and aperiodicity. Physica D, 98 , 442–465.
Long, B., , and P. Chang, 1990: Propagation of an equatorial Kelvin wave in a varying thermocline. J. Phys. Oceanogr., 20 , 1826–1841.
Philander, S. G. H., , and W. J. Hurlin, 1988: The heat budget of the tropical Pacific Ocean in a simulation of the 1982/83 El Niño. J. Phys. Oceanogr., 18 , 926–931.
Timmermann, A., , S-I. An, , U. Krebs, , and H. Goosse, 2005: ENSO suppression due to weakening of the North Atlantic thermohaline circulation. J. Climate, 18 , 3122–3139.
Tziperman, E., , M. A. Cane, , S. E. Zebiak, , Y. Xue, , and B. Blumenthal, 1998: Locking of El Niño’s peak time to the end of the calendar year in the delayed oscillator picture of ENSO. J. Climate, 11 , 2191–2199.
Vintzileos, A., , P. Delecluse, , and R. Sadourny, 1999a: On the mechanisms in a tropical ocean–global atmosphere coupled general circulation model. Part I: Mean state and the seasonal cycle. Climate Dyn., 15 , 43–62.
Vintzileos, A., , P. Delecluse, , and R. Sadourny, 1999b: On the mechanisms in a tropical ocean–global atmosphere coupled general circulation model. Part II: Interannual variability and its relation to the seasonal cycle. Climate Dyn., 15 , 63–80.
Xie, S-P., 1995: Interaction between the annual and interannual variations in the equatorial Pacific. J. Phys. Oceanogr., 25 , 1930–1940.
Yang, J., , and J. J. O’Brien, 1993: A coupled atmosphere–ocean model in the tropics with different thermocline profiles. J. Climate, 6 , 1027–1041.
Zheng, Q., , R. D. Susanto, , X-H. Yan, , W. T. Liu, , and C-R. Ho, 1998: Observation of equatorial Kelvin solitary waves in a slowly varying thermocline. Nonlinear Processes Geophys., 5 , 153–165.