Summary
A coupled ocean-atmosphere anomaly model has been developed for simulating ENSO cycle and its mechanism-study in this paper. After a long model run, the coupled model is successful in demonstrating ENSO-like irregular interannual variability and corresponding horizontal spatial structures. Based on the simulated results, the dynamics and the thermodynamics of the model ENSO cycle have been investigated, and in particular the negative feedback mechanisms that act to oppose instability of air-sea interaction, inducing termination of warm and cold events, have been examined. A detailed analysis of the oceanic wave dynamical properties and heat budget of the SST changes in a representative cycle suggest that the negative feedback mechanism to check the unstable growth of a warm event obviously differs from that of a cold event. The mechanism that induces decay and termination of a cold event is closely related to the negative, delayed feedback effect produced by the oceanic dynamical wave reflection at the western boundary. However, independent of the wave reflection effect, the negative feedback mechanism by which the coupled system returns from a warm event is associated with a slowly eastward-propagating coupling mode. Accompanied with the strong unstable development of the equatorial positive SST anomaly, the anomalous upwelling of cold water generated off the equator and the nonlinear anomalous meridional advection generated in the equator west of instability area jointly restrain the instability and finally plunge the system from a mature warm phase into a weak cold phase. A comparison between the results from the present model and the previous works is also discussed in this paper.
Similar content being viewed by others
References
Anderson, D. L. T., McCreary, J. P., 1985: Slowly propagating disturbances in a coupled ocean-atmosphere model.J. Atmos. Sci.,42, 615–629.
Barnett, T. P., 1991: The interaction of multiple time scales in the tropical climate system.J. Climate,4, 269–285.
Battisti, D. S. 1988: The dynamics and thermodynamics of a warming event in a coupled tropical atmosphere-ocean model.J. Atmos. Sci.,45, 2889–2919.
Battisti, D. S., Hirst, A. C., 1989: Interannual variability in the tropical atmosphere-ocean system: Influence of the basic state and ocean geometry.J. Atmos. Sci.,46, 1687–1712.
Bjerknes, J. 1969: Atmospheric teleconnections from the equatorial Pacific.Mon. Wea. Rev.,97, 163–172.
Cane, M. A., Zebiak, S. E. 1985: A theory for El Nino and the Southern Oscillation.Science,228, 1084–1087.
Cane, M. A., 1986: El Nino.Annu. Rev. Earth Planet Sci.,14, 43–70.
Cane, M. A., Munnich, M., Zebiak, S. E., 1990: A study of self-excited oscillations of a tropical ocean-atmosphere system, part I: linear analysis.J. Atmos. Sci.,47, 1562–1577.
Chao, J., Zhang, R. 1988: The air-sea interaction waves in the tropics and their instabilities.Acta Meteor. Sinica,2, 275–287.
Deser, C., Wallace, J. M., 1990: Large-scale atmospheric circulation features of warm and cold episodes in the tropical Pacific.J. Climate,3, 1254–1281.
Gill, A. E., 1980: Some simple solutions for heat induced tropical circulation.Quart. J. Roy. Meteor. Soc.,106, 447–462.
Gill, A. E., Rasmusson, E. M., 1983: The 1982–1983 climate anomaly in the equatorial Pacific.Nature,306, 229–234.
Gill, A. E., 1985: Element of coupled ocean-atmosphere models. In: Nihoul, J. C. J. (ed.)Coupled Ocean-Atmosphere Models. (Elservier Oceanography Series, 40) pp. 303–327.
Hellerman, S., 1968: An updated estimate of the wind stress on the world ocean.Mon. Wea. Rev.,96, 63–74.
Hirst, A. C., 1985: Free equatorial instabilities in simple ocean-atmosphere models. In: Niboul, J. C. J. (ed.),Coupled Ocean-Atmosphere Models. (Elsevier Oceanography Series, 40) pp. 153–165.
Hirst, A. C. 1986: Unstable and damped equatorial modes in simple coupled ocean-atmosphere models.J. Atmos. Sci.,43, 606–630.
Hirst, A. C. 1988: Slow instabilities in tropical ocean basinglobal atmosphere models.J. Atmos. Sci.,45, 830–852.
Hirst, A. C., 1990: On simple coupled ocean-atmosphere models, equatorial instabilities and ENSO.Proc. Int TOGA Scientific Conference, WMO/TD, No. 379, WCRP-43, Geneva.
Lau, K. M., Sheu, P., 1988: Annual cycle, QBO, and Southern Oscillation in global precipitation.J. Geophys. Res.,93(D9), 10975–10988.
Meehl, G. A. 1987: The annual cycle and interannual variability in the tropical Pacific and Indian Ocean regions.Mon. Wea. Rev.,115 27–50.
Meehl, G. A., 1990: Seasonal cycle forcing of El Nino-Southern Oscillation in a global coupled ocean-atmosphere model.J. Climate,3, 72–98.
Neelin, J. D. 1990: A hybrid coupled general circulation model for El Nino studies.J. Atmos. Sci.,47, 674–693.
Neelin, J. D. 1991: The slow sea surface temperature mode and the fast-wave limit: Analytic theory for tropical interannual oscillations and experiments in a hybrid coupled model.J. Atmos. Sci. 48, 584–606.
Neelin, J. D. et al., 1992: Tropical air-sea interaction in general circulation models.Climate Dynamics,7, 73–104.
Philander, S. G., Yamagata, T., Pacanowski, R. C., 1984: Unstable air-sea interactions in the tropics.J. Atmos. Sci.,41, 604–613.
Philander, S. G., Pacanowski, R. C., Lau, N.-C., Nath, M. J., 1992: Simulation of ENSO with a global atmospheric GCM coupled to a high-resolution, tropical Pacific ocean GCM.J. Climate,5, 308–329.
Rasmusson, E. M., Carpenter, T. H. 1982: Variations in the tropical sea surface temperature and surface wind fields associated with the Southern Oscillation/El Nino.Mon. Wea. Rev.,110, 354–384.
Rasmusson, E. M., Wang, X., Ropelewski, C. 1990: The biennial component of ENSO variability.J. Mar. Sci.,1, 71–96.
Ropelewski, C. F., Halpert, M. S., Wang, X., 1992: Observed tropospheric biennial variability and its relationship to the Southern Oscillation.J. Climate,5, 594–614.
Schopf, P. S., Suarez, M. J., 1988: Vacillations in a coupled ocean-atmosphere model.J. Atmos. Sci.,45, 549–566.
Suarez, M. J., Schopf, P. S. 1988: A delayed action oscillator for ENSO.J. Atmos. Sci. 45, 3282–3287.
Yamagata, T., 1985: Stability of a simple coupled model in the tropics. In: (ed.) J. C. J., Nihoul,Coupled Ocean-Atmosphere Models. (Elsevier Oceanography Series, 40) 637–657.
Yang, X.-Q., Huang, S.-S., 1993: A study of dynamical features of air-sea coupling waves in the tropics.Acta Oceanologica Sinica,12, 379–394.
Yang, X.-Q., 1993: Numerical studies of ENSO dynamical processes. Ph.D. Thesis, Nanjing University, 235 pp.
Zebiak, S. E., Cane, M. A., 1987: A model El Nino-Southern Oscillation.Mon. Wea. Rev.,115, 2262–2279.
Zebiak, S. E., 1990: Intermediate models of ENSO. Proc. Int TOGA Scientific Conference, WMO/TD, No. 379,WCRP-43, Geneva.
Author information
Authors and Affiliations
Additional information
With 16 Figures
Rights and permissions
About this article
Cite this article
Yang, X.Q., Xie, Q., Ni, Y.Q. et al. ENSO cycle in a coupled ocean-atmosphere model and its negative feedback mechanism. Meteorl. Atmos. Phys. 61, 153–186 (1996). https://doi.org/10.1007/BF01025703
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01025703