We would like to thank the many denizens of the Climate Palace for their support during the years of research that lead to this paper. We also thank Cecile Penland and two anonymous reviewers for many helpful comments on the original manuscript. This work has been supported by a grant from the NOAA Office of Global Programs to the Hayes Center at the University of Washington.
Barnett, T. P., M. Latif, N. Graham, M. Flugel, S. Pazan, and W. White, 1993: ENSO and ENSO-related predictability. Part I: Prediction of equatorial Pacific sea surface temperature with a hybrid coupled ocean–atmosphere model. J. Climate,6, 1545–1566.
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.
——, and A. C. Hirst, 1989: Interannual variability in the tropical atmosphere–ocean system: Influence of the basic state, ocean geometry, and nonlinearity. J. Atmos. Sci.,46, 1687–1712.
Burgers, G., 1999: The El Niño stochastic oscillator. Climate Dyn.,15, 521–531.
Chang, P., L. Ji, H. Li, and M. Flugel, 1996: Chaotic dynamic versus stochastic processes in ENSO in coupled ocean–atmosphere models. Physica D,9, 301–320.
Chen, Y.-Q., D. S. Battisti, T. N. Palmer, J. Barsugli, and E. S. Sarachik, 1997: A study of the predictability of tropical Pacific SST in a coupled atmosphere–ocean model using singular vector analysis: The role of the annual cycle and the ENSO cycle. Mon. Wea. Rev.,125, 831–845.
Clarke, A. J., 1991: On the reflection and transmission of low-frequency energy at the irregular western Pacific Ocean boundary. J. Geophys. Res.,96, 3289–3305.
du Penhoat, Y., and M. A. Cane, 1991: Effects of low-latitude western boundary gaps on the reflection of equatorial motions. J. Geophys. Res.,96, 3307–3322.
Eckert, C., and M. Latif, 1997: Predictabilty of a stochastically forced hybrid coupled model of El Niño. J. Climate,10, 1488–1504.
Farrell, B., 1988a: Optimal excitation of perturbations in viscous shear flow. Phys. Fluids,31, 2093–2102.
——, 1988b: Optimal excitation of neutral Rossby waves. J. Atmos. Sci.,45, 163–172.
Flugel, M., and P. Chang, 1999: Stochastically induced climate shift of El Nino–Southern Oscillation. Geophys. Res. Lett.,26, 2473–2476.
Gill, A. E., 1980: Some simple solutions for heat-induced tropical circulation. Quart. J. Roy. Meteor. Soc.,106, 447–462.
Hirst, A. C., 1988: Slow instabilities in tropical ocean basin–global atmosphere models. J. Atmos. Sci.,45, 830–852.
Iooss, G., and D. D. Joseph, 1980: Elementary Stability and Bifurcation Theory. Springer-Verlag, 286 pp.
Jin, F., D. Neelin, and M. Ghil, 1994: El Niño on the devil’s staircase:Annual subharmonic steps to chaos. Science,264, 70–72.
Kleeman, R., 1993: On the dependence of hindcast skill on ocean thermodynamics in a coupled ocean–atmosphere model. J. Climate,6, 2012–2033.
Lindzen, R., and S. Nigam, 1987: On the role of sea surface temperature gradients in forcing low-level winds and convergence in the Tropics. J. Atmos. Sci.,44, 2440–2458.
Mantua, N. J., and D. S. Battisti, 1994: Evidence for the delayed oscillator mechanism for ENSO: The “observed” oceanic Kelvin mode in the western Pacific. J. Phys. Oceanogr.,24, 691–699.
Moore, A. M., and R. Kleeman, 1999: Stochastic forcing of ENSO by the intraseasonal oscillation. J. Climate,12, 1199–1220.
Noble, B., and J. W. Daniel, 1988: Applied Linear Algebra. 3d ed. Prentice-Hall.
Palmer, T. N., R. Gelaro, J. Barkmeijer, and R. Buizza, 1998: Singular vectors, metrics, and adaptive observations. J. Atmos. Sci.,55, 633–653.
Penland, C., and P. D. Sardeshmuhk, 1995: The optimal growth of tropical sea surface temperature anomalies. J. Climate,8, 1999–2004.
Picaut, J., C. Menkes, J.-P. Boulanger, and Y. du Penhout, 1993: Dissipation in a Pacific equatorial long wave model. TOGA Notes,10, 11–15.
Rasmusson, E. M., and T. H. Carpenter, 1982: Variations in tropical sea surface temperatures and surface wind fields associated with the Southern Oscillation and El Niño. Mon. Wea. Rev.,110, 354–384.
Thompson, C. J., 1998a: Initial conditions for optimal growth in a coupled ocean–atmosphere model of ENSO. J. Atmos. Sci.,55, 537–557.
——, 1998b: A linear, stochastic, dynamical model of El Niño/Southern Oscillation. Ph.D. thesis, University of Washington, 235 pp.
Tziperman, E., L. Stone, M. Cane, and H. Jarosh, 1994: El Niño chaos: Overlapping of resonances between the seasonal cycle and the Pacific ocean–atmosphere oscillator. Science,264, 72–74.
Wang, B., A. Barcilon, and Z. Fang, 1999: Stochastic dynamics of El Niño–Southern Oscillation. J. Atmos. Sci.,56, 5–23.
Xue, Y., M. A. Cane, and S. E. Zebiak, 1997a: Predictability of a coupled model of ENSO using singular vector analysis. Part I: Optimal growth in seasonal background and ENSO cycles. Mon. Wea. Rev.,125, 2043–2056.
——, ——, ——, and T. N. Palmer, 1997b: Predictability of a coupled model of ENSO using singular vector analysis. Part II: Optimal growth and forecast skill. Mon. Wea. Rev.,125, 2057–2073.
Zebiak, S. E., 1984: Tropical atmospheric–ocean interaction and the El Niño/Southern Oscillation phenomenon. Ph.D. thesis, MIT, 261 pp. [Available from MIT, 77 Massachusetts Avenue, Cambridge, MA 02139-4307.].
——, 1986: Atmospheric convergence feedback in a simple model for El Niño. Mon. Wea. Rev.,114, 1263–1271.
——, and M. A. Cane, 1987: A model ENSO. Mon. Wea. Rev.,115, 2262–2278.