Theoretical Climate Dynamics - Coupled Atmosphere-Ocean System

Atmosphere-ocean interactions are an important factor in the Earth's climate system. They take place on a wide range of spatial and temporal scales.

"Toward a Theory of the North Atlantic Oscillation", AOS Seminar by M. Ghi

In the tropical Pacific, the interaction leads to the well-known El Niño / Southern Oscillation (ENSO) phenomenon, whose behavior exhibits both regular and irregular aspects. We study this highly nonlinear atmosphere-ocean system in terms of observations, theories, and models; estimate the coupling parameters; and carry out experimental forecasts.

For more details of the phenomenon, please see NOAA El Niño Theme page.

SSA-MEM Forecast of Niño-3

ENSO Empirical Model Reduction and Forecast

ENSO and the seasonal cycle

Modeling ENSO has a long history (Philander, 1990; Neelin et al., 1994). Introducing seasonal variability into the Neelin-Jin model (Jin and Neelin, 1993; Neelin and Jin, 1993) helps one understand both ENSO's regularity (locking of warm events to boreal winter) and irregularity (occurrence of major warmings every 1--10 years). Rich variability arises from the interaction of the seasonal forcing and an intrinsic ocean-atmosphere instability, present already in annually averaged models. Dynamical systems theory provides powerful tools to help understand the system's governing mechanisms and parameter dependence. In the figure, regimes of subharmonic, frequency-locked, and chaotic solutions are shown in the plane of the coupling parameter and a subsurface flow parameter that determines the model's intrinsic ENSO period. Blank areas represent regions where no interannual signal is present. Color scale represents the frequency ratio of the interannual oscillation to the annual cycle in regimes that are frequency locked; e.g., 0.22 indicates two ENSO cycles every nine years. Chaotic regimes are indicated in grey, regardless of what spectral peaks emerge from their broad spectral background figure (from Jin et al., 1996).

TCD Members:

M. Ghil, D. Kondrashov, S. Kravtsov.

Collaborator at UCLA:

J.D. Neelin.

References:

Climate Research Committee (E. J. Barron, D. S. Battisti, B. A. Boville, K. Bryan, G. F. Carrier, R. D. Cess, R. E. Davis, M. Ghil, M. M. Hall, T. R. Karl, J. T. Kiehl, D. G. Martinson, C. L. Parkinson, B. Saltzman, R. P. Turco), 1994: Global Ocean-Atmosphere- Land System (GOALS) for Predicting Seasonal-to-Interannual Climate, National Academy Press, Washington, D.C., 103 pp.

Ghil, M. and N. Jiang, 1998: Recent forecast skill for the El Niño/Southern Oscillation. Geophy. Rev. Lett., 25, 171-174.

Ghil, M., and A. W. Robertson, 2000: Solving problems with GCMs: General circulation models and their role in the climate modeling hierarchy. General Circulation Model Development: Past, Present and Future, D. Randall (Ed.), Academic Press, San Diego, pp. 285-325.

Hao, Z., and M. Ghil, 1994: Data assimilation in a simple tropical ocean model with wind-stress errors, J. Phys. Oceanogr., 24, 2111-2128.

Hao, Z., and M. Ghil, 1995: Sequential parameter estimation for a coupled ocean-atmosphere model. In Proc. 2nd WMO Int'l Symp. on Assim. of Obs. in Meteor. & Oceanogr., Tokyo, March 1995, WMO/TD-No. 651, PWPR Report Series No. 5, WMO Geneva, Switzerland, Vol. I, pp. 181-186.

Jiang, N., D. Neelin and M. Ghil, 1995: Quasi-quadrennial and quasi-biennial variability in the equatorial Pacific. Clim. Dyn., 12, 101-112.

Jiang, N., M. Ghil and D. Neelin, 1995-1997: Forecasts of Nino-3 SST anomalies and SOI based on singular spectrum analysis combined with the maximum entropy method. Experimental Long-Lead Forecast Bulletin , Vol. 4, No. 4, 42-43, to Vol. 6, Nos. 1 & 2, National Centers for Environmental Prediction, NOAA, U.S. Department of Commerce.

Jin, F.-f., and J. D. Neelin, 1993: Modes of interannual tropical ocean-atmosphere interaction - a unified view. Part I: numerical results. J. Atmos. Sci., 50, 3477-3503.

Jin, F.-f., J. D. Neelin and M. Ghil, 1994: El Niño on the Devil's Staircase: Annual subharmonic steps to chaos, Science, 264, 70-72.

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.

Keppenne, C. L. and M. Ghil, 1992-1995: Forecasts of the Southern Oscillation Index Using Singular Spectrum Analysis and the Maximum Entropy Method. Experimental Long-Lead Forecast Bulletin, Vol. 1, Nos. 1-4, Vol. 2, Nos. 1-4, Vol. 3, Nos. 1-4, and Vol. 4, Nos. 1 & 2, National Meteorological Center, NOAA, U.S. Department of Commerce.

Kondrashov, D., M. Ghil, and D. Neelin, 2002-present: Forecasts of Nino-3 SST anomalies and SOI based on singular spectrum analysis combined with the maximum entropy method, Experimental Long-Lead Forecast Bulletin, Vol. 11, No. 1, pp. xx-yy; quarterly issues published also electronically, http://grads.iges.org/ellfb.

Neelin, J. D. and F.-f. Jin, 1993: Modes of interannual tropical ocean-atmosphere interaction - a unified view. Part II: Analytical results in the weak-coupling limit. J. Atmos. Sci., 50, 3504-3522.

Neelin, J. D., M. Latif, and F.-f. Jin, 1994: Dynamics of coupled ocean-atmosphere models: the tropical problem. Ann. Rev. Fluid Mech., 26, 617-659.

Neelin, J. D., M. Latif, M. A. F. Allaart, M. A. Cane, U. Cubasch, W. L. Gates, P. R. Gent, M. Ghil, C. Gordon, N. C. Lau, C. R. Mechoso, G. A. Meehl, J. M. Oberhuber, S. G. H. Philander, P. S. Schopf, K. R. Sperber, A. Sterl, T. Tokioka, J. Tribbia, and S. E. Zebiak, 1992: Tropical air-sea interaction in general circulation models, Climate Dyn., 7, 73-104.

Philander, S. G. H., 1990: El Niño, La Niña and the Southern Oscillation. Academic Press, San Diego, 293 pp.

Robertson, A. W., C.-C. Ma, C. R. Mechoso, and M. Ghil, 1995a: Simulation of the Tropical-Pacific climate with a coupled ocean-atmosphere general circulation model. Part I: The seasonal cycle, J. Climate, 8, 1178-1198.

Robertson, A. W., C.-C. Ma, M. Ghil, and C. R. Mechoso, 1995b: Simulation of the Tropical-Pacific climate with a coupled ocean-atmosphere general circulation model. Part II: Interannual variability, J. Climate, 8, 1199-1216.

Saunders, A., M. Ghil, and D. Neelin, 1997-2001: Forecasts of Niño SST anomalies and SOI based on singular spectrum analysis combined with the maximum entropy method, Experimental Long-Lead Forecast Bulletin, Vol. 6, No. 3, pp. 43-44; subsequent quarterly issues published also electronically, http://grads.iges.org/ellfb.

Sun, C., Z. Hao, M. Ghil, and J. D. Neelin, 2002: Data assimilation for a coupled ocean-atmosphere model. Part I: Sequential state estimation, Mon. Wea. Rev., 130, 1073-1099.

Unal, Y. S., and M. Ghil, 1995: Interannual and interdecadal oscillation patterns in sea level, Climate Dyn., 11, 255-278.

TCD Members:
	M. Ghil, D. Kondrashov, S. Kravtsov.
Collaborator at UCLA:
	J.D. Neelin.
References:
	Climate Research Committee (E. J. Barron, D. S. Battisti, B. A. Boville, K. Bryan, G. F. Carrier, R. D. Cess, R. E. Davis, M. Ghil, M. M. Hall, T. R. Karl, J. T. Kiehl, D. G. Martinson, C. L. Parkinson, B. Saltzman, R. P. Turco), 1994: Global Ocean-Atmosphere- Land System (GOALS) for Predicting Seasonal-to-Interannual Climate, National Academy Press, Washington, D.C., 103 pp.
	Ghil, M. and N. Jiang, 1998: Recent forecast skill for the El Niño/Southern Oscillation. Geophy. Rev. Lett., 25, 171-174.
	Ghil, M., and A. W. Robertson, 2000: Solving problems with GCMs: General circulation models and their role in the climate modeling hierarchy. General Circulation Model Development: Past, Present and Future, D. Randall (Ed.), Academic Press, San Diego, pp. 285-325.
	Hao, Z., and M. Ghil, 1994: Data assimilation in a simple tropical ocean model with wind-stress errors, J. Phys. Oceanogr., 24, 2111-2128.
	Hao, Z., and M. Ghil, 1995: Sequential parameter estimation for a coupled ocean-atmosphere model. In Proc. 2nd WMO Int'l Symp. on Assim. of Obs. in Meteor. & Oceanogr., Tokyo, March 1995, WMO/TD-No. 651, PWPR Report Series No. 5, WMO Geneva, Switzerland, Vol. I, pp. 181-186.
	Jiang, N., D. Neelin and M. Ghil, 1995: Quasi-quadrennial and quasi-biennial variability in the equatorial Pacific. Clim. Dyn., 12, 101-112.
	Jiang, N., M. Ghil and D. Neelin, 1995-1997: Forecasts of Nino-3 SST anomalies and SOI based on singular spectrum analysis combined with the maximum entropy method. Experimental Long-Lead Forecast Bulletin , Vol. 4, No. 4, 42-43, to Vol. 6, Nos. 1 & 2, National Centers for Environmental Prediction, NOAA, U.S. Department of Commerce.
	Jin, F.-f., and J. D. Neelin, 1993: Modes of interannual tropical ocean-atmosphere interaction - a unified view. Part I: numerical results. J. Atmos. Sci., 50, 3477-3503.
	Jin, F.-f., J. D. Neelin and M. Ghil, 1994: El Niño on the Devil's Staircase: Annual subharmonic steps to chaos, Science, 264, 70-72.
	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.
	Keppenne, C. L. and M. Ghil, 1992-1995: Forecasts of the Southern Oscillation Index Using Singular Spectrum Analysis and the Maximum Entropy Method. Experimental Long-Lead Forecast Bulletin, Vol. 1, Nos. 1-4, Vol. 2, Nos. 1-4, Vol. 3, Nos. 1-4, and Vol. 4, Nos. 1 & 2, National Meteorological Center, NOAA, U.S. Department of Commerce.
	Kondrashov, D., M. Ghil, and D. Neelin, 2002-present: Forecasts of Nino-3 SST anomalies and SOI based on singular spectrum analysis combined with the maximum entropy method, Experimental Long-Lead Forecast Bulletin, Vol. 11, No. 1, pp. xx-yy; quarterly issues published also electronically, http://grads.iges.org/ellfb.
	Neelin, J. D. and F.-f. Jin, 1993: Modes of interannual tropical ocean-atmosphere interaction - a unified view. Part II: Analytical results in the weak-coupling limit. J. Atmos. Sci., 50, 3504-3522.
	Neelin, J. D., M. Latif, and F.-f. Jin, 1994: Dynamics of coupled ocean-atmosphere models: the tropical problem. Ann. Rev. Fluid Mech., 26, 617-659.
	Neelin, J. D., M. Latif, M. A. F. Allaart, M. A. Cane, U. Cubasch, W. L. Gates, P. R. Gent, M. Ghil, C. Gordon, N. C. Lau, C. R. Mechoso, G. A. Meehl, J. M. Oberhuber, S. G. H. Philander, P. S. Schopf, K. R. Sperber, A. Sterl, T. Tokioka, J. Tribbia, and S. E. Zebiak, 1992: Tropical air-sea interaction in general circulation models, Climate Dyn., 7, 73-104.
	Philander, S. G. H., 1990: El Niño, La Niña and the Southern Oscillation. Academic Press, San Diego, 293 pp.
	Robertson, A. W., C.-C. Ma, C. R. Mechoso, and M. Ghil, 1995a: Simulation of the Tropical-Pacific climate with a coupled ocean-atmosphere general circulation model. Part I: The seasonal cycle, J. Climate, 8, 1178-1198.
	Robertson, A. W., C.-C. Ma, M. Ghil, and C. R. Mechoso, 1995b: Simulation of the Tropical-Pacific climate with a coupled ocean-atmosphere general circulation model. Part II: Interannual variability, J. Climate, 8, 1199-1216.
	Saunders, A., M. Ghil, and D. Neelin, 1997-2001: Forecasts of Niño SST anomalies and SOI based on singular spectrum analysis combined with the maximum entropy method, Experimental Long-Lead Forecast Bulletin, Vol. 6, No. 3, pp. 43-44; subsequent quarterly issues published also electronically, http://grads.iges.org/ellfb.
	Sun, C., Z. Hao, M. Ghil, and J. D. Neelin, 2002: Data assimilation for a coupled ocean-atmosphere model. Part I: Sequential state estimation, Mon. Wea. Rev., 130, 1073-1099.
	Unal, Y. S., and M. Ghil, 1995: Interannual and interdecadal oscillation patterns in sea level, Climate Dyn., 11, 255-278.