The Oceanic Eddy Heat Transport

The rectified eddy heat transport is calculated from a global high-resolution ocean general circulation model. The eddy heat transport is found to be strong in the western boundary currents, the Antarctic Circumpolar Current, and the equatorial region. It is generally weak in the central gyres. It is also found to be largely confined to the upper 1000 m of the ocean model. The eddy heat transport is separated into its rotational and divergent components. The rotational component of the eddy heat transport is strong in the western boundary currents, while the divergent component is strongest in the equatorial region and Antarctic Circumpolar Current. In the equatorial region, the eddy heat transport is due to tropical instability waves, while in the western boundary currents and the Antarctic Circumpolar Current the large eddy heat transports arise from the meandering of the currents. Stammer’s method for estimating the eddy heat transport from an eddy diffusivity derived from mixing length arguments, using altimetry data and the climatological temperature field, is tested and fails to reproduce the model’s directly evaluated eddy heat transport in the equatorial regions, and possible reasons for the discrepancy are explored. However, in the Antarctic Circumpolar Current region and to a lesser extent in the western boundary currents, the model’s eddy heat transport is shown to have some qualitative agreement with his estimate.

[1]  M. Cox.  Generation and Propagation of 30-Day Waves in a Numerical Model of the Pacific , 1980 .

[2]  Frank O. Bryan,et al.  An Overlooked Problem in Model Simulations of the Thermohaline Circulation and Heat Transport in the Atlantic Ocean , 1995 .

[3]  Tropical instability wave kinematics: Observations from the Tropical Instability Wave Experiment , 1995 .

[4]  A. Bower,et al.  Structure of the Gulf Stream and Its Recirculations at 55°W , 1996 .

[5]  H. Bryden,et al.  Energetic eddies at the Northern edge of the Antarctic circumpolar current in the Southwest Pacific , 1985 .

[6]  M. Cox.  An Eddy Resolving Numerical Model of the Ventilated Thermocline , 1985 .

[7]  S. Gorshkov,et al.  World ocean atlas , 1976 .

[8]  R. Chervin,et al.  Transports and budgets of volume, heat, and salt from a global eddy-resolving ocean model , 1994 .

[9]  P. Kushner,et al.  A test, using atmospheric data, of a method for estimating oceanic eddy diffusivity , 1998 .

[10]  M. Spall,et al.  Specification of eddy transfer coefficients in coarse resolution ocean circulation models , 1997 .

[11]  Greg Holloway,et al.  Representing topographic stress for large-scale ocean models , 1992 .

[12]  M. Levine,et al.  The advective flux of heat by mean geostrophic motions in the Southern Ocean , 1981 .

[13]  Carl Wunsch,et al.  Where do ocean eddy heat fluxes matter , 1999 .

[14]  Robert M. Chervin,et al.  Ocean general circulation from a global eddy‐resolving model , 1992 .

[15]  B. Warren.  Approximating the energy transport across oceanic sections , 1999 .

[16]  Aike Beckmann,et al.  Effects of increased horizontal resolution in a simulation of the North Atlantic Ocean , 1994 .

[17]  M. Cox,et al.  Particle Dispersion and Mixing of Conservative Properties in an Eddy-Resolving Model , 1988 .

[18]  Carl Wunsch,et al.  An estimate of global ocean circulation and heat fluxes , 1996, Nature.

[19]  H. Hurlburt,et al.  Impact of Upper Ocean–Topographical Coupling and Isopycnal Outcropping in Japan/East Sea Models with 1/8° to 1/64° Resolution , 2000 .

[20]  W. Pichel,et al.  Equatorial Long Waves in Geostationary Satellite Observations and in a Multichannel Sea Surface Temperature Analysis , 1983 .

[21]  S. Rintoul,et al.  Eddy Variability and Energetics from Direct Current Measurements in the Antarctic Circumpolar Current South of Australia , 2000 .

[22]  J. Marshall,et al.  A Note on Rotational and Divergent Eddy Fluxes , 1981 .

[23]  P. Niiler,et al.  Effects of instability waves in the mixed layer of the equatorial Pacific , 1997 .

[24]  Harry L. Bryden,et al.  Direct estimates and mechanisms of ocean heat transport , 1982 .

[25]  M. Cronin,et al.  Eddy–Mean Flow Interaction in the Gulf Stream at 68°W. Part I: Eddy Energetics , 1996 .

[26]  Frank J. Wentz,et al.  Satellite microwave SST observations of transequatorial tropical instability waves , 2000 .

[27]  J. Willebrand,et al.  Parameterization of Mesoscale Eddies as Inferred from a High-Resolution Circulation Model , 1996 .

[28]  N. Hogg.  Observations of Gulf Stream Meander-Induced Disturbances , 1994 .

[29]  R. Pacanowski,et al.  The mass and heat budget in a model of the tropical Atlantic Ocean , 1986 .

[30]  S. Thompson.  Estimation of the Transport of Heat in the Southern Ocean Using a Fine-Resolution Numerical Model , 1993 .

[31]  H. Bryden,et al.  POLEWARD HEAT FLUX AND CONVERSION OF AVAILABLE POTENTIAL ENERGY IN DRAKE PASSAGE , 1979 .

[32]  Stephen M. Griffies,et al.  The Gent–McWilliams Skew Flux , 1998 .

[33]  D. Hansen,et al.  Genesis and effects of long waves in the equatorial Pacific , 1984 .

[34]  P. Gent,et al.  Isopycnal mixing in ocean circulation models , 1990 .

[35]  M. Maltrud,et al.  Numerical simulation of the North Atlantic Ocean at 1/10 degrees , 2000 .

[36]  W. R. Holland,et al.  Numerical Simulation of Equatorial Ocean Circulation. Part I: A Basic Case in Turbulent Equilibrium , 1980 .

[37]  J. Green,et al.  Transfer properties of the large‐scale eddies and the general circulation of the atmosphere , 1970 .

[38]  J. McClean,et al.  Comparisons of mesoscale variability in the Semtner‐Chervin 1/4° model, the Los Alamos Parallel Ocean Program 1/6° model, and TOPEX/POSEIDON data , 1997 .

[39]  S. Worley,et al.  Methods for making point estimates of eddy heat flux as applied to the Antarctic Circumpolar Current , 1985 .

[40]  G. Danabasoglu,et al.  The Role of Mesoscale Tracer Transports in the Global Ocean Circulation , 1994, Science.

[41]  Tong Lee,et al.  Seasonal Cycles of Meridional Overturning and Heat Transport of the Indian Ocean , 1998 .

[42]  R. Legeckis.  Long Waves in the Eastern Equatorial Pacific Ocean: A View from a Geostationary Satellite , 1977, Science.

[43]  J. Marotzke,et al.  The dynamics of ocean heat transport variability , 2001 .

[44]  H. Bryden,et al.  Eddy momentum and heat fluxes and their effects on the circulation of the equatorial Pacific Ocean , 1989 .

[45]  D. Stammer.  On Eddy Characteristics, Eddy Transports, and Mean Flow Properties , 1998 .

[46]  C. Wunsch,et al.  How well does a 1/4° global circulation model simulate large-scale oceanic observations? , 1996 .