Parameterization of Eddy Effects on Mixed Layers and Tracer Transport: A Linearized Eddy Perspective

Two aspects of the effects of eddies on ocean circulation have proven difficult to parameterize: eddy effects in regions of neutrally stable (or convecting) fluid and the mixing of passive tracers. The effects of linearized eddies, although a restrictive parameter regime, can be straightforwardly computed in these cases. The eddy effects in areas of neutral stability—for example, mixed layers—blend naturally into those in the stably stratified water below, although losing the concept of bolus velocity. Instead, the mixed layer density is advected by an extra overturning velocity and is diffused laterally by a diffusion that is the same as the eddy diffusion at the top of the stably stratified fluid. Passive tracers are advected by the bolus velocity and mixed by the same diffusivity as is used to compute the bolus velocity at that location, so that two different diffusivities are not needed.

[1]  R. Ferrari,et al.  Transformed Eulerian-Mean Theory. Part I: Nonquasigeostrophic Theory for Eddies on a Zonal-Mean Flow , 2005 .

[2]  A. Nurser,et al.  Isopycnal Averaging at Constant Height. Part I: The Formulation and a Case Study , 2004 .

[3]  A. Nurser,et al.  Isopycnal averaging at constant height. Part II: relating to the residual streamfunction in eulerian space , 2004 .

[4]  P. Malanotte‐Rizzoli,et al.  Assessment of mesoscale eddy parameterizations for a single‐basin coarse‐resolution ocean model , 2002 .

[5]  T. McDougall,et al.  The Temporal-Residual-Mean Velocity. Part II: Isopycnal Interpretation and the Tracer and Momentum Equations , 2001 .

[6]  P. Killworth.  Boundary Conditions on Quasi-Stokes Velocities in Parameterizations , 2001 .

[7]  W. Hazeleger,et al.  Eddy mixing of potential vorticity versus thickness in an isopycnic ocean model , 2001 .

[8]  D. Marshall,et al.  On the validity of downgradient eddy closures in ocean models , 2000 .

[9]  T. Schneider,et al.  The Surface Branch of the Zonally Averaged Mass Transport Circulation in the Troposphere , 1999 .

[10]  Peter D. Killworth,et al.  On the parameterization of eddy transfer. Part I. Theory , 1997 .

[11]  John K. Dukowicz,et al.  Stochastic theory of compress-ible turbulent fluid transport , 1997 .

[12]  D. Marshall,et al.  On the eddy transfer of tracers : Advective or diffusive ? , 1997 .

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

[14]  P. Gent,et al.  Parameterizing eddy-induced tracer transports in ocean circulation models , 1995 .

[15]  W. Young.  The Subinertial Mixed Layer Approximation , 1994 .

[16]  C. Garrett,et al.  Mixed Layer Restratification Due to a Horizontal Density Gradient , 1994 .

[17]  A. Robinson,et al.  Time‐dependent topographic meandering , 1970 .

[18]  V. Canuto,et al.  Modeling mesoscale eddies , 2005 .

[19]  Richard G. Williams,et al.  Why Are Eddy Fluxes of Potential Vorticity Difficult to Parameterize , 2004 .

[20]  H. Hasumi,et al.  Developments in ocean climate modelling , 2000 .

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