[MITgcm-support] OBC problem: spurious boundary jets with C-D coupling

[Mark Hadfield]

Thanks, Martin and Chris.

chris hill wrote:
> As Martin notes the code for CD with OBCS has not been written.
>  What resolution are you working at? Mostly CD is used for situations 
> where the deformation radius is not resolved i.e. resolutions > 25km. 
> For a limited area run it may not be needed. For resolutions where 
> eddy scale is resolved or at least things are eddy permitting then 
> sub-grid dissipation is more cleanly (although its still a dirty 
> business) handled by either fixed laplacian and biharmonic viscosities 
> or by the flow dependent smag/leith form (described in the online docs).
The simulation I am doing right now is at fairly coarse resolution (25 
km) and is diagnostic & linear, ie

      saltStepping = .FALSE.
      tempStepping = .FALSE.
      momStepping = .TRUE.
      momAdvection = .FALSE.

Simulations of this sort are prone to developing grid-scale noise, as I 
have found with ROMS, but biharmonic viscosity controls that nicely, 
thanks. Future, more realistic (I hope) simulations will use finer 
resolution and full dynamics.

The decision to start with the CD scheme enabled wasn't a decision, 
really, just inertia: I started with one of the verification experiments 
and started hacking.

-- 
Mark Hadfield          "Kei puwaha te tai nei, Hoea tahi tatou"
m.hadfield at niwa.co.nz
National Institute for Water and Atmospheric Research (NIWA)


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