[MITgcm-support] Temperature Advection Scheme : Internal Gravity Wave Simulation

[Jody Klymak]

Hi Hanut,

On 26 Jun 2017, at 10:00, Hanut Vemulapalli wrote:

> Hi all,
>
> I am trying to simulate gravity waves produced by an isolated gaussian
> topography in a uniformly stratified ocean. I have a 2D simulation 
> with
> unit depth in the y-coordinate. I am applying the tidal forcing by
> prescribing the U-velocity at the boundaries (@Jody: Thank you for 
> your
> suggestions) . I am able to simulate gravity waves, but could anyone 
> please
> advice as to which temperature advection scheme would be best suited 
> for my
> case and to what extent the scheme used can effect the wave field 
> produced.
> I have tried using schemes 2,3,33 and 77 but there seems to be no
> difference in the wave field produced and the gravity wave beam is not
> sharp/poorly resolved.

Have a look at [Klymak et al 
2010](http://doi.org/10.1175/2010JPO4396.1)?  Beams won’t be sharp if 
there is a lot of turbulence near the tip of the topography.  Basically 
vertical modes with phase speed less than Um (where Um is the maximum 
speed at the crest of the sill) can’t escape in a tidal period and 
hence are dissipated.  This makes the beams fuzzy since they don’t 
have very much high-mode information any more (ie. no high vertical 
wavenumbers) (compare Fig 2a and 2b in that paper).

If you want sharper beams, turn your forcing velocity down.  They 
sharpen up quite well, though at some point the resolution in the model 
will limit their fidelity.

Cheers,   Jody

> Thanks in advance.
>
> Best regards,
> Hanut V
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