[MITgcm-devel] obcs_seaice_sponge.F

[Jean-Michel Campin]

Hi Dimitris,

Yes, this is part of the long list of issues with OBCS SPONGE.
And by the way, I think it would be better not to turn on the sponge 
for oceanic fields when you add this to exp seice_obcs, because regarding
velocity (as you mentionned) there are other issues.

Jean-Michel

On Thu, Sep 20, 2012 at 05:45:58PM +0000, Menemenlis, Dimitris (3248) wrote:
> Jean-Michel and Patrick, I know that it is no longer actively supported but, for the record, there
> seems to be a problem with obcs_sponge.F, and it dates back to very first check in 10+ years ago.
> 
> According to comments, the relaxation time scale is supposed to be linear
> and controlled by U/Vrelaxobcsinner/bound:
> 
> C U/Vrelaxobcsinner/bound :: relaxation time scale (in seconds) on the boundary
> C                            (bound) and at the innermost grid point of the sponge
> C                            layer (inner); relaxation time scales in-between
> C                            are linearly interpolated from these values
> 
> But as coded, the relaxation is quadratic because there is an additional attenuation term due
> to linearly decreasing u/v/t/srelax as it goes away from the boundary.
> 
> Additionally, as coded, relaxation will be zero if spongeThickness = 1.
> 
> I will fix these two problems in obcs_seaice_sponge.F before checking in,
> 
> Let me know if you want me to do anything about these two problem in obcs_sponge.F
> 
> Cheers
> 
> Dimitris Menemenlis
> 
> 
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