[MITgcm-support] Re : Water at the bottom of NA below freezingpoint

[Dror Mirzayof]

Hi

How bad would it be if we force the ocean temperature to be above the 
freezing point (using useOldFreezing) ?
According to Martin this is like adding an additional heat source at the 
bottom. Is this approach appropriate ??

Dror


Martin Losch wrote:

> Just a quick comment for Jeff:
> On 8 Mar 2008, at 19:48, Jeff Scott wrote:
>
>> I've also tried different advection schemes (besides 2). 33 and 
>> especially 77 are not usable, as they radically affect the model's 
>> temperature structure, being rather diffuse. I've also tried the 
>> Prather/SOM
>
>
> When you use one of the multidimensional advection schemes (e.g., 33 
> or 77), make sure that you have "staggerTimeStep=.true.", otherwise 
> these scheme give very unexpected results during spinup. If you use 
> staggerTimeStep=.true., then advscheme 2 and 77 (which are both 2nd 
> order), give similar results in coarse resolution with much smaller 
> overshoots (according to my experience). As far as I remember, Dror is 
> using that kind of parameter combination, so his results are either 
> due to the very small but finite overshoots, that are still present in 
> 33 or 77, or something completely different.
>
> another comment on numerical diffusivity: Thomas Zweigle has carried 
> out a nice comparison of numerical diffusivities of the various 
> schemes in a very high resolution (DNS) simulation. Thomas, maybe you 
> can share a figure (a small jpeg or png please)?
>
> Martin
>
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