[MITgcm-devel] background diffKr in vertical mixing pkgs

[Jean-Michel Campin]

Hi All,

I did not (yet) get much feedback on this issue.
Does anyone care ?

Cheers,
Jean-Michel

On Fri, Nov 14, 2014 at 09:32:41AM -0500, Jean-Michel Campin wrote:
> Hi,
> 
> Regarding the background value of vertical diffusivity in pkgs:
> ggl90, kl10, my82, pp81,
> we currently use the temperature diffusivity (diffKrNrT)
> but regarding ptracers default diffusivity (and default 3-D field diffKr), 
> we use the salinity one.
> 
> I am thinking of few changes:
> 1) It would be more consistent to change the background value in 
>    these vertical mixing schemes from diffKrNrT to diffKrNrS.
> 2) In addition, in the case where no vertical diffusivity for salinity is specified,
>    we could change the code to use the temperature diffusivity profile 
>    instead of diffKrSDefault. 
>    This way, if salinity is not stepped forward (only 1 tracer), the temp. 
>    diffusivity would be used as a default.
> 
> 3) Regarding the implemetation of ALLOW_3D_DIFFKR in pkgs kl10, my82 & pp81
>    I have the impression that the 3-D field (diffKr) is, at the end, not used
>    at all (added and then substracted). Will fix this part by using
>    the 3-D field diffKr as a minimum value in kl10_calc.F, my82_calc.F & pp81_calc.F
> 4) But in pkg ggl90 (where the background value can affect the vertical
>    diffusion of TKE), I am not sure what should be done with ALLOW_3D_DIFFKR:
>    continue to use diffKrNrT (or diffKrNrS) as the background ?
>    or decide to use the 3-D diffKr instead ?
> 
> Comments and advise are welcome.
> 
> Cheers,
> Jean-Michel
> 
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