[MITgcm-devel] spurious vertical diffusion

[chris hill]

D.,

  Have you tried putting in a tracer that is horizontally uniform but 
that has a vertical profile? KPP will probably be doing something gross, 
so the background diffusivity may not be so relevant just below the ice.

Chris
Dimitris Menemenlis wrote:
> Alistair and Jean Michel, are any of your super-duper new 
> tracer-advection schemes ready for prime time on the cube?
> 
> In the Arctic domain of the 18-km cube configuration, there seems to be 
> too much vertical diffusion (or perhaps horizontal diffusion across 
> sloping isopycnals).  We have started an integration where the explicit 
> background vertical diffusion is much reduced (from 1.4e-5 to 1e-6 
> m^2/s) but that does not seem to impact the solutions very much.
> 
> Right now we use
> 
>  tempAdvScheme=33,
>  saltAdvScheme=33,
> 
> and we have zero explicit horizontal diffusivity.
> 
> Two specific questions:
> 
> 1) Is there a way to diagnose what is the effective vertical diffusivity 
> in the integration?
> 
> 2) Is there an advection scheme that will lead to less spurious vertical 
> diffusion than flux-limited DST3?
> 
> Dimitris
> 
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