[MITgcm-support] SOM problems

[Martin Losch]

Christopher,

some of the multidim-advection schemes require that you set  
StaggerTimeStep = .true., (in PARM01), to get results that are  
comparable to non-multidim advection scheme, e.g., when I switched  
from scheme 2 to scheme 33 I had to do that in order to not destroy  
my stratification. Maybe that's relevant for SOM as well ...

Martin

On 24 Jan 2008, at 03:12, Christopher L. Wolfe wrote:

>
> Hi modelers,
>
> Does anyone have any experience using Pather's second order moments  
> (advection scheme 81) with MITgcm?
>
> I've been trying to use it starting with a well-equilibrated run  
> using another advection scheme (using the U,V, Eta, and tracer  
> fields as initial/hydrography fields since SOM requires different  
> pickup information), but I'm getting really bizarre results. For  
> one, I'm finding SOM to be *extremely* diffusive: The advection  
> scheme is destroying tracer variance at twice the rate of diffusion  
> (which is relatively large at 8e-5 m^2/s). As a result, the  
> temperature field looks like one you would expect from a system  
> with much larger explicit diffusion: the temperature fields are  
> very smooth and the whole basin is becoming vertically unstratified.
>
> Has anyone used this advection scheme and gotten good results? Is  
> there anything I need to do with the configuration, other than set  
> the advection scheme to 81?
>
> Thanks,
> Christopher
>
> -----------------------------------------------------------
> Dr. Christopher L. Wolfe                   858-534-4560
> Physical Oceanography Research Division    OAR 357
> Scripps Institution of Oceanography, UCSD  clwolfe at ucsd.edu
> -----------------------------------------------------------
>
>
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