[MITgcm-devel] verification experiment seaice_obcs

[Martin Losch]

Hi Dimitris,

thanks for reminding me. I noticed now that the IO is all single  
precision, could that be a reason for the sensitivity between platforms?

I remember that there was a restart problem with seaice, but as far as  
I remember it is related to EVP:  we need to store sigma12, but sigma  
12 is defined on Z-points, so we'd need the field (1:nx+1,1:ny+1), but  
there's no simple way of creating a pickup file like this (except via  
netcdf). For the LSR solver there was no problem and there isn't any  
problem in lab_sea with EVP, because we fixed the topography, see here:
<http://dev.mitgcm.org/cgi-bin/viewcvs.cgi/MITgcm/verification/lab_sea/input.hb87/?only_with_tag=MAIN 
 >
with this text
"lat-long grid & no-slip BC in seaice-dynamics produce different  
sigma12 at j=1 & j=Ny+1 : this case is not treated correctly in  
restart process. Fixed here by closing the domain at the Northern  
boundary."

Martin

On Feb 25, 2009, at 6:04 PM, Dimitris Menemenlis wrote:

> Hi Martin, there is an old thread that discussed the very same problem
> http://forge.csail.mit.edu/pipermail/mitgcm-devel/2008-April/003346.html
> but I never got around to resolving the issue.
>
> There is a suggestion that the restart issue has to do with edge,  
> see item
> 3 in the second list of message above.
>
> Another possibly-related issue, again unresolved, is
> http://forge.csail.mit.edu/pipermail/mitgcm-devel/2008-May/003367.html
> which suggests some issues with exf_interp and edges.
>
> I am bringing these issues back up to the surface in part as a  
> reminder
> for me to do something about them, not to pass the buck, but if anyone
> has suggestions or ideas, please let me know.
>
> D.
>
> On Feb 25, 2009, at 8:00 AM, Martin Losch wrote:
>
>> Hi there,
>>
>> I am trying to figure out, why I do not get perfect restarts with  
>> seaice. The lab_sea experiments all pass Jean-Michel fabulous 2+2=4  
>> test, but the seaice_obcs/run experiment doesn't. I don't see why  
>> this does not work, I have tried turning off all packages,  
>> including seaice, obcs, and what else could go wrong, but even the  
>> bare configuration without any package turned on does not pass this  
>> test. Does anyone have a clue what might be going wrong?
>>
>> Martin
>>
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