[MITgcm-devel] seaice growth

[Matthew Mazloff]

Hello,

Thanks for the help.  Turns out large HEFFs were largely just a red  
herring.  The problem seems to be primarily that I was using default  
DIFF1, and this changed from 0.004 to 0 along the line.  I finally  
payed attention to the STDERR warning, and added
       DIFF1             = .004,
in data.seaice.  My stability issues are now resolved!  But I have  
questions:

As you can see I am using the default advection scheme,   
SEAICEadvScheme    = 2, is this not recommended?  Perhaps I should  
just change my advection scheme to 33 or 77 -- I am not using seaice  
dynamics in the adjoint run.

Regardless, I'm not sure it is the best idea to have default  
parameters (SEAICEadvScheme    = 2, with DIFF1             = 0.0) that  
are not stable....perhaps the warning should be switched to a stop.

Thanks
Matt





On Aug 18, 2011, at 12:52 AM, Martin Losch wrote:

> Matt,
>
> what is "extreme"? I have runs where LSOR "handles" 30m of ice.  
> Theoretically, the ice strength must not become "nearly infinite",  
> because then the convergence of the iterative solver is bad. This is  
> achieved by limiting the ice strength/viscosity (not HEFF) and this  
> is described even in the documentation (o:
> The runtime variable for \Delta^*=SEAICE_zetaMaxFac=2.5e8, however,  
> that your can modify, is not described in the documentation,  
> probably, because I forgot it or I did not want it to be changed?
>
> I agree with Ian: Hack the code in seaice_dynsolver.F and leave  
> seaice_growth.F alone.
>
> I am a little surprised that the LSOR solver crashes. Since revision  
> 1.39 it has been remarkably stable.
>
> Martin
>
> On Jul 28, 2011, at 1:50 AM, Matthew Mazloff wrote:
>
>> Hi Jean-Michel,
>>
>> Ooops, sorry, missed it at the top there!
>>
>> OK, so I see now that #define SEAICE_CAP_HEFF in SEAICE_OPTIONS did  
>> nothing because capping HEFF is only allowed in LEGACY code.
>>
>> Are there any "hacks" that I can use in the new sea ice code to  
>> keep the model well conditioned and running.  I would like to  
>> diagnose how the ice is piling up, and not having it crash as soon  
>> as it starts to pile up would be nice
>>
>> Thanks,
>> Matt
>>
>>
>>
>>
>> On Jul 27, 2011, at 9:23 AM, Jean-Michel Campin wrote:
>>
>>> Hi Matt,
>>>
>>> I don't know which version of seaice_growth.F you are looking at,
>>> since:
>>>> #include "SEAICE_OPTIONS.h" ?
>>> has been there from the beginning (seaice_growth.F version 1.1)
>>>
>>> Cheers,
>>> Jean-Michel
>>>
>>> On Wed, Jul 27, 2011 at 09:16:27AM -0700, Matthew Mazloff wrote:
>>>> Hello,
>>>>
>>>> Shouldn't seaice_growth.F include the header file:
>>>>
>>>> #include "SEAICE_OPTIONS.h" ?
>>>>
>>>> Thanks
>>>> Matt
>>>>
>>>>
>>>> ps> This comes up because I am having issues of too much ice
>>>> accumulation in the Southern Ocean with the latest seaice package.
>>>> It may very well be due to forcing or ocean state, not a seaice
>>>> model problem.  When the thickness gets too extreme, however, the
>>>> LSR solver crashes.  So I can make a little progress diagnosing
>>>> this, I want to set
>>>> #define SEAICE_CAP_HEFF
>>>> and felt it should go in
>>>> SEAICE_OPTIONS.h
>>>> but realized that it cannot go there...thus the question
>>>>
>>>>
>>>>
>>>>
>>>>
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