[MITgcm-support] seaice_salinity

[Matthew Mazloff]

Hi Michael,

Actually I wasn't concerned with the SEAICE_strength as I thought  
most SO ice is new ice and sloshy.  Sloshy ice should be weak so I  
was ok with low strenght.  But sloshy ice is rough and has high  
drag....or so I thought.  I really don't know much about all this sea- 
ice stuff.

My biggest concern is how unstable the seaice model is!  Do you know  
any tricks?  Perhaps turning down max vel. or shortening the time step?

-Matt


On Nov 18, 2008, at 9:12 AM, Michael Schodlok wrote:

> Matt,
> The values for SEAICE_WaterDrag and SEAICE_Drag seem to be ok,
> at least those are similar to what we use in ECCO2. However,  
> SEAICE_strength
> seems to be a bit low. The optimized ECCO2 value is around 13000. I  
> guess
> that's what you're concerned with, not the value of SEAICE_drag,  
> right?
> cheers
> Michael
>
>
>> Hello,
>>
>> OK, so I was only able to make the seaice dynamics stable by turning
>> down the drags ( I was able to run with SEAICE_WaterDrag = 5 and
>> SEAICE_drag = 0.001) and turning down the SEAICE_strength (to a value
>> of 5e-3) and turning down the lsr error to 1e-5.
>>
>> I am concerned because a very small SEAICE_drag is likely unrealistic
>> for the SO's largely rough first year ice, and (perhaps more
>> importantly) because if the winds increase during optimization it may
>> drive the model back unstable.
>>
>> I am also disappointed in that running with seaice diagnostics on and
>> LSR_error = 1e-5 has about doubled the runtime...making using seaice
>> dynamics not very practical.
>>
>> So any advice...options.  Would coding a simple free drift model be
>> more stable (and perhaps somewhat realistic).  Any ideas?
>>
>> Thanks a lot,
>> Matt
>>
>>
>>
>>
>> On Nov 11, 2008, at 8:13 PM, Dimitris Menemenlis wrote:
>>
>>
>>> The CS510 solution also has some very saline water in narrow fjords
>>> around Antarctica.  I think what might be happening is that ice is
>>> acting as a salinity pump, taking freshwater out of the fjord, when
>>> ice dynamics are turned on, but there is no mechanism for flushing
>>> the salty water out in the model ocean.  Let me know what you
>>> find.  D.
>>>
>>> On Nov 11, 2008, at 7:49 PM, Matthew Mazloff wrote:
>>>
>>>
>>>> Hi Dimitris,
>>>>
>>>> The extremes are happening over narrow fjords.  But with seaice
>>>> dynamics off they dont occur.  The coldest it gets is -3.14.
>>>>
>>>> And yes, I have  SEAICE_gamma_t     = 259200.
>>>>
>>>> Thanks for the help,
>>>> -Matt
>>>>
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>>
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>
>
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>
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>
> Michael Schodlok <schodlok at jpl.nasa.gov>
> Jet Propulsion Lab/
> California Institute of Technology
> MS 300-323
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