[MITgcm-support] seaice_salinity

[Matthew Mazloff]

Hello,

Continuing this thread.

With sea-ice dynamics off my model is stable.
With sea-ice dynamics on the model blows up.   It doesn't seem that  
ice is piling up or moving to fast (its speed actually maxes out  
immediately).  What is happening is the ice is getting very salty and  
SST is getting very cold.  Then I am assuming a massive convective  
event causes the model to blow up.
I do not understand why its letting
  dynstat_theta_min            =  -5.8076145068724E+00
as I have not defined SEAICE_VARIABLE_FREEZING_POINT
That is kind of odd to me...shouldn't more ice just form?

Any advice?

-Matt






On Nov 1, 2008, at 4:33 PM, Patrick Heimbach wrote:

>
> On Nov 1, 2008, at 7:13 PM, Matthew Mazloff wrote:
>
>> Hi Patrick,
>>
>> Yes you have it correct.  The MITgcm_contrib/high_res_cube/ 
>> cs510_adjoint/ settings work fine without dynamics, and model  
>> blows up when I turn on dynamics.
>>
>> So I can turn on ATMOSPHERIC_LOADING (any preference on what  
>> header file it goes in, and is there a runtime flag I need to turn  
>> on too) and try without adjustments.  Any other advice?  Are there  
>> parameters I can play with to stabilize the solution?
>
> Should go into CPP_OPTIONS.h
> (but it is already there if you're using the one from high_res_cube/ 
> cs510_adjoint/ ).
>
> You could try increase solver accuracy initially
> to make sure you have converged solution:
> LSR_ERROR          = 1.e-8,
>
> Other parameters to play with re. dynamics are
> SEAICE_strength
> SEAICE_waterDrag
> SEAICE_drag
>
> but not sure, what stabiling values ought to be.
>
> I would really try a pure NCEP run first, and with high solver  
> accuracy.
>
> -p.
>
>
>
>> And by the way, the blow up is gradual, the model runs for about  
>> 15 days before crashing....I'll look more into where the  
>> instability is occurring
>>
>> -Matt
>>
>>
>>
>> On Nov 1, 2008, at 3:47 PM, Patrick Heimbach wrote:
>>
>>> If easy, can you re-try with un-adjusted atmos. state?
>>> THere's a possibility that the adjusted fields you have
>>> reflect some compensation for lack of seaiceDynamics in prior runs.
>>>
>>> Another thing is use of ATMOSPHERIC_LOADING
>>> to include sea ice loading on the surface.
>>> But if I understand you correctly the
>>> MITgcm_contrib/high_res_cube/cs510_adjoint/
>>> settings work fine without dynamics, and model only blows with  
>>> dynamics(?)
>>>
>>> -p.
>>>
>>>
>>>
>>> On Nov 1, 2008, at 6:34 PM, Matthew Mazloff wrote:
>>>
>>>> Hi Patrick,
>>>>
>>>> I am using the adjusted atmos. state and the same  
>>>> SEAICE_OPTIONS.h and data.seaice as in the cube sphere adjoint.
>>>> http://mitgcm.org/cgi-bin/viewcvs.cgi/MITgcm_contrib/ 
>>>> high_res_cube/cs510_adjoint/
>>>>
>>>> -matt
>>>>
>>>>
>>>>
>>>> On Nov 1, 2008, at 2:52 PM, Patrick Heimbach wrote:
>>>>
>>>>>
>>>>> Matt,
>>>>> is this using adjusted atmos. state, or pure NCEP forcings?
>>>>> Also, are you using B-grid or C-grid,
>>>>> and which of the two solvers, LSR or EVP?
>>>>> -p.
>>>>>
>>>>> On Nov 1, 2008, at 4:07 PM, Matthew Mazloff wrote:
>>>>>
>>>>>> sorry, it wasn't the seaice_salinity....i had seaice dynamics  
>>>>>> on...meant to turn them off at runtime.
>>>>>>
>>>>>> So, new question:  using seaice dynamics makes my model blow  
>>>>>> up.  Any advice on how to increase stability when using seaice  
>>>>>> dynamics?
>>>>>>
>>>>>> -matt
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Oct 31, 2008, at 12:56 PM, Matthew Mazloff wrote:
>>>>>>
>>>>>>> Hello,
>>>>>>>
>>>>>>> My model crashes when I  #define SEAICE_SALINITY
>>>>>>>
>>>>>>> I just turned it on to keep up with ECCO2...but is this a  
>>>>>>> flag that is even worth using.  And if so, does anyone have  
>>>>>>> any advice (besides to turn it back off)?
>>>>>>>
>>>>>>> Thanks
>>>>>>> Matt
>>>>>>>
>>>>>>> ps> and could someone also let me know an expected value of  
>>>>>>> seaice_hsalt_max so I know if I have initialized it properly
>>>>>>>
>>>>>>> _______________________________________________
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>>>>>>
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>>>>>
>>>>> ---
>>>>> Patrick Heimbach | heimbach at mit.edu | http://www.mit.edu/~heimbach
>>>>> MIT | EAPS 54-1518 | 77 Massachusetts Ave | Cambridge MA 02139 USA
>>>>> FON +1-617-253-5259 | FAX +1-617-253-4464 | SKYPE patrick.heimbach
>>>>>
>>>>>
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>>>>
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>>> ---
>>> Patrick Heimbach | heimbach at mit.edu | http://www.mit.edu/~heimbach
>>> MIT | EAPS 54-1518 | 77 Massachusetts Ave | Cambridge MA 02139 USA
>>> FON +1-617-253-5259 | FAX +1-617-253-4464 | SKYPE patrick.heimbach
>>>
>>>
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>>
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>
> ---
> Patrick Heimbach | heimbach at mit.edu | http://www.mit.edu/~heimbach
> MIT | EAPS 54-1518 | 77 Massachusetts Ave | Cambridge MA 02139 USA
> FON +1-617-253-5259 | FAX +1-617-253-4464 | SKYPE patrick.heimbach
>
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