[MITgcm-support] seaice_salinity

Tue Nov 11 22:37:22 EST 2008

Matt, are you using SEAICE_gamma_t ?  This would allow surface  
temperature to go below freezing point, on purpose, both because it is  
more physically realistic and also more stable for adjoint, but  
dynstat_theta_min = -5.8 is too much.  Could it be that you are  
interpolating some land-surface air temperature over an ocean grid  
point?  Is this extreme happening in a narrow fjord?  D.

On Nov 11, 2008, at 8:51 PM, Matthew Mazloff wrote:

> 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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>>>>>>
>>>>>> ---
>>>>>> 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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>>>> ---
>>>> 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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>> ---
>> 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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