[MITgcm-support] seaice_salinity

Matthew Mazloff mmazloff at MIT.EDU
Tue Nov 11 22:49:42 EST 2008 

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


On Nov 11, 2008, at 7:37 PM, Dimitris Menemenlis wrote:

> 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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>>> 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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