[MITgcm-devel] free drift ice model

[Martin Losch]

Hi Matt, Patrick et al.

I am very confident about the C-grid dynamics in seaice. As D. says,  
we need to write it up! With the C-grid the ice-ocean drag works. You  
can even use different formulations, the "intuitive" one where ice  
assumed to float on top of water (with no draft), and the Hibler 
+Bryan87 formulation, which has other assumptions that may not be  
optimal, but both work, the former runs in Dimitris' high res cube.  
Correct my if I am wrong.
I am only using C-grid in my (coarse) runs (2deg "isotropic" grid).

M.
On 30 Nov 2006, at 00:59, Patrick Heimbach wrote:

>
> Hi there,
>
> just some small comments:
>
> On Nov 29, 2006, at 6:40 PM, Dimitris Menemenlis wrote:
>
>> Matt, I am going to guess that free drift is probably a good  
>> estimate for most
>> of Southern Ocean, except close to coastlines.  I don't know what  
>> your A and B
>> numbers should be, they would depend on drag coefficients, etc.   
>> Look for papers
>> by Miles McPhee on topic.  Although most of his work is for Arctic  
>> Ocean, I
>> think that his estimates over first year ice should be applicable  
>> for Southern
>> Ocean.
>
> Should maybe be a bit careful re. applicability of Arctic numbers
> for Antarctic sea-ice (latter seems more "loose", so more in free  
> drift).
> But maybe ok as first guess.
>
>>> I believe in the current model set up the wind stress acts on the  
>>> ocean as if
>>> the ice wasn't there.
>>
>> Not true anymore.  Martin's magic C-grid formulation makes ice- 
>> affected ocean stress possible.  We need to write it up.   
>> Apparently it's a big deal for sea-ice models.  Trying to iron out  
>> residual problems with growth, etc., first.
>
> Maybe again be careful in stating what works when.
> Matt probably still has B-grid code enabled for which
> his assumption is correct.
> But good to hear, the C-grid code has it.
> Might be worth switching then if it's "well" tested. Is it?
>
> BTW,
> I ran v3.iter0 with latest growth code.
> Seaice concentration misfits is reduced by 2/3, not bad.
> Still unclear re. fin.diff. sensitivities.
> Question is, which part of the code did it.
>
> -p.
>
>
>
>
>> Cheers, D.
>>
>> -- 
>> Dimitris Menemenlis <menemenlis at jpl.nasa.gov>
>> Jet Propulsion Lab, California Institute of Technology
>> MS 300-323, 4800 Oak Grove Dr, Pasadena CA 91109-8099
>> tel: 818-354-1656;  fax: 818-393-6720
>> _______________________________________________
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>> MITgcm-devel at mitgcm.org
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>
> Dr 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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