[MITgcm-devel] [MITgcm-cvs] MITgcm/pkg/seaice CVS Commit

[Gael Forget]

Hi Martin,

> what a job you have done!
Thanks. It was a good fight.

> Of course now I don't recognize anything in seaice_growth.F, but I will learn.
My intention was to make this routine an easy read. We will see..

> Quick comments before I do so:
> 
> Obviously I could not convince you that the "vintage bug" really isn't one. How can you convince me? I guess we should ask Jinlun how to do it right. And then equivalent part for snow is treated differently ...
It is very well possible that I did not get it right. But the more I circled around it, the more it felt 
like a bug -- very much like the one you fixed in v1.34 of growth.F (Nov 2006) in fact. Maybe I just did not get 
the hsnow/heff treatment difference that you are referring to, and we will need a fix. I reported the questionable 
operation as a comment in seaice_growth.F  v1.89. Let's come back to this question in a few days, if that is ok with you.

> The part about "truncating" AREA is the simple "ridging scheme" of this model. Currently I do not see this happening in the part of the code that is used with SEAICE_GROWTH_LEGACY undefined. Instead somewhere in the beginning of the routine AREA is reset to AREAmax. I think that this should really happen at the end, because we must not leave seaice_growth with an AREA>1, does not make sense.
See lines 874-875 that apply to both the 'legacy' and 'evolution' branches.

> Also areaMax should be used in both parts of the code (and should become a runtime parameter).
This is what I have in mind, but I decided it was better to wait. There are several 
other things that would be worth changing in SEAICE.h and seaice_readparms.F,
but I preferred to keep my modifications all enclosed in seaice_growth.F to this point.

> I am curious to find out what you will do next. In the meantime I have not yet gotten around to finishing the verification experiment that we want to use for checking the budgets ... But I'll get there.
Excellent. I am counting on you for this part. I tried to, a priori, get you as close as 
possible to balanced  budgets. Especially in the 'evolution' branch. But I am sure I 
missed a thing or two. I am looking forward to hearing from you in this regard.
Wouldn't the so-called 'vintage bug' break heat conservation by the way?

Cheers,
Gael


> 
> Martin
> 
> On Oct 15, 2010, at 9:10 PM, Gael Forget wrote:
> 
>> Update of /u/gcmpack/MITgcm/pkg/seaice
>> In directory faulks.csail.mit.edu:/u/u2/gforget/MITgcm/pkg/seaice
>> 
>> Modified Files:
>> 	seaice_growth.F 
>> Log Message:
>> 
>> 
>> Merging seaice_growth codes -- part 3 -- the merging, at last.
>> 
>> This check-in completes the overall 10/2010 revision and merging process, by
>> 
>> - adding a header that explains unit/sign/naming conventions.
>> - introducing areaMax parameter that is, for now, hardcoded to 1.
>> - re-including the 'vintage bug' as a comment -- in case I got it wrong.
>> - bracketing 'IF (useRelativeWind)' with '#ifdef ALLOW_ATM_WIND'  
>> consistent with what pkg/exf does.
>> - merging the '_if.F' features that differ from what is in legacy code:
>> - option to actually grow ice over open water, which legacy code 
>>   only virtually takes into account in the area tendency (I think).
>> - let melting by ocean reduce area (as melting by atm alone does in legacy).
>> - different criteria for rain->snow (incl. as comments).
>> 
>> The added features are bracketed out of legacy code, so this 
>> revision did not affect forward results. A couple cosmetic modifications
>> changed adjoint results by only three digits. I will only update those.
>> 
>> 
>> 
>> 
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> 
> Martin Losch
> Martin.Losch at awi.de
> 
> 
> 
> 
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