[MITgcm-support] Ricr and MLDs

[Baylor Fox-Kemper]

Hi David,
   Do you get exact agreement (i.e., bitwise), or just approximate  
agreement?  It looks to me like that is the right place to change  
Ricr, but maybe you haven't reduced it enough to see a noticeable  
effect in MLD...  Or, perhaps reducing Ricr was a bad idea (it was  
mine, so I can tell you not to trust the source too much...).
   Cheers,
    -Baylor


On Jul 31, 2006, at 12:42 PM, David Ullman wrote:

> Hello all,
> I'm working with Galen McKinley and Stephanie Dutkiewicz to fine  
> tune our 0.5X0.5 North Atlantic setup.  Initially we were getting  
> mixed-layer depths that were too deep in comparison to the WOA01  
> data.  It was suggested that we reduce our Richardson number cutoff  
> (Ricr) in the KPP scheme to shallow the MLDs.
>
> From the MITgcm website and my own searches through the code, it  
> seem as though the only place to make this change is under the  
> kpp_readparms.F script.  I reduced the Ricr to .27 and .24 (by  
> altering the file under my /na_test/code folder so as not to change  
> the original code), recompiling after each reduction to get two  
> executables with reduced Ricr.
>
> I then used a pickup file from a 66-year spin-up that used the  
> original Ricr of .30.  I ran the new Ricr runs for 5 years each  
> from this pickup.  At the end of these runs, I compared the MLDs.   
> I found that there was no difference in MLDs between Ricr=.3, .27,  
> or .24.  This seems a bit strange.
>
> Am I missing something in my setup?  Is there perhaps some other  
> place in the code where I should adjust the Ricr?
>
> Thanks for your help,
>
> David Ullman
>
> Graduate Student
> Atmospheric and Oceanic Sciences
> University of Wisconsin Madison
> ullman at wisc.edu
>
>
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