[MITgcm-support] documentation about OBC Orlanski and Balance Flow

[Martin Losch]

Hi Camille,

I think the balance-flow option is properly described in the docs. It’s just a correction after the conditions have been computed.
The Stevens BC are now available for all boundaries (although I have to admit, that I used and tested the E-W boundaries the most)
You can also mix the BCs, ie. have Stevens for one boundary and Orlanski for another, and neither for a third boundary.

For details of the Orlanski BCs you’ll probably have to read the code (and refer to textbooks), I am afraid.

Martin

> On 01 Feb 2016, at 16:22, Camille Mazoyer <mazoyer at univ-tln.fr> wrote:
> 
> Hi,
> Thank you for your reply Matthew and Martin. I already read the doc http://mitgcm.org/public/r2_manual/latest/online_documents/node236.html, but I didn't try the examples. I will run these examples very soon. I already did google "mitgcm + OBC", and as you said, and I found a lot of discussion, but I didn't see yet an explanation of OBC_balance or how Orlanski  method is implemented. But, I will search again if some discussions can help me.
> The Stevens BCs  are currently only implemented for eastern and western boundaries no? So if I have 3 boundaries (Eastern, Wester, South), I can't use it no? Or can I mixed Orlanski for South boudary and Stevens for Eastern and Western?
> 
> Thank you,
> Camille
> 
> 
> Le 29/01/2016 09:31, Martin Losch a écrit :
>> Hi Camille,
>> 
>> there is some documentation about the obcs package here: <http://mitgcm.org/public/r2_manual/latest/online_documents/node236.html>
>> There is very little about the Orlanski option but at least it points you to some examples (the verification experiments that Matt mentioned).
>> 
>> I often use the Stevens BCs, which are some kind of mixture of prescribe values and a radiation condition. For purely radiative BCs, the Orlanski option is probably the best.
>> 
>> Martin
>> 
>>> On 28 Jan 2016, at 16:52, Camille Mazoyer <mazoyer at univ-tln.fr> wrote:
>>> 
>>> Dear all,
>>> I just start using MITgcm as I will use it during my thesis for creating a configuration on the rade de Toulon, France.
>>> Currently, I'm trying to understand how open boundary conditions work, with these two steps:
>>> - orlanski scheme wich seems to be a predictor step, if I understand well, where we use the pression of the previous step. We calculate velocities, temperature and salinity we will have to correct during the next step
>>> - use of balance flow wich seems to be a corrector step of these variables (Is this right?)
>>> I only find a few explanations in the doc (mainly explaining the CPP Key). I also have read the paper of Orlanski, 1976.
>>> Would you have more documentations / publications about the method used in the MITgcm (orlanski and balance flow)? (about the numerical part, or the method, ...)
>>> 
>>> Thank you very much for your help,
>>> Camille Mazoyer
>>> 
>>> -------------------------------
>>> 
>>> Camille Mazoyer
>>> Phd Student
>>> Mediterranean Institute of Oceanography (MIO)
>>> Université de TOULON
>>> Bat X - CS 60584
>>> 83041 TOULON cedex 9
>>> France
>>> http://mio.pytheas.univ-amu.fr/
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>> 
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> -- 
> ------------------------------------------
> Camille Mazoyer
> Phd Student
> Mediterranean Institute of Oceanography (MIO)
> Université de TOULON
> Bat X - CS 60584
> 83041 TOULON cedex 9
> France
> http://mio.pytheas.univ-amu.fr/
> 
> 
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