[MITgcm-support] How to choose obc balance coefficients?

[Camille Mazoyer]

Dear all,

I have questions about the OBC balance term, and maybe somebody can 
answer me here. I have other questions, but I think I'm going to write 
other mails, to seperate questions.

I'm not sure about the balance coefficient I should use for my OBC: I 
have 2 OBC (south and West). Other boundaries are land. I'm working on a 
small scale area (200 Nx, 100 Ny, 75 Nz with a grid of 100m scale ). 
Could you correct me if I'm wrong, but what I understand about the 
balance coefficient is:

- the higher it is, the bigger is the correction

- so if I am confident about the South OBC values I give,  and not 
confident about the West values I give: I should give a small coeff like 
1 for south, and a bigger coeff like 2, 3, 4 or more (?) for west OBC.  
That means OBC South will be less changed than West OBC to ensure zero 
net transport. Usually, we give a small coeff for an OBC where we we 
know the values, and we want to set the values, and a big coeff for an 
OBC where we don't care if the flow is adjusted. Is that correct?

So if I'm not sure about one OBC more than the other,  I can have 
coeff=1 for both.

My last question: to sum up, how to choose coefficients?

Thanks a lot,

Camille

-- 
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Camille Mazoyer
Phd Student
Mediterranean Institute of Oceanography (MIO)
Institut de Mathématiques de Toulon (IMATH)
Université de TOULON
Bat X - CS 60584
83041 TOULON cedex 9
France
tel: +33.4.94.14.24.50
Email: mazoyer at univ-tln.fr
http://mio.pytheas.univ-amu.fr/
http://imath.fr/