[MITgcm-support] Open Boundary Conditions in MITgcm

[Klymak Jody]

Hi Serge,

I use the Orlanski condition, but it really doesn't work except for trivial waves.  So what I really do is make the boundaries far from my domain of interest and then use the obcs_sponge to drive the boundaries how I want.  I usually just do U or V and drive T (and S if I ever used S) to the reference value.  Somewhat annoyingly I set the boundary velocities in the Orlanski code.

I keep thinking that it would be worthwhile for someone with coding chops to add to obcs package the option to specify lateral boundary conditions, perhaps even reading them from a file.  I'd be interested to hear how other people do it.  

Cheers,   Jody




On 2011-02-23, at 11:31 PM, Martin Losch wrote:

> Serge,
> 
> you might have noticed that the documentation of the obcs-pkg is incomplete:
> <http://mitgcm.org/public/r2_manual/latest/online_documents/node236.html>
> but can find all the information about the OB_Ieast etc. indices and other run-time parameters. For more you'll have to consult the code in pkg/obcs and the corresponding experiments in verification I am afraid.
> 
> There is a orlanski-radiation conditions. To turn it on you need to re-compile with 
> #define ALLOW_ORLANSKI
> in OBCS_OPTIONS.h and useOrlanskiNorth/South/East/West=.true. for the boundary of intererst. There are some experiments that use this option (e.g. tutorial_plume_on_slope, dome). If you are not happy with that, you'll need to implement something on your own.
> 
> I hope this helps,
> Martin
> 
> On Feb 20, 2011, at 5:12 PM, fancer fancer wrote:
> 
>> Hello, MIT gcm support.
>> I am novic at modeling with MIT gcm, thus I have several questions about this model and about obcs package, especially.
>> 	• My first application describe itnternal waves propagation, generated by temperature and salinity stratification, in 2D area. This is the trivial task, because MIT gcm has internal waves verification example. It is necessary, what waves go through boundaries, but not reflect of that boundaries. How made it with obcs package or with other way? I made many experiments, but whitout positive results.
>> 	• Is there more detailed information about open boundies setting in MIT gcm, it is desirable with picture, where OB_Ieast, OB_Iwest, OB_Jsouth, OB_Jnorth represented in a modeling area?
>> In advance, thanks for help.
>> Yours sincerely, Serge Semin.
>> P.S, Sorry for my emglish, I'm still learning.
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> 
> 
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