[MITgcm-support] eta at OBCS

[Van Thinh Nguyen]

Hi Stefano,

Could you please tell me where the offline "Vbaro=c*eta/H" located? I 
also try to impose eta on OBs, too? I looked around in all exf_* and obcs* 
but I couldn't find this.

thanks a lot!

Van Thinh
-----------------

On Wed, 19 Oct 2005, Stefano Querin wrote:

> Hi Ming,
> just some hints (I'm a bit busy in these days, sorry...).
> There are many mails about eta and OBCs: try to find them on the mitgcm 
> website, you will find lots of informations.
> Anyway, if you need to impose eta on the OB (i.e. external tidal forcing...), 
> I suggest you to convert the sea surface elevation (eta) into barotropic 
> velocity (Vbaro) "offline":
>
> Vbaro=c*eta/H
>
> c=(gH)**1/2
>
> g: gravity acc.;
> H: water column heigth;
> c: celerity of small (compared to the water column heigth: eta<<H) amplitude 
> perturbations.
>
> It is also possible to impose u, v, w, T, S and eta as well: you have to 
> customize some routines (I modified obcs_prescribe_read.F , exf_set_obcs.F , 
> obcs_readparms.F , OBCS.h , OBCS_OPTIONS.h  in such a way to be able to read 
> OBeta values from files). Remember to set  #define NONLIN_FRSURF in 
> CPP_OPTIONS.h and nonLinFreeSurf~=0 in data (if I remeber correctly...): in 
> this case you must run only in hydrostatic mode.
>
> If you need a radiation condition on the OB: Orlanski OBC does not control 
> the inflow/outflow in the domain so you could obtain a very anomalous 
> increase/decrease in the sea surface level (for example, try to run the plume 
> on slope verification experiment for a longer period)!
>
> If there is something wrong, please someone correct me!
> Good luck!
>
> Stefano
>
>
> ----- Original Message ----- From: "Ming Guo" <gming at karluk.physics.mun.ca>
> To: <mitgcm-support at mitgcm.org>
> Sent: Wednesday, October 19, 2005 4:09 PM
> Subject: Re: [MITgcm-support] eta at OBCS
>
>
>> Is obcs_apply_eta.f the file should be included?
>> But I am not sure how to do it.
>> 
>> 
>> On Wed, 19 Oct 2005, Ming Guo wrote:
>> 
>>> Hi,
>>> anyone can give me some hints or examples of dealing with eta on open 
>>> boundary?
>>> 
>>> It seems that obcs only calculates u,v,w,s and t.
>>> 
>>> thanks,
>>> 
>>> Ming
>>> 
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>> 
>> _______________________________________________
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>
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