[MITgcm-support] doubt regarding OBCs

[Himansu Pradhan]

Yes Sir

your explanation makes complete sense (as seen from my output for different
experiments. )

thanks a lot.

On Sun, Jul 22, 2012 at 10:00 PM, Nicolas Grisouard
<grisouard at cims.nyu.edu>wrote:

>
> Hi,
>
> (1) The default behavior for the boundaries is periodic. If you set
> useOBCS as false, then what you get on one side is the extension of what
> happens on the opposite side.
>
> (2) Now if you just set useOBCS as true without specifying anything (like
> orlanski), then the default value prescribed at the "open" boundaries is
> zero for all perturbation variables, and the reference profiles for the
> stratification agents. The obcs package does not choose values for you,
> unless you ask for a semi-automatic package, like orlanski, to be activated.
>
> Does that make sense with what you see?
>
> Cheers,
> Nicolas.
>
> On Jul 22, 2012, at 1:07 AM, Himansu Pradhan <oceancalling at gmail.com>
> wrote:
>
> > Hi MITgcm users,
> >
> > i have a doubt regarding Open Boundary Conditions.
> > I have 3 experiments configured as :
> > In
> > expA
> >
> > data.pkg
> > useOBCS = .FALSE.
> >
> > here i get values at boundary.
> >
> > expB
> >
> > data.pkg
> > useOBCS = .TRUE.
> >
> > data.obcs
> > # Open-boundaries
> > &OBCS_PARM01
> > OBCSfixTopo=.FALSE.,
> > OB_Jnorth=190*-1,
> > OB_Jsouth=190*1,
> > OB_Ieast=170*-1,
> > OB_Iwest=170*1,
> >
> > useOrlanskiN/S/E/W=.FALSE.,
> >
> > here i get "ZERO" values at boundary.
> >
> > expC
> > data.pkg
> > useOBCS = .TRUE.
> >
> > data.obcs
> > # Open-boundaries
> > &OBCS_PARM01
> > OBCSfixTopo=.FALSE.,
> > OB_Jnorth=190*-1,
> > OB_Jsouth=190*1,
> > OB_Ieast=170*-1,
> > OB_Iwest=170*1,
> >
> > useOrlanskiN/S/E/W=.TRUE.,
> >
> > here at the boundary, values are according to orlanski boundary
> conditions. this is OK.
> >
> > My query is (1), in expA, what is happening at the boundary ? where do i
> get those values / what values are they ?????
> >
> > (2) In expB , pls explain me what is happening here...................
> >
> > thanking all in advance,
> >
> > himansu
> > _______________________________________________
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> > MITgcm-support at mitgcm.org
> > http://mitgcm.org/mailman/listinfo/mitgcm-support
>
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