[MITgcm-support] OBCS sponge and prescribe code checked in

[Patrick Heimbach]

Hi Martin, Uli, and others,

I've just checked in code in pkg/obcs/ that
* ALLOW_OBCS_PRESCRIBE allows prescibing time-dependent obcs values,
* ALLOW_OBCS_SPONGE sponge layers
* ALLOW_OBCS_BALANCE rudimentary balancing of normal barotropic flow

tag is checkpoint55a_post

The stuff I checked in at least doesn't break 
the existing verif.'s that use obcs ;o)
The code has been / is used in a few open boundary setups,
it compiles ok, but no guarantee that the merging may have
broken some of the new stuff. 
Any feedback on bugs, improvements etc are welcome.

One feature/caveat is that the time-dependent prescibe 
runs in conjunction with exf, cal., i.e.
S/R OBCS_CALC calls S/R EXF_GETOBCS
If someone wants to volunteer to call 
external_fields_load alternatively, please.

The files read are 
xz files (northern, southern boundary)
yz files (eastern, western boundary)

I've put a few "template" CPP options and runtime parameter files under
http://mitgcm.org/cgi-bin/viewcvs.cgi/MITgcm_contrib/heimbach/obcs_prescribe/

A verif. experiment will hopefully come soon.

-Patrick



Quoting Patrick Heimbach <heimbach at MIT.EDU>:

> 
> Hi Martin,
> 
> there is code for sponge layers and code for reading
> 2D (xz, yz) boundart slices (was part of ECCO).
> I wanted to merge it with the main code last week,
> but didn't have time since I also had to catch up
> with the adjoint (-> c55).
> Will try it in the first half of this week
> (remind me ;o).
> 
> -Patrick
> 
> Quoting Martin Losch <mlosch at awi-bremerhaven.de>:
> 
> > Hi,
> > now the obcs-package has got me. In the global_ocean.90x40x15 
> > experiment, I would like to introduce open boundaries in the south 
> > and/or north to emulate polar regions. Now the simplest and dirtiest 
> > way to do it would be through restoring in external_forcing. But I want 
> > to do it the hard and clean way and use the obcs package (o: A few 
> > questions arise:
> > 1) as a general rule/how-to I start by modifying obcs_calc, so that 
> > after calling obcs_calc, the boundary values at time myTime+deltaT are 
> > known. Why myTime+deltaT, why not the current time=myTime?
> > 2) ALLOW_OBCS_SPONGE: Is there code for sponge layers, or am I 
> > completely responsible for it myself (subroutine obcs_sponge_u/v/t/s)? 
> > As far as I know, a sponge layer is not much more than a restoring 
> > zone, correct? If I use a sponge layer (#define ALLOW_OBCS_SPONGE), 
> > will I still have an open boundary? Or in other words: just having 
> > restoring in external_forcing.F is not the same as ALLOW_OBCS_SPONGE 
> > and do the restoring somewhere in obcs_sponge_u/v/t/s, etc? It seems 
> > so.
> > 3) not quite OBCS, but related. I want to read my open boundary values 
> > from a file (in calc_obcs), so I have to create code for that, fair 
> > enough; but because I only want to read one xz-slice, for example, 
> > (there is even an MDSIOREADFIELDXZ, impressive), I have a problem with 
> > exchanging the xz-slice, or did I just not find the excange_xz_r? file? 
> > Does anyone have experience with this?
> > 
> > Martin
> > 
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://dev.mitgcm.org/mailman/listinfo/mitgcm-support
> > 
> 
> 
> --------------------------------------------------------
> Patrick Heimbach   Massachusetts Institute of Technology
> FON: +1/617/253-5259                  EAPS, Room 54-1518
> FAX: +1/617/253-4464             77 Massachusetts Avenue
> mailto:heimbach at mit.edu               Cambridge MA 02139
> http://www.mit.edu/~heimbach/                        USA
> 
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
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> 


--------------------------------------------------------
Patrick Heimbach   Massachusetts Institute of Technology
FON: +1/617/253-5259                  EAPS, Room 54-1518
FAX: +1/617/253-4464             77 Massachusetts Avenue
mailto:heimbach at mit.edu               Cambridge MA 02139
http://www.mit.edu/~heimbach/                        USA