[MITgcm-devel] selectP_inEOS_Zc

[Jean-Michel Campin]

Hi Martin,

It seems that you found the problem with S/R INI_PRESSURE & selectP_inEOS_Zc=2,
and I have the impression that this problem was there very early on (when 
pkg/shelfice was added); I thought about this (e.g. in this commit message:
 http://mailman.mitgcm.org/pipermail/mitgcm-cvs/2013-April/027805.html )
but never fixed it.

I don't think it would be nice to add a call to shelfice_forcing_surf in the
initialisation part, but may be we could just copy the relevant part, lines 124-131
of shelfice_forcing_surf.F at the bottom of ini_psurf.F (with proper #ifdef and
IF ( useShelfIce ) THEN ...), which is called just before INI_PRESSURE ?
Since there is already some pkg/cd_code pieces in ini_psurf.F, would not be
too bad to have also few pkg/shelfice bits there.

Cheers,
Jean-Michel

On Fri, Jan 12, 2018 at 12:27:04PM +0100, Martin Losch wrote:
> Hi Jean-Michel,
> 
> I still don???t quite understand why phiHyd.00000000.t001.nc are different for different selectP_inEOS_Zc, but I think it has to do with ini_pressure.F where totPhiHyd=0 initially and phi0surf does not yet contain the contribution from SHELFICEloadAnomaly. This contribution is only added in shelfice_forcing_surf, which is called from external_forcing_surf after the initialisation (not why this contribution is actually there, when selectP_inEOS_Zc=0) . Anyway, when I include a call shelfice_forcing_surf at the beginning of ini_pressure, I get the appropriate value of totPhiHyd in the ice shelf (and not zero) already in ini_pressure (which is probably necessary to compute the correct pressure). 
> 
> I now think, that the different totPhiHyd???s in phiHyd.*.nc are not very relevant to the balance problem, because the diagnostics PHIHYD (which are filled in dynamics where the gradients of phi0surf matter) are actually independent of selectP_inEOS_Zc.
> 
> The balancing problem remains to be solved. It has very likely to do with the vertical integration of phiHyd in the code and in the ???gendata??? script.
> 
> Martin
> 
> > On 11. Jan 2018, at 19:42, Jean-Michel Campin <jmc at mit.edu> wrote:
> > 
> > Hi Martin,
> > 
> > I will take a look at this soon, and will let you know.
> > 
> > Cheers,
> > Jean-Michel
> > 
> > On Thu, Jan 11, 2018 at 05:20:34PM +0100, Martin Losch wrote:
> >> Hi Jean-Michel,
> >> 
> >> Dustin and I are trying to debug his configuration with the shelfice package. We are struggling to make the initial conditions ???balance??? (i.e. not have large initial adjustments). 
> >> I can do it for eosType=???JMD95z???, but not for JMD95p and MDJWF. The latter two use selectP_inEOS_Zc = 2 and the former uses 0 (very simple pressure = g*rho*zc)
> >> When I look at the results of phiHyd (i.e. totPhiHyd as stored in phiHyd.*.nc), then I see that for selectP_inEOS_Zc = 2, phiHyd = 0 within the ice shelf, but for selectP_inEOS_Zc = 0 is corresponds to the value that is prescribed in SHELFICEloadAnomalyFile. I am afraid, that as a consequence, the phiHyd at the bottom of the ice shelf is not correct for selectP_inEOS_Zc = 2 (at least it looks like that in timestep 0: there???s a lateral gradient that I want to avoid with prescribing SHELFICEloadAnomaly).
> >> 
> >> Can you remember, why there is this different behavior for the different selectP_inEOS_Zc?
> >> I would expect the totPhiHyd to have the contribution of SHELFICEloadAnomalyFile (in the end it???s added as phi0surf in diags_phiHyd) in all cases.
> >> 
> >> Martin
> >> 
> >> _______________________________________________
> >> MITgcm-devel mailing list
> >> MITgcm-devel at mitgcm.org
> >> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-devel
> > _______________________________________________
> > MITgcm-devel mailing list
> > MITgcm-devel at mitgcm.org
> > http://mailman.mitgcm.org/mailman/listinfo/mitgcm-devel
> 
> _______________________________________________
> MITgcm-devel mailing list
> MITgcm-devel at mitgcm.org
> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-devel