[MITgcm-devel] selectP_inEOS_Zc

[Martin Losch]

Hi Jean-Michel,

I agree that it would be best to add the shelficeLoadAnomaly to phi0surf already in ini_psurf.F 
Would you like me to do that? It’s not going to change any verification results, because we don’t use any nonlinear pressure (selectP_inEOS_Zc) with the shelfice-tests (in isomip).

What I still do not understand: Why is the loadAnomaly in phi0Surf for selectP_inEOS_Zc=0 but not for selectP_inEOS_Zc=2?

Martin

> On 16. Jan 2018, at 03:25, Jean-Michel Campin <jmc at mit.edu> wrote:
> 
> 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
>>>> 
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