[MITgcm-devel] selectP_inEOS_Zc

[Martin Losch]

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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