[MITgcm-support] changes related to pkg/shelfice (Jean-Michel Campin)

[Madeline Miller]

Hi Jean-Michel and Martin,

Can you clarify what the other parts of the partial cell are filled with
(air or ice)? Is this to account for the ice shelf losing contact with the
water or to allow the ice shelf to have higher resolution bumps?

Madeline


> Today's Topics:
>
>   1. changes related to pkg/shelfice (Jean-Michel Campin)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 26 Apr 2012 12:05:21 -0400
> From: Jean-Michel Campin <jmc at ocean.mit.edu>
> To: mitgcm-support at mitgcm.org
> Subject: [MITgcm-support] changes related to pkg/shelfice
> Message-ID: <20120426160521.GA29910 at ocean.mit.edu>
> Content-Type: text/plain; charset=us-ascii
>
> Hi pkg/shelfice users,
>
> The hydrostatic pressure calculation under ice-shelf has been changed today
> ( model/src/set_parms.F, cvs version 1.14 :
> > account for partial cells in surface level below ice-shelf for
> hydrostatic
> > pressure calculation (set uniformFreeSurfLev to F if using shelfice pkg)
> )
> in order to account for partial-cell in the surface-level in contact
> with the ice-shelf (just below the ice-shelf).
>
> pkg/shelfice allows to have partially filled grid-cell (a sea-water
> fraction
> given by hFacC below an ice fraction (dry) above) below ice-shelf.
> In the previous and original version, the hydrostatic pressure was
> calculated
> assuming a 100% sea-water fraction in the surface grid cell below
> ice-shelf.
> This is no longer the case and the partial-cell fraction is now taken
> into account. This is more consistent with the remaining part of the model
> which knows about partial cell filling.
>
> Making the transition to the new version:
> You might need to update the input file SHELFICEloadAnomalyFile
> (specified in data.shelfice) if the previous loading anomaly file was
> accounting for only fully ice (dry) grid-cell, consistent with the
> original pressure calculation.
> See changes in MITgcm/verification/isomip/input/gendata.m, cvs version 1.2.
> Note that the changes do not affect the way partial-cell are defined,
> so that restarting with the new version but from a pickup file that was
> produced with the original version should not be a problem.
>
> If for some reasons, after updating your code, you want to revert back
> to the original version (to reproduce the old results), you will need
> to edit the file "model/src/set_parms.F":
>  66       uniformFreeSurfLev = usingZCoords
>  67 C- Note: comment line below to revert to full-cell hydrostatic-pressure
>  68 C        calculation in surface grid-cell below ice-shelf
>  69       uniformFreeSurfLev = usingZCoords .AND. .NOT.useShelfIce
>  70       IF ( selectNHfreeSurf.NE.0 .AND.
> and comment out the line 69:
>  69 c     uniformFreeSurfLev = usingZCoords .AND. .NOT.useShelfIce
>
> And if you have questions, you can contact the support list.
>
> Thanks,
> Jean-Michel
>
>
>
>
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