[MITgcm-devel] recently added SHELFICEMassStepping in pkg/shelfice

[Daniel Goldberg]

Hi J-M

Sorry for taking so long to respond. I think my fault, actually, that I did
not explain shelfIceMassDynTendency in SHELFICE.h. Also my hardcoded ice
density was a bit of a hack, as I acknowledged in the comment. Agreed that,
to be consistent with all else, the MassDynTendency should be in mass per
unit area rather than elevation units. Also fine with the _RS to _RL
conversion, of course.

pkg/streamice has its own ice density parameter. how extensively is
rhoShelfice used? Is it at all worth attempting to force consistency
between the packages (e.g. by using a single parameter in PARAMS.h)?

Thanks
Dan

On Fri, Jan 9, 2015 at 5:48 PM, Jean-Michel Campin <jmc at ocean.mit.edu>
wrote:

> Hi Dan and Martin,
>
> regarding the newly added option "SHELFICEMassStepping"
> and new S/R SHELFICE_STEP_ICEMASS:
>
> I realized that the units of forcing field array
>  "shelfIceMassDynTendency" are not documented (in SHELFICE.h, partly my
> fault),
> and would like to change it from a thickness tendency contribution
> to a mass tendency per unit area [kg/m^2/s], and taking
> this opportunity to remove the hard coded "910." number
> (which represents ice-shelf density, but is inconsitent with
> pkg/shelfice parameter "rhoShelfIce").
> Dan, are you OK with this modification ?
>
> An other minor thing: I am thinking of changing few field arrays
> in pkg/shelfice (including shelficeMass, which can now be stepped forward)
> from _RS to _RL ; this should have very little consequences since
> almost nobody uses RS=real*4. I think that by upgrading few arrays
> there from _RS to _RL I can get 1 cg2d matching digits (currently: zero
> digits)
> when I run testreport with -r4 option, see e.g.:
> http://mitgcm.org/testing/results/2015_01/tr_danton_20150103_2/summary.txt
>
> Cheers,
> Jean-Michel
>
>
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-- 

Daniel Goldberg, PhD
Lecturer in Glaciology
School of Geosciences, University of Edinburgh
Geography Building, Drummond Street, Edinburgh EH8 9XP


em: D <dgoldber at mit.edu>an.Goldberg at ed.ac.uk
web: http://ocean.mit.edu/~dgoldberg
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