[MITgcm-support] Calculating sea ice export

[Martin Losch]

Hi Maddie,

you may want to use the diagnostics “ADVyHEFF” and “ADVySNOW”, which will give you the advective flux of snow and ice “volume” (i.e. per grid cell area) as the model computes it for advecting HEFF and HSNOW. To get mass, multiplying with the constant densities rhoIce and rhoSnow is necessary. 
If you use sIceLoad*SIvice, you’ll have to interpolate sIceLoad to v-points (or SIvice to C-points), which will introduce small differences to the advective fluxes above.

Martin

> On 12. Aug 2024, at 19:38, Madison Shankle <mgs23 at st-andrews.ac.uk> wrote:
> 
> Hi everyone,
> 
> Back with another sea ice question (well, two), specifically about calculating sea ice export. Apologies again for not being able to figure this out from the documentation.
> 
> I'm currently calculating ice export as sea ice load (given in kg/m2) * meridional velocity in the surface ocean layer (m/s) * dx across the grid cell (m). This should give kg/s of ice exported out of the northern face of any grid cell (but I believe I'm wrong about the ocean surface velocity - see question 2).
> 
> My two questions are:
> 
> (1) Does the "sIceLoad" diagnostic ("sea-ice loading (in Mass of ice+snow / area unit)") need to be multiplied by "SIarea" ("fractional ice-covered area [0-1]") in every grid cell, or does it already take this into account?
> 
> (2) I'm realizing that it's perhaps incorrect to use the ocean model's meridional velocity in the surface layer in this calculation, since for example wind can move sea ice too. Should I instead be using the "SIvice" diagnostic ("SEAICE merid. ice velocity, >0 form South to North")? Does this give the net movement of sea ice from both winds and ocean currents?
> 
> Thank you very much,
> Maddie Shankle
> 
> 
> 
> 
> 
> <Outlook-2vh40bnf.png>Maddie Shankle
> PhD Student, Paleoceanography
> School of Earth & Environmental Sciences   
> Bute Building, Queen's Terrace
> St Andrews, Fife, KY16 9TS
> 
> mgs23 at st-andrews.ac.uk 
> www.st-andrews.ac.uk
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