[MITgcm-devel] upcoming changes in seaice_growth.F

[Gael Forget]

Hi Ian and co.,

below I report what Ian and I discussed at the ECCO2 meeting,
which I just got started with seaice_growth.F rev.121 (see below).  

So, to complete the 'merging' process, we planned the following:
1) a few changes in the EVOLUTION branch
        1.1) reduce the areaMin default
        1.2) always include a_QSWbyATM_cover in QNET
        1.3) use Ian's heff_star sqrt formula in heffActual
        1.4) add the Winton (?) formula for flooding
	1.5) add a check for the areaMax range
2) remove code duplicates and restore the integrity of the two branches structure
   (EVOLUTION: with Ian's codes // LEGACY: for backward compatibilty)
3) add somewhere in the code (SEAICE_OPTIONS.h or seaice_check.F may be)
   the combination of CPP options that is advised for adjoint runs.

Once we complete that, I would also like to open up a discussion on the seaice_growth
diagnostics, which I think can also use some review/clean up(?)/complements(?).

In seaice_growth.F rev.121, I did 1.2) and updated the global_ocean.cs32x15 results
accordingly. I also got started with 2) and updated the 1D_ocean_ice_column
SEAICE_OPTIONS.h accordingly (no change in results).

With regard to 1.2) I felt it was best not to do it in the LEGACY branch,
since it would affect backward reproductibility. Makes sense, right?

With regard to 2) I left the FENTY_AREA_EXPANSION_CONTRACTION part for later,
since 1.3) is a pre-requisite. Ian, you were going to check that using 0.05^2 rather 
than 0.1^2 in the heff_star sqrt formula is fine in adjoint mode. Is it?

With regard to 1.4) I argued at the time that we may as well replace the
flooding formula in the EVOLUTION branch (only). But may be we should
keep both and add a CPP option. Opinions?

With regard to 1.1) Ian argued at the time that we don't need
areaMin (old A22) to be a run time parameter. Opinions?
In any case we would leave the 0.15 default for the LEGACY branch.
For the EVOLUTION branch we talked about 10^-5 if I remember right.

Cheers,
Gael