[MITgcm-devel] Unrealistic low SST with SEAICE_GROWTH_LEGACY undef

[Jean-Michel Campin]

Hi Dimitris,

> ??? What should this package be called: pkg/ifreeze, pkg/frazil, other suggestions?
My vote on the new pkg name (among the 2 you proposed): "pkg/frazil" ?
or outside your list "pkg/frazil_ice" (with variable short name "frazil" ?)

And regarding this:
> A 2D array containing negative heat in "Joules" will be generated,
I think it's better in Watts (and even more convenient in W/m^2),
so that when using a different ime-step for each level, we have 
a better chance to do it right. And the division by rAc (to have it
in W/m^2) would be more convenient since all the current 2-D heat-related 
fluxes are in W/m^2.

Regarding Gael's comments, I don't see the need to follow the steps 
he proposed (but may be I am missing something, since I don't understand
the connection with "convective adjustement rather than kpp" neither
with atmospheric heat flux), and I would not starts with the plug-in 
in pkg/thsice since there is no option in thsice to disable the
formation of seaice when SST goes below freezing.

Cheers,
Jean-Michel

On Wed, Feb 15, 2012 at 09:09:11AM -0800, Menemenlis, Dimitris (3248) wrote:
> Gael, thanks for comments.  Some answers below:
> 
> Regarding the name, I can use "pkg/interior_freeze" for package but need
> a shorter name (ifreeze?) for flags, variable names, and subroutine names.
> 
> I agree that this package need to work independently of the other ice packages.
> Modifying any of the sea ice packages is a separate step.
> What Ian and I envisioned is following sequence:
> 
> 1. Call iFREEZE_INTERIOR
>     to adjust interior temperature to freezing point and to compute negative heat anomaly that rises to surface.
> 
> 2. Call all the other ice package (freeze_surface, seaice, thsice, icefront, shelfice, ...)
>     which can (but do not have to) operate on this negative heat anomaly.
> 
> 3. Call iFREEZE_SURFACE
>     which will use any residual negative heat left over after the other ice packages are done,
>     to cool SST or sea water immediately below ice shelves.
> 
> The above sequence will achieve what you describe below, but it leave open the possibility for
> the ice packages to do fancier stuff with this negative heat anomaly, if they wish to do so.
> 
> Dimitris Menemenlis
> 
> On Feb 15, 2012, at 8:26 AM, Gael Forget wrote:
> 
> Hi Dimitris,
> 
> I dont have a strong preference regarding names but interior_freeze may be
> just fine (item 1) and item 3 likely should be done before anything else.
> 
> As far as item 2 the new package should be made to work independently of pkg/thsice and pkg/seaice first (and of kpp please).
> Basically I suggest you start with
> => A 2D array containing negative heat in "Joules" will be generated that will be added to Qnet.
> => allowFreezing rather than more complex ice models, and convective adjustement rather than kpp.
> It would be nice to add a switch to decide whether the needed heat should be taken from the ocean first layer (as it is now I believe)
> or in the atmosphere (where your plan takes at least some of it). And it should be possible for the user to back out the
> ocean conservation of heat (or the lack thereof) using pkg/diagnostics. Those points seem like obvious pre-requisites
> to a discussion of whether a refined integration in ice models is worth it and of interest. If you decide to forego those intermediate steps,
> I would suggest you go all the way and start with pkg/thsice rather than pkg/seaice -- with the better ice conservation principle that is.
> 
> Cheers,
> Gael
> 

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