[MITgcm-devel] pkg/seaice wish list

[chris hill]

Hi Martin,

  A break - I'm shocked!
  What is the status of the documentation/paper on the seaice? Patrick 
and I would be happy (actually I haven't checked this with Patrick!) to 
spend a bit of time trying to get the technical documentation up to date 
in the manual. If you have anything we can start from that would be good.

Chris
Martin Losch wrote:
> Hi,
> 
> after all these changes during the last week(s), I would like to take a 
> break from this seaice frenzy, but not without writing down a few thing 
> that still require some attention, technically speaking:
> 
> 1. Defaults: currently, the seaice ice package has a few unfortunate 
> defaults (they affect only seaice_growth and seaice_advdiff and not the 
> dynamics):
> - SEAICEadvSnow = .false. (changing this will change lab_sea again)
> - flooding should probably be turned on by defaut (currently #undef 
> ALLOW_SEAICE_FLOODING and SEAICE_flooding = .false., I suggest removeing 
> the CPP-flag, if TAF complies, and setting SEAICE_flooding = .true., 
> (also changes lab_sea)
> - #undef SEAICE_MULTICATEGORY should probably turned on by default. 
> That's a standard feature of ice models (modifies lab_sea)
> - comment in these as default in seaice_growth:
> CML#ifdef SEAICE_EXTERNAL_FORCING
> CMLC     this seems to be more natural as we do compute the wind speed in
> CMLC     pkg/exf/exf_wind.F, but it changes the results
> CML          UG(I,J) = MAX(SEAICE_EPS,wspeed(I,J,bi,bj))
> CML#else
> [...]
> CML#endif
> 
> 2. time stepping variables: I would like to get rid of these 3 time 
> levels for HEFF, AREA, UICE/VICE. They make life miserable and increase 
> the number of exchange unnecessarily. But this would also mean that the 
> B-grid code would be really out of date and unusable (unless that is 
> sorted out as well). It also means that advection with leap-frog is no 
> longer possible (currently it's only possible with the default advection 
> scheme = 2 and no advection of snow, so that's not really a loss)
> 
> 3. related to 2: sort out the pickup files. We don't need all time 
> levels in the pick up files (in fact we need only one) and we don't need 
> all of these variables in there, e.g. YNEG could definitely be a local 
> variable in seaice_growth. the pickup could be devided into a dynamics 
> and a thermodynamics pickup, since we only need the dynamics, if we want 
> to use seaice+thsice.
> This way we could also have netcdf pickups more easily (possibly).
> 
> 4. sort out spurious exchanges especially in seaice_model
> 
> 5. remove the spurious seaice forcing "package" (along with some 
> diagnostics, e.g. UWIND/VWIND)
> 
> 6. Improve vectorisation of seaice_lsr/evp
> 
> 7. add some sanity test (as Chris has suggested earlier). I have two 
> tests for the dynamics only, one is based on Hunke, JCP (2001), maybe in 
> the contrib area?
> 
> 8. add simple and exchangable/tunable ridging algorithms (in a 
> transparent way, not as it is done now in seaice_growth, and 
> who-knows-where in thsice).
> 
> 9. Finally, find a way to give the MITgcm a more transparent way of 
> doing sea ice: that is, either merge seaice and thsice (which I prefer) 
> or separate seaice into a dynamics and a thermodynamics package
> 
> ... anything else? Oh yes, documentation, coming soon (o:
> 
> Martin
> 
> 
> 
> 
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