[MITgcm-devel] Add sea ice surface forcing to pkg/seaice

[Dimitris Menemenlis]

I have added snowPrecip forcing for pkg/seaice:

           HSNOW(I,J,bi,bj) = HSNOW(I,J,bi,bj) +
     &          convertPRECIP2HI*ICE2SNOW*snowPrecip(i,j,bi,bj)

This is a quick-and-dirty way to simulate collapse of tidewater glaciers.
Contrary to Precip, snowPrecip is not multiplied by sea ice
concentration (AREA).  It falls as snow even on top of open water,
helps cool SST, and eventually through "SEAICEuseFlooding"
it generates some sea ice.  

#define SEAICE_VARIABLE_SALINITY
is needed so that the useFlooding sea ice is added as fresh-water sea ice.

Dimitris Menemenlis

On Apr 19, 2012, at 9:10 AM, Torge Martin wrote:

> In general Martin is right, I think. However, for two reasons Dimitri's approach seems to be a reasonable simple solution for now:
> 1) MITgcm does not have an iceberg model component, for example as described in Martin & Adcroft, 2010 ;-)
> but
> 2) MITgcm's sea ice model features variable salinity, right?
> 
> So, to first order icebergs, in particular "small" ice blocks (not giant tabular icebergs) feel basically the same dynamic forcing as sea ice, i.e. wind, ocean currents and some internal stress when locked in the sea ice cover/ice melange in front of an outlet glacier. There is no harm to let this land ice drift with the sea ice. We just need to consider that glacier ice is freshwater and hence reduces the average salinity of the "sea ice" in any grid cell where the calving flux enters the ocean grid.
> 
> Yes, the glacier ice would probably melt at a different rate than the surrounding sea ice but melting of (small) icebergs is not well understood nor constrained by observations, yet.
> 
> -Torge
> 
> On Wed, Apr 18, 2012 at 11:15 PM, Martin Losch <Martin.Losch at awi.de> wrote:
> A piece of a tidewater glacier is not sea-ice but an ice-berg, is it? Different structure, different salinity, etc. does it really make sense to add this type of ice to sea-ice, which is a quasi-continuous medium? I am not sure if this a sensible thing to do.
> 
> Martin
> 
> On Apr 18, 2012, at 8:16 PM, Menemenlis, Dimitris (3248) wrote:
> 
> > I plan to add capability to "add" sea ice to pkg/seaice as a surface forcing, e.g., as would happen when a tidewater glacier collapses.
> >
> > Any objections, suggestions, requests?  Maybe capability is already partly or fully there? I haven't looked at seaice code in some time.
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