[MITgcm-devel] status

[Menemenlis, Dimitris (3248)]

Gael, thank you for message. I know that your two scenarios were the starting point of discussions for ice age tracer but I don't yet know what Pierre decided to implement as I did not take part in discussions about this yesterday.

Could you remind me what "extensive" and "intensive" mean. Do they mean area-based as opposed to volume-based? Eventually we should implement both. The first is more directly observable while the second seems to be a more meaningful measure of age.

A third useful age diagnostic, down the road, will be to use several simultaneous age tracers that categorize fraction of first year ice, second year ice, etc., in each cell.

The eventual hope is that we will be able to use one or more of the age diagnostics to better parameterize sea ice properties like drag, thickness distribution, and ice strength. 

Dimitris Menemenlis
818-625-6498

On Feb 24, 2011, at 1:01 AM, "Gael Forget" <gforget at MIT.EDU> wrote:

> Hi Dimitris and Patrick,
> 
> a few thoughts regarding ice tracers (salinity and age for now). 
> 
> My recollection is that there are currently two issues regarding the age tracer:
> (1) it is advected as extensive, whereas it is otherwise treated as intensive.
> (2) the lack of detail regarding the effect of individual growth/melt terms on age.
> 
> With regard to generic ice tracers a choice will have to be made between 
> extensive (as in SEAICE_SALINITY) and intensive (as in SEAICE_AGE).
> I wrote down the two scenarios equations for Pierre so he knows how to 
> proceed either way for the age tracer. I dont have a strong preference but 
> 'intensive' would imply  a division by HEFF during advection (as opposed 
> to diagnostics) that could prove problematic. So I am wondering whether 
> it would it be good time to switch SEAICE_AGE to extensive. 
> 
> Cheers,
> Gael