[MITgcm-devel] Re: KPP subgrid-scale mixing

[Dimitris Menemenlis]

Hi Andrea, I am moving discussion to MITgcm-Devel list.

I think that there is definitely an impetus to do something about representation 
of convection due to salt rejection under sea ice.  I suspect that treatment of 
salt rejection may in part be responsible for CS510 solution problems both in 
the Arctic and in the Southern Ocean.

As a possible alternative (or temporary fix) to a full blown KPP-sub-grid-scale 
parameterization, I could implement the salt rejection scheme of Duffy, Eby, and 
Weaver (GRL 1999, vol 26, pages 1739-1742).  This scheme adds "saltFlux" into 
several layers at the same time, rather than in the surface level only, based on 
a density-difference criterion.  It is similar in some ways to the way shortwave 
radiation is currently treated but without the exponential decay.

Does anyone on the devel list have experience with the Duffy et al. scheme or 
alternative suggestions?

Dimitris


> hi dimitris,
> 
>> Hi Andrea, I am wondering whether you did pursue your KPP sub-grid scale mixing idea?  An Nguyen and I are seeing some issues with salt rejection by sea ice that may possibly be helped by a subgrid scale convection parameterization of the type you described when we last spoke.  Cheers, Dimitris
> 
> the short answer is 'no'.
> 
> (now you can stop reading if you want....)
> the long answer is that i started to set stuff up to do it,
> and what i did to the code broke taff big time. so j-m came behind
> me and took it all out..... but martin and i did discuss this at some length, and the strategy for doing this was mapped out. we just
> never pursued it. is there an impetus to pick it up again? (i have
> cc'd martin on this to see if he has any thoughts?)
> 
> 
> take care,
> andrea