[MITgcm-devel] Unrealistic low SST with SEAICE_GROWTH_LEGACY undef

[Martin Losch]

Hi Dimitris,

you are right: I am using SEAICE_gamma_t_frz=SEAICE_gamma_t, so I could try that. 

But my point is that with the non-legacy code this is not even necessary. The legacy code somehow produces very low temperatures, that then require some ad-hoc fixes (although I can think of a justification for having a very short gamma_t_frz). I think that we should be able to run the model without these fixes that cover up all sorts of problems (I am not saying that we should fix the legacy code, but that we should make sure that with the new code these things don't happen again. And I am afraid that they will, if we use some unclear parameterization as a rule).

Martin


On Feb 7, 2012, at 2:27 PM, Menemenlis, Dimitris (3248) wrote:

> Martin, I am assuming that the reason that you get such low temperatures with seaice-legacy code is because you do not set
> SEAICE_gamma_t_frz independently from SEAICE_gamma_t.  Please confirm.
> 
> Note the following comments in SEAICE_PARAMS.h:
> 
> C     SEAICE_gamma_t     :: Timescale for melting ice from a warm mixed layer (s),
> C                           3d = 259200s is a reasonable value, default=unset
> C     SEAICE_gamma_t_frz :: timescale for freezing ice from a cold mixed layer (s),
> C                           3h = 10800s is a reasonable value, default=SEAICE_gamma_t
> 
> Maybe we should change the default SEAICE_gamma_t_frz to be different (smaller) that SEAICE_gamma_t.
> What do you think?
> 
> Dimitris Menemenlis
> 
> On Feb 7, 2012, at 4:56 AM, Martin Losch wrote:
> 
>> As an example, with the seaice-legacy code, this safeguard does not prevent low temperatures (-5degC) in my configuration.
> 
> 
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