[MITgcm-support] seaice_salinity

[Dimitris Menemenlis]

> Right, it may not be the seaice model itself, the seaice dynamics  
> may be causing the ocean model to blow up. And it might be the  
> aspect ratio.  Unfortunately I don't really know when and where the  
> instability is occurring. The problem is the crash always takes at  
> least 14 days to occur.  So I really don't get that output....maybe  
> I can code something so that when the stop is called it writes the  
> final state.  I'll look into that.

if you know when the crash occurs, you could dump a pickup a few time  
steps before the crash and then restart with more output.

in all cases you should run with monitorfreq=1, so you can see how  
things evolve in STDOUT

> So do you have any hunches as to what is happening at what may cause  
> this.  Earlier you wrote,
> "The CS510 solution also has some very saline water in narrow fjords  
> around Antarctica.  I think what might be happening is that ice is  
> acting as a salinity pump, taking freshwater out of the fjord, when  
> ice dynamics are turned on, but there is no mechanism for flushing  
> the salty water out in the model ocean.  Let me know what you find.   
> D."
> The model is more stable with #undef SEAICE_SALINITY so perhaps this  
> is the case.  Is there anything I can further do to prevent this  
> "salinity pump".

this is counterintuitive.  SEAICE_SALINITY, if it works the way it's  
supposed to, will slow down the salinity pump (a little bit).  That  
is, the sea ice coming out of the narrow fjord will carry out a little  
salt with it, it will not be completely fresh.

One way to proceed, if you identify that narrow fjords cause your  
problem, would be to fill them in.  In any case they do not contribute  
anything useful to your solution since the model is not able to  
resolve processes in the fjords nor the exchanges with the Southern  
Ocean.

D.