[MITgcm-support] Icefront returnin NaN based on topology.

[Martin Losch]

Harry,

I think it would be useful to know about the details of the configuration. It would also help to have the illustrative example that you describe as a “code” and “input” directory (I am assuming it’s a very small domain), including the matlab (?) file to generate the different input files.

Martin

On Feb 16, 2014, at 2:41 AM, Harry A <gmtonys3 at hotmail.com> wrote:

> Hi Everyone
> 
> I'm working on a model including a glacier, so I've been implementing the Icefront package to add this functionality.
> However, when I am setting up the topology of my submerged ice, I've had NaN results for all outputted velocities and temperatures turning up at strange times.
> 
> I have a bottom topology over my whole domain with closed boundaries (Depth = 0 all around) To begin with, I just made a 3x3 grid in the middle of my domain ice, but depending on where I place it the model with either return all NaN or return good results. It seems even if I make this ice shallow (say 10 meters deep in 100m water) or as deep as the water at the certain location, or even deeper, I still get failure with some locations and not others.
> 
> To highlight the problem, one example is I can make a single grid point in the middle of my domain have ice 70.4952 meters deep (with the bathymetry file being exactly 70m deep in that location) and it will work, however if I make this 70.4953 or 70.4951 the model returns all NaNs.
> 
> Does anyone have any idea what could be causing these issues? Am I correct in saying the Ice depth file for Icefront ( ICEFRONTdepthFile) meant to be positive values ranging from 0 up to the depth of water at any given grid point ? And the ICEFRONTlengthFile should be the facial area of a grid element in the horizontal direction, so If I'm using dX=50, dY=50, dZ = 15, it should be 15*50 = 750?
> 
> Thanks for any assistance, I've been running through matlab scrips generating ice topologies for 6 hours now and there seems to be almost no rhyme or reason as to why some situations fail and some work just fine...
> 
> Harry
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