[MITgcm-support] Ross Sea simulation crash

[Pochini, Enrico]

Hi Jody,

Your reply ended up in spam, I noticed only now..
Eventually I managed to run it with a 5 s timestep. It was indeed a
stability issue; I have switched to a cartesian grid and things are working
now with a reasonable (150 s) time step.

Thank you and best regards,

Enrico

Il giorno mar 22 ott 2019 alle ore 18:05 Jody Klymak <jklymak at uvic.ca> ha
scritto:

> Hi Enrico,
>
> You can check the cfl criteria by looking at STDOUT.0000 (advu_cfl,
> advw_cfl etc). You don’t say anything about your vertical resolution, but
> if it is fine enough to use non-hydrostatic then you are quite possibly
> violating the CFL criteria in the vertical velocity.
>
> For testing purposes you may want to turn nonHydrostatic off (and maybe
> consider whether 0.5 degree runs can properly represent non-hydrostatic
> effects).  That may not help your cfl criteria, but the model will run
> faster.
>
> Cheers,   Jody
>
> On 22 Oct 2019, at 06:53, Pochini, Enrico <epochini at inogs.it> wrote:
>
> Dear MITgcm support group,
>
> I'm trying to develop a model of the Ross Sea for my PhD. Until now I've
> generated the grid and I've started testing it with constant atmospheric
> forcing, boundary conditions, and initial conditions, but I'm crashing a
> few kilo-seconds after initialization.
>
> To generate it I followed what is written in this page:
>
> https://github.com/knaughten/mitgcm_python/wiki/Creating-a-new-MITgcm-domain#grid
>
> However even minimal runs with disabled SHELFice, OBCS packages, imposing
> no surface forcing, with uniform initial conditions, still it develops
> instabilities and crashes.
>
> I'm absolutely new to MITgcm and ocean modeling and I would need your help
> to understand what is causing the issues, in particular if the bathymetry
> has some pathologies or the (spherical) grid violates CFL somewhere .. (?)
> I'm using 150 seconds timestep, 0.5 degree grid.
>
> I've attached four minimal test outputs, with and without ice shelf, with
> and without smoothing of ice shelf draft and bathymetry. The number with
> the file is the last iteration printed.
> Thank you.
>
> Best regards,
>  file_support.tar.gz
> <https://drive.google.com/a/inogs.it/file/d/1SM5mtzq3WgF61EbLh4404N5cz3czIuSI/view?usp=drive_web>
>
> Enrico Pochini
>
> PhD student, University of Trieste, Italy
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>
>
> --
> Jody Klymak
> http://web.uvic.ca/~jklymak/
>
>
>
>
>
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