[MITgcm-support] Problem with CS96 model set-up

[Jean-Michel Campin]

Hi Stephen,

I would recommand to try to use the grid files from there, under CVS:
 http://wwwcvs.mitgcm.org/viewvc/MITgcm/MITgcm_contrib/dyncore_ASP/csgrids/ref_96
with longitude in [-180,+180] or, if you prefer to have longitude in [0,+360], then 
you can take grid files directly from there, under CVS:
 http://wwwcvs.mitgcm.org/viewvc/MITgcm/MITgcm_contrib/dyncore_ASP/csgrids

These sets of grid have been used, and they do contain the rotation-angle fields which 
might be missing in the grid files you tried to use.

Cheers,
Jean-Michel

On Thu, Feb 27, 2020 at 03:28:27PM +0000, Stephen Hunter [EAR] wrote:
> Dear MITgcm Support Team,
> 
> 
> 
> I am trying to create a cube-sphere (CS96) MITgcm Ocean model setup which I plan to force with climatology derived from an Atmosphere-only GCM in a way similar to ECCO (but without the adjoint package and CS96 rather than LLC90 grid). I believe (well, hope) that I can create correctly the appropriate bathymetry and forcing binary files.
> 
> 
> 
> My problem lies in the initialisation of the model, in particular regarding the grid setup. I have searched the manual and verification experiments for code but I am still unsure how to create the grid_cs96_face00[1-6].bin files. Fortunately, I found a set within http://mit.ecco-group.org/datasets/ecco_for_las/version_4/grids/grids_input/cs_nostretch/cube_96/, which appear to be the correct size (8bytes*(96+1)*(96+1)*16records = 1204352 bytes). I have renamed the files to grid_cs96.face001.bin etc. and set up my input/data to see read them. Additionally, I can read these grid_cs96.face00[1-6].bin binaries using Matlab GCMfaces and can create a mygrid structure (which I have used to create the bathymetry.bin).  I believe these binary grid files are what I need. I have within input/data
> 
> 
> 
> # Gridding parameters
> 
> &PARM04
> 
> horizGridFile='grid_cs96',
> 
> usingCurvilinearGrid=.TRUE.,
> 
> 
> 
> On running, the model fails with  the following error
> 
> forrtl: severe (36): attempt to access non-existent record, unit 9 file [my_full_path]/build/grid_cs96.face001.bin
> 
> 
> 
> I have searched MITgcm-support and it seems the model is trying to access records that are not within the grid_cs96.face00[1-6].bin files - which suggests an incorrect SIZE.h file.  I have tried numerous configurations of SIZE.h. A simple case I have for SIZE.h which (I believe) sets up a CS topology with 24 tiles running on 6 processors.
> 
> 
> 
>       PARAMETER (
> 
>      &           sNx =  48,
> 
>      &           sNy =  48,
> 
>      &           OLx =   4,
> 
>      &           OLy =   4,
> 
>      &           nSx =   4,
> 
>      &           nSy =   1,
> 
>      &           nPx =   6,
> 
>      &           nPy =   1,
> 
>      &           Nx  = sNx*nSx*nPx,
> 
>      &           Ny  = sNy*nSy*nPy,
> 
>      &           Nr  =  50 )
> 
> 
> 
> Looking at the cs32 verification experiments which I can run, the experiment uses grid_cs32 .face00[1-6].bin files that are 156816bytes in size (e.g. within global_oce_cs32/input_fields/) whereas I would expect them to be 8bytes*(32+1)*(32+1)*16records=139392 bytes. Hence I think that I am misunderstanding something. I believe that my compiler optfile is correct (the verification experiments work).
> 
> 
> Kind regards,
> Stephen Hunter
> 
> School of Earth & Environment
> University of Leeds
> 

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