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

[Stephen Hunter [EAR]]

Thank you Jean-Michel,

Those grid files worked well. One more question if you don’t mind -

If I wanted to create these grid files myself for an arbitrary CS grid (eg. cs64), is there a way to do this via Matlab/Python? (I assume the otters grid sets within ecco_for_las/version_4/grids/grids_input/cs_nostretch/ don’t have the rotation angle fields either)

Kind regards,

Stephen

> On 27 Feb 2020, at 16:39, Jean-Michel Campin <jmc at mit.edu> wrote:
> 
> 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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