Implement new CISM grids for AIS and GrIS

[hgoelzer]

Purpose:
We will use new grids for CISM3 that are aligned with the ISMIP6/7 grids for both ice sheets.

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Description:
Here the grid description from the ISMIP wiki in words:
GrIS: Polar stereo-graphic projection with standard parallel at 70° N and a central meridian of 45° W (315° E) on datum WGS84 (EPSG3413 projection). The lower left cell center is at (-720,000 m,-3,450,000 m) with nx=1,681 and ny=2,881 cells in x and y-direction at full 1 km positions (xmin = -720 km, xmax = +960 km, ymin = -3,450 km, ymax = -570 km).
AIS: Polar stereo-graphic projection with standard parallel at 71° S and a central meridian of 0° W on datum WGS84 (EPSG3031). The lower left corner is at (-3,040,000 m, -3,040,000 m) and the upper right at (3,040,000 m, 3,040,000 m). The output should be submitted on a resolution adapted to the resolution of the model and can be 32km, 16 km, 8 km, 4 km, 2 km or 1 km.

Grid description files (CDO netcdf format) are available, e.g. at
/nird/datalake/NS8085K/CISM/Database3/Grid

Preliminary input data is available at
GrIS: /nird/datalake/NS8085K/CISM/GrIS/Database7/Obs
AIS: /nird/projects/NS11016K/CISM/AIS/Input

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[mpetrini-norce]

General steps necessary to implement new CISM grids in a fully coupled NorESM run:

1. Create SCRIP files (grid description files) and CISM input files;

2. Create GLC MESH files needed from NorESM to calculate mappings;

3. When setting up a new case,
   (a) specify new GLC MESH in env_run.xml (./xmlchange GLC_DOMAIN_MESH="new_mesh_file";
   (b) specify new CISM input files and updated north-south nodes and east-west nodes in user_nl_cism
   cisminputfile='new_input_file'
   nsn=ny
   ewn=nx

[mpetrini-norce]

Application: implementing new CISM grids for AIS and GrIS in a fully coupled NorESM run - documenting steps and issues

1. Create SCRIP files (grid description files) and CISM input files;

@hgoelzer, can you describe the steps/scripts necessary to generate SCRIP files and input fields (different files for different groups of variables such as geometry, geothermal heat flux, surface,...)?

1a. SCRIP files

1b. Input fields (geometry, geothermal heat flux, surface,...)

• WARNING Found negative ice thickness values in Antarctic input files (in the field family 'geometry'). @hgoelzer will check this and correct when it's solved.

1c. In a fully coupled run, all desired CISM input variables should be stored in one file for each ice sheet domain. We created new scripts that are doing this, based on the specific dataset that the user would like to use:
Antarctica: /projects/NS11022K/mpet/datasets/cism_newgrid_inputfiles/ant/create_inputfiles.ncl
Greenland: /projects/NS11022K/mpet/datasets/cism_newgrid_inputfiles/gris/create_inputfiles.ncl
Output from this script can be immediately used as a CISM input file.

• Replace negative ice thickness correction from the script for Antarctica after the issue in 1b is solved.

2. Create GLC MESH files needed from NorESM to calculate mappings; (instructions from @gunterl)

1a The starting point of this step are the SCRIP files (grid description files), which can be found here
Greenland:
Antarctica:

2b Load ESMF, find the path to the binaries, list the binaries.

[mvdebolskiy]

@mpetrini-norce you don't need mapping files for nuopc. You just need meshes.

[hgoelzer]

This is done, closing the issue.