docs

doc/source/user_guide/ug_case_settings.rst

@@ -307,6 +307,7 @@ grid_nml
    "``grid_file``", "string", "name of grid file to be read", "'unknown_grid_file'"
    "``grid_format``", "``bin``", "read direct access grid and kmt files", "``bin``"
    "", "``nc``", "read grid and kmt files", ""
+   "", "``mom_mosaic``", "read grid in mom mosaic format and kmt files", ""
    "``grid_ice``", "``B``", "use B grid structure with T at center and U at NE corner", "``B``"
    "", "``C``", "use C grid structure with T at center, U at E edge, V at N edge", ""
    "``grid_ocn``", "``A``", "ocn forcing/coupling grid, all fields on T grid", "``A``"

doc/source/user_guide/ug_implementation.rst

@@ -133,8 +133,10 @@ The user has several ways to initialize the grid, which can be read from
 files or created internally. The *rectgrid* code creates a regular rectangular 
 grid (use the namelist option ``grid_type='rectangular'``). The *popgrid* and *popgrid_nc* 
 code reads grid lengths and other parameters for a nonuniform grid (including tripole
-and regional grids). 
-The input files **grid_gx3.bin** and **kmt_gx3.bin** contain the
+and regional grids). The *mom_mosaic* code reads grids for a nonuniform grid defined 
+in the mom mosaic (supergrid) format.
+
+For the *popgrid* formats, the input files **grid_gx3.bin** and **kmt_gx3.bin** contain the
 :math:`\left<3^\circ\right>` POP grid and land mask;
 **grid_gx1.bin** and **kmt_gx1.bin** contain the
 :math:`\left<1^\circ\right>` grid and land mask, and **grid_tx1.bin** 
@@ -149,6 +151,15 @@ and ANGLE variables. If the variables exist, ANGLET, TLON and TLAT will also be
 read from a netcdf grid file. The kmt (mask) netcdf file needs a variable named 
 kmt or mask, set to 0 for land and 1 for ocean.
 
+For the *mom_mosaic* formats (``grid_type='mom_mosaic'``), a grid file following
+the MOM mosaic (supergrid) convention as generated by `FRE-NCTools <https://github.com/NOAA-GFDL/FRE-NCtools>`_
+ and described in `this short summary <https://gist.github.com/adcroft/c1e207024fe1189b43dddc5f1fe7dd6c>`_ 
+is required. CICE derives the required grid variables to match the grid implementation 
+in MOM6. All lat/lon and grid lengths are read from the file. Cell areas for A & B grid 
+cells are loaded from the file, and grid lengths for C grid cells are calculated internally.
+Rotation angles for cells are also calculated interally. All calculations match the methods
+used in MOM6 for consistency.
+
 The input grid file for the B-grid and CD-grid is identical.  That file
 contains each cells' HTN, HTE, ULON, ULAT, and kmt value.  From those
 variables, the longitude, latitude, grid lengths (dx and dy), areas,