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1. Add a row for your new grid in the appropriate table below

2. Add the grid files to inputdata/share/meshes following the directions at /wiki/spaces/ED/pages/707002387.

3. Create a pull request making your grid available. The changes should be limited to what is needed to support the new grid as outlined below.

4. Modify cime_config/config_grids.xml to define the new grid

5. Modify cime_config/config_grids.xml to specify domain file paths

6. Modify cime_config/config_grids.xml to specify mapping file paths (only for bi- and tri-grid)

7. Modify components/eam/bld/config_files/horiz_grid.xml to specify the number of columns

8. Modify components/eam/bld/namelist_files/namelist_defaults_eam.xml to specify namelist defaults specific to the new grid. Typically values that need new defaults are:

   1. ncdata - the atmospheric initial condition

   2. bnd_topo - topography

   3. drydep_srf_file surface dry deposition of aerosols (MAM)

   4. mesh_file - grid definition file in exodus format

   5. se_ne - set to zero for RRM

   6. dtime - dynamics/physics coupling interval

9. For certain configurations, especially the older preqx dycor option, you may need to modify the following parameters in components/eam/bld/namelist_files/namelist_defaults_eam.xml

   1. se_tstep

   2. nu

   3. nu_top

   4. nu_div

   5. hypervis_scaling

   6. hypervis_subcycle_tom

   7. hypervis_subcycle

10. Modify components/clm/bld/namelist_files/namelist_defaults_clm4_5.xml to specify land input files needed for the new grid (may not be needed for scenarios that do modify the land grid)

    1. finidat - land model initial condition

    2. fsurdat - input data describing surface types

11. Optional - modify cime/config/e3sm/allactive/config_pesall.xml to add a new PE layout for your grid

12. Optional - modify cime_config/tests.py to add a test for the new grid. RRM tests should only be added to specific test suites, such as e3sm_rrm.

Quasi-Uniform cubed-sphere grids (for reference)

Conventional High-Resolution Grids

Grid Name	Target Fine Resolution	Target Coarse Resolution	Goals in mesh creation	Link to mesh graphic	Grid metrics	Validation	Contact Person
v2 North American RRM northamericax4v1.g	atm/land: 25 km (ne120) ocean/ice: 14 km	atm/land: 100 km (ne30) ocean/ice: 60 km		See figures in the paper	Max Dinv-based elem distortion: 3.76 area based dx: min=17 km max=117 km	Described in Tang et al., (GMDD 2022)	Qi Tang
v2 Antarctic RRM antarcticax4v1.g	atm/land: 25 km (ne120)	atm/land: 100 km (ne30)		/wiki/spaces/ED/pages/934314314		TBD	Qi TangWuyin Lin
CONUS Extremes-Optimized RRM (HyperFACETS)	atm/land: 25 km (ne120)	atm/land: 100 km (ne30)	28km over CONUS and Atlantic TC region; 55km over eastern Pacific to better capture ARs			TBD	Paul Ullrich
arcticx4v1pg2	atm/land: 25 km (ne120)	atm/land: 100 km (ne30)			elem distortion: 4.26 area based dx: min=23 km max=125 km	TBD	Ben Hillman

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