...

On derecho, checkout a CESM3 beta tag (that uses ctsm5.2).  It is recommended the source code is cloned into your work (or scratch, if necessary; you might run out of space in home) directory where sufficient storage is available. CESM3 has replaced manage_externals with git-fleximod, which requires the following commands:

...

Below, $CESMCODE refers to yourcesm3_0_beta01 directory.

CCS_CONFIG

1. Add an entry for your new ESMF mesh file in <cesm>/ccs_config/component_grids_nuopc.xml

For this grid:

  <domain name="ne0np4.Nanjing.ne30x8">
    <nx>60482</nx> <ny>1</ny>
    <mesh>/glade/work/emmons/tutorial_Nanjing/ne0np4.Nanjing.ne30x8/grids/Nanjing_ne30x8_np4_MESH.nc</mesh>
    <desc>ne0np4.Nanjing.ne30x8 is a Spectral Elem 1-deg grid with a 1/8 deg refined region over east China:</desc>
    <support>Test support only</support>
  </domain>

2. Add a grid alias entry in <cesm>/ccs_config/modelgrid_aliases_nuopc.xml:

  <model_grid alias="ne0Nanjingne30x8_ne0Nanjingne30x8_mt12" not_compset="_POP">
    <grid name="atm">ne0np4.Nanjing.ne30x8</grid>
    <grid name="lnd">ne0np4.Nanjing.ne30x8</grid>
    <grid name="ocnice">ne0np4.Nanjing.ne30x8</grid>
    <mask>tx0.1v3</mask>
  </model_grid>

...

> cd $CASEROOT
> ./case.setup

Add to user_nl_cam:

 ncdata = '/glade/work/emmons/tutorial_Nanjing/ne0np4.Nanjing.ne30x8/cami-mam4_0000-01-01_ne0np4.Nanjing.ne30x8_L32_c240809.nc'
 bnd_topo = '/glade/work/emmons/tutorial_Nanjing/ne0np4.Nanjing.ne30x8/topo/topo/Nanjing_ne30x8_gmted2010_modis_bedmachine_nc3000_Laplace0100_noleak_20240729.nc'
 drydep_srf_file = '/glade/work/emmons/tutorial_Nanjing/ne0np4.Nanjing.ne30x8/atmsrf/atmsrf_ne0np4.Nanjing.ne30x8_240809.nc'
 se_refined_mesh = .true.
 se_mesh_file = '/glade/work/emmons/tutorial_Nanjing/ne0np4.Nanjing.ne30x8/grids/Nanjing_ne30x8_EXODUS.nc'

...

Set the timestep based on recommended value in: https://github.com/ESMCI/Community_Mesh_Generation_Toolkit/blob/master/VRM_tools/Docs/CAM-tsteps-inic-for-newgrids_v0.pdf

./xmlchangeATM_NCPL=384

Add to user_nl_clm:

fsurdat = '/glade/work/emmons/tutorial_Nanjing/ne0np4.Nanjing.ne30x8/land/surfdata_Nanjing_ne30x8_SSP3-7.0_1979_78pfts_c240809.nc'
flanduse_timeseries = '/glade/work/emmons/tutorial_Nanjing/ne0np4.Nanjing.ne30x8/land/landuse.timeseries_Nanjing_ne30x8_SSP3-7.0_1979-2026_78pfts_c240809.nc'

...

Set up a CAM-chem case for production

Create a case with FCnudged compset

...

> /glade/work/emmons/cesm_src_derecho/cesm3_0_beta01/cime/scripts/create_newcase --case /glade/work/emmons/tutorial_Nanjing/cases/f.e3beta01.FCnudged.Nanjing_ne30x8.01 --res ne0Nanjingne30x8_ne0Nanjingne30x8_mt12 --compset FCnudged  --run-unsupported --project AACD0004 --pecount 2048

Regrid IC file

You will need to regrid a previous CAM-chem IC file to your grid (to use for ncdata in user_nl_cam).  If you have an IC file on a Finite Volume grid (f09) use 'interpic' as shown above.  If starting from a file on ne30 grid, use the ncl script at: https://github.com/NCAR/IPT/tree/master/Initial_conditions

A sample script for regridding a f09 CAM-chem file to the new grid is: /glade/work/emmons/tutorial_Nanjing/ne0np4.Nanjing.ne30x8/inic/interpic_script_camchem_Nanjing.sh

Regrid emissions files to your grid

Regrid meteorology (MERRA2 or GEOS-FP) files to your grid

Update user_nl_clm

Use the CLM restart file from your CAM spinup for finidat in user_nl_clm.

Update user_nl_cam

If simulating post-2015, update lower boundary conditions file:

 flbc_file = '/glade/p/cesmdata/cseg/inputdata/atm/waccm/lb/LBC_17500116-25001216_CMIP6_SSP585_0p5degLat_c20200824.nc'

Add list of emissions files on new grid (srf_emis_specifier and ext_frc_specifier)

Update sea surface temperature (SST) file

...

You will need to regrid a previous CAM-chem IC file to your grid (to use for ncdata in user_nl_cam).  If you have an IC file on a Finite Volume grid (f09) use 'interpic' as shown above.  If starting from a file on ne30 grid, use the ncl script at: https://github.com/NCAR/IPT/tree/master/Initial_conditions

A sample script for regridding a f09 CAM-chem file to the new grid is: /glade/work/emmons/tutorial_Nanjing/ne0np4.Nanjing.ne30x8/inic/interpic_script_camchem_Nanjing.sh

Also, regrid emissions and met files to your grid.

Use the CLM restart file from your CAM spinup for finidat in user_nl_clm../xmlchange SSTICE_DATA_FILENAME='/glade/p/cesmdata/inputdata/atm/cam/sst/sst_HadOIBl_bc_1x1_1850_2021_c141021.nc'
./xmlchange SSTICE_YEAR_END=2021