CESM3.0a CTSM5.4 CASEROOT Variable Definitions

Name of land component

Flag to enable building the LILAC cap and coupling code

Tuning parameters and initial conditions should be optimized for what CLM model version and what meteorlogical forcing combination?
          Options for all combinations of CLM physics and atm forcing are given. The buildnml and namelist_defaults will narrow it down to the ones
          that have been tuned. The buildnml will also warn you if a tuning combination is based on another set.
          Atm forcing options:
               CRUJRA2024
               CRUJRA2024b
               CRUv7
               GSWP3
               CAM4.0
               CAM5.0
               CAM6.0
               CAM7.0
               QIAN   (not tuned)
               1PT    (not tuned)
               NLDAS2 (not tuned)
               ERA5   (not tuned)
          Other atm forcing options are invalid to run CLM and will result in an error.
    

Overall physics version to use.
    This sets the default values for many different namelist options.
    This is typically set by the compset.

Whether to use CMIP6 or CMIP7 fsurdat/landuse files.
    As of ctsm5.4 we do not have CMIP7 PFT raw datasets for SSPs, so default to CMIP6 for these. For other compsets default to CMIP7. User may modify to a non-default value in env_run.xml.
Caveats:
1) We supply only CMIP7 C13/C14 isotope datasets, so these get used regardless.
2) We supply only CMIP7 population density with ctsm6 in non-SSP cases, because the fire model is calibrated to that; conversely, for pre-ctsm6 and for SSP we supply only CMIP6 population density.
3) We supply only CMIP6 nitrogen deposition (ndep), so this gets used regardless.
4) For DATM we supply only CMIP6 aerosols.
5) For DATM we supply only CMIP6 CO2

If CTSM will set the dust settings in drv_flds_in (TRUE), or if ATM (i.e. CAM) will - DO NOT EDIT (set by compset name)

Sets CLM default namelist options related to model configuration.
    clm: Configuration used for climate applications (CLM)
    nwp: Configuration used for numerical weather prediction applications
    

Sets CLM default namelist options related to model structure.
    standard: Standard model structure, allowing for more subgrid heterogeneity,
    deeper soil, etc., at the cost of slower speeds.
    fast: Simplified model structure, achieving faster speeds at the cost of less
    subgrid heterogeneity, shallower soil, etc.
    

CLM namelist use_case.
      Determines the use-case that will be sent to the CLM build-namelist utility.
      This is normally set by the component set. This is an advanced flag and should only be
      used by expert users.

CLM build-namelist options

Determines how CLM will determine where CO2 is set.
      If value is constant, it will be set to CCSM_CO2_PPMV,
      if value is either diagnostic or prognostic, the atmosphere model
      MUST send it to CLM. CLM_CO2_TYPE is normally set by the specific
      compset, since it HAS to be coordinated with settings for the
      atmospheric model. Do not modify this variable. If you want to modify for
      your experiment, use your own user-defined component set
      This is an advanced flag and should only be used by expert users.

CLM-specific namelist settings for -namelist option in the CLM
      build-namelist. CLM_NAMELIST_OPTS is normally set as a compset variable
      and in general should not be modified for supported compsets.
      It is recommended that if you want to modify this value for your experiment,
      you should use your own user-defined component sets via using create_newcase
      with a compset_file argument.
      This is an advanced flag and should only be used by expert users.

Determines whether Nitrogen Deposition fluxes will come from the ATM model via the CESM Coupler
    or if a dataset will be read in by CTSM. Nitrogen Deposition is only needed for BGC cases.
    

Turn on any settings for accellerating the model spinup. SASU is to run the Semi-Analytic Spin-Up with the CN soil matrix method.
    

Resolution name for user-created resolutions. This is especially used
      for single point and regional resolutions created via subset_data from
      the global datasets. This should be set when you use CLM_USRDAT as the grid
      to create_newcase.  The default value is UNSET.
      For NEON cases, this can be set to either NEON or NEON.PRISM, the latter of which would
      use PRISM precipitation instead of the default NEON precipitation. NEON cases then also
      use the variable NEONSITE to specify the exact site. PLUMBER cases use the variable 
      PLUMBER2SITE to specify the exact site.

Directory name for user-created surface, landuse, and datm datasets.
      This is used as an argument in user_mods namelists (e.g. user_nl_clm,
      user_nl_datm_streams) generated with the subset_data script. Users
      should modify this variable (in shell_commands or elsewhere) to set the
      location of user-created data. The default value is UNSET.

Flag to the CLM build-namelist command to force CLM to do a
      cold start (finidat will be set to blanks).
      A value of on forces the model to spin up from a cold-start
      (arbitrary initial conditions). Setting this value in the xml file will take
      precedence over any settings for finidat in the $CASEROOT/user_nl_clm file.

User mods to apply to specific compset matches. 

Name of site for NEON tower data

Version id of Neon data

Name of site for PLUMBER tower data