1.1.9. Scientific Validation

In this section we go over what has been extensively tested and scientifically validated with CLM5.0, and maybe more importantly what has NOT been tested and may NOT be scientifically validated. You can use all features of CLM, but need to realize that some things haven’t been tested extensively or validated scientifically. When you use these features you may run into trouble doing so, and will need to do your own work to make sure the science is reasonable.

1.1.9.1. Standard Configuration and Namelist Options that are Validated

See http://www.cesm.ucar.edu/models/cesm1.2/clm/CLM_configurations_CESM1.2.pdf for an explanation of what configurations are scientifically validated for CLM5.0. For CLM4.0 changes to the science of the model are minimal since CESM1.1.1 so we expect answers to be very similar to using it.

In the sections below we go through configuration and/or namelist options or modes that the user should be especially wary of using. You are of course free to use these options, and you may find that they work functionally. Although in some cases you will find issues even with functionality of using them. If so you will need to test, debug and find solutions for these issues on your own. But in every case you will need to go through more extensive work to validate these options from a scientific standpoint. Some of these options are only for CLM5.0 while others are for both CLM4.0 AND CLM5.0 we explicitly say which they apply to.

1.1.9.2. Configurations that should be used with caution

There are some options in CLM5.0 that are available but either not tested extensively, or not scientifically evaluated. These options should be used with caution. And any options that deviate from the scientifically supported configurations can have issues. The IMPORTANT_NODES file goes into more details on this.

The IMPORTANT_NOTES (which can be found in $CTSMROOT/doc) is repeated here.

$CTSMROOT/doc/IMPORTANT_NOTES                                   Jun/08/2018
                                                                Erik Kluzek

I.) For clm4_0:

Configure Modes NOT scientifically validated, documented, supported or even advised to be used:
(options to CLM_CONFIG_OPTS)

   SNICAR_FRC   (-snicar_frc)
       This mode is tested and functional, but is NOT constantly scientifcally validated, and should be 
       considered experimental.

Namelist items that should NOT be exercised:

  glc_dyntopo            Change topographic height over glacier MEC (Not functional)
  suplnitro='ALL'        (suplnitro='ALL' with -bgc cn)
                         The suplemental Nitrogen mode of the CN model is known 
                         to be too productive.
  urban_traffic:         Not currently functional

II.) For clm4_5/clm5_0:

Namelist items that are not regularly tested or used. Some aren't even implemented.

    See

    ../bld/namelist_files/namelist_definition_clm4_5.xml -- for definitions

    CN_evergreen_phenology_opt
    CN_partition_opt
    CN_residual_opt
    CNratio_floating
    all_active
    allowlakeprod
    anoxia_wtsat
    carbon_resp_opt
    ch4offline
    downreg_opt
    fin_use_fsat
    lake_decomp_fact
    no_frozen_nitrif_denitrif
    nscalar_opt
    perchroot
    perchroot_alt
    plant_ndemand_opt
    reduce_dayl_factor
    replenishlakec
    substrate_term_opt
    temp_scalar_opt
    urban_traffic
    use_extralakelayers
    use_lai_streams
    use_snicar_frc
    use_vichydro
    usefrootc
    vcmax_opt = 4

    FATES namelist options: FATES is a new experiemental subcomponent where all of it's options are
                            under current development. As such FATES and all of it's options should
                            be considered experimental.

   use_fates
   use_fates_spitfire
   use_fates_logging
   use_fates_planthydro
   use_fates_ed_st3
   use_fates_ed_prescribed_phys
   use_fates_inventory_init
   fates_inventory_ctrl_filename