4.8 Example Namelists

This section shows several examples of namelists from the coupled and uncoupled ice models. These examples are taken directly from csim.buildnml_prestage.csh for the coupled model and from csim.setup.csh for the uncoupled model. Most of the variables in the namelist are determined from environment variables set elsewhere in the scripts. Since the namelists from the coupled model are "resolved" by the scripts, meaning that the values of most of the shell script variables are put directly into the namelist, examples are shown for the most commonly used configurations. Variables that are commonly changed directly in the namelist are the timestep dt and the number of subcycles per timestep in the ice dynamics ndte.

4.8.1 Example 1: CCSM Fully Coupled

The following example is the namelist used for CCSM fully coupled, or the B configuration. The variables that are still set to shell script variables have been set at the top of csim.buildnml_prestage.csh or in other scripts. A completely resolved version of the namelist will be written to ice_in in the executable directory.

cat << EOF >! ice_in
  &ice_nml
    runid         = 'TER.01a.T85_gx1v3.B.bluesky.105608'
  , runtype       = '$runtype'
  , istep0        = 0
  , dt            = 3600.0
  , ndte          = 120
  , ndyn_dt       = 1
  , npt           = 99999
  , diagfreq      = 24
  , histfreq      = 'm'
  , dumpfreq      = 'y'
  , dumpfreq_n    = 1
  , hist_avg      = .true.
  , restart       = $restart
  , print_points  = .false.
  , kitd          = 1
  , kdyn          = 1
  , kstrength     = 1
  , evp_damping   = .false.
  , snow_into_ocn = .true.
  , advection     = 'remap'
  , grid_type     = 'displaced_pole'
  , grid_file     = 'data.domain.grid'
  , kmt_file      = 'data.domain.kmt'
  , incond_dir    = '$runinidir/'
  , incond_file   = '$CASE.csim.i.'
  , restart_dir   = '$runrstdir/'
  , dump_file     = '$CASE.csim.r.'
  , history_dir   = '$runhstdir/'
  , history_file  = '$CASE.csim.h'
  , albicev       = 0.73
  , albicei       = 0.33
  , albsnowv      = 0.96
  , albsnowi      = 0.68
  , no_ice_ic     = $no_ice_ic
  , oceanmixed_ice             = .false.
  , oceanmixed_ice_file        = 'oceanmixed_ice.nc'
  , oceanmixed_ice_sst_init    = .false.
  , prntdiag_oceanmixed        = .false.
  , pointer_file  = 'rpointer.ice'
/

4.8.2 Example 2: Coupled Ice Only Model

This example is the M configuration. It is CSIM with the latm data atmosphere model, data land model, and the ocean mixed layer model within the ice model all communicating through the coupler. The following modifications will be made to the namelist when the resolved scrips are created for the M configuration. See the CCSM3 User's Guide on how to create scripts for the M configuration.

    runid         = 'TER.01a.T62_gx1v3.M.bluesky.095234'
  , oceanmixed_ice             = .true.
  , oceanmixed_ice_sst_init    = $oml_ice_sst_init

4.8.3 Example 3: Uncoupled Ice Model

This example is the namelist from the uncoupled ice model that resides in the file csim.setup.csh. npt has been modified, since it determines the length of the uncoupled run. The snow and ice albedos used by CCSM are not set in the name list. The default values set in ice_init.F are used.

cat << EOF >! ice_in
  &ice_nml
    runid        = '$CASE $CASESTR'
  , runtype      = '$RUNTYPE'
  , istep0       = 0
  , dt           = 3600.0
  , ndyn_dt      = 1
  , ndte         = 120
  , npt          = 240
  , diagfreq     = 24
  , histfreq     = 'm'
  , dumpfreq     = 'd'
  , dumpfreq_n   = 5
  , hist_avg     = .true.
  , restart      = $RESTART
  , print_points = .false.
  , kitd         = 1
  , kdyn         = 1
  , kstrength    = 1
  , evp_damping  = .false.
  , snow_into_ocn = .true.
  , advection    = 'remap'
  , grid_type    = 'displaced_pole'
  , grid_file    = 'data.domain.grid'
  , kmt_file     = 'data.domain.kmt'
  , incond_dir   = '$INIDIR/'
  , incond_file  = '$CASE.csim.i.'
  , restart_dir  = '$RSTDIR/'
  , dump_file    = '$CASE.csim.r.'
  , history_dir  = '$HSTDIR/'
  , history_file = '$CASE.csim.h'
  , pointer_file  = '$CSIMDIR/rpointer.ice'
  , oceanmixed_ice             = $OCEANMIXED_ICE
  , oceanmixed_ice_file        = 'oceanmixed_ice.nc'
  , oceanmixed_ice_sst_init    = $OML_ICE_SST_INIT
  , prntdiag_oceanmixed        = .false.
/

4.8.4 Example 4: Uncoupled Ice Model with Atmospheric Forcing

To run the uncoupled ice model with atmospheric forcing, the following options should be added to the above namelist:

  , ycycle       = 1
  , year_init    = 1997
  , fyear_init   = 1997
  , atm_data_dir = '/ptmp/$LOGNAME/csim_forcing/atm/gx3v5/'

4.8.5 Example 5: History File Namelist

The second namelist controls what variables are written to the history file. By default, all files are written to the history file. Variables that are not output are set in the namelist icefields_nml. Some of the following fields are not written to the history file since they can be retrieved from the ocean history files. The melt and freeze onset fields are not used, since the information they contain may not be correct if the model is restarted mid-year. The ice areas and volumes for categories six through ten are not used, since the default thickness distribution consists of five ice categories.

  &icefields_nml
    f_sst       = .false.
  , f_sss       = .false.
  , f_uocn      = .false.
  , f_vocn      = .false.
  , f_frzmlt    = .false.
  , f_strtltx   = .false.
  , f_strtlty   = .false.
  , f_mlt_onset = .false.
  , f_frz_onset = .false.
  , f_aice6     = .false.
  , f_aice7     = .false.
  , f_aice8     = .false.
  , f_aice9     = .false.
  , f_aice10    = .false.
  , f_vice1     = .false.
  , f_vice2     = .false.
  , f_vice3     = .false.
  , f_vice4     = .false.
  , f_vice5     = .false.
  , f_vice6     = .false.
  , f_vice7     = .false.
  , f_vice8     = .false.
  , f_vice9     = .false.
  , f_vice10    = .false.
  /