The namelist variables that control the frequency of the model diagnostics, netCDF history, and restart files are shown in Table 1. By default, diagnostics are written out once every 48 timesteps to the ascii file ice.log.$LID (see section 9.1). $LID is a time stamp that is set in the main script.
The namelist variable histfreq controls the output frequency of the netCDF history files; writing monthly averages is the default. The content of the history files is described in section 9.3. The value of hist_avg determines if instantaneous or averaged variables are written at the frequency set by histfreq. If histfreq is set to '1' for instantaneous output, hist_avg is set to .false. within the source code to avoid conflicts. The latest version of CICE allows for multiple history streams, currently set to a maximum of 5. The namelist variables, histfreq and histfreq_n are now arrays which allow for different frequency history file sets. More detail on this is available in 9.3.
The namelist variable pointer_file is set to the name of the pointer file containing the restart file name that will be read when model execution begins. The pointer file resides in the scripts directory and is created initially by the ice setup script but is overwritten every time a new restart file is created. It will contain the name of the latest restart file. The default filename ice.restart_file shown in Table 1 will not work unless some modifications are made to the ice setup script and a file is created with this name and contains the name of a valid restart file; this variable must be set in the namelist. More information on restart pointer files can be found in section 9.2.
The variables dumpfreq and dumpfreq_n control the output frequency of the netCDF restart files; writing one restart file per year is the default and is set by the CESM driver. The default format for restart files is now netCDF, but this can be changed to binary through the namelist variable, restart_format.
If print_points is .true., diagnostic data is printed out for two grid points, one near the north pole and one near the Weddell Sea. The points are set via namelist variables latpnt and lonpnt. This option can be helpful for debugging.
incond_dir, restart_dir and history_dir are the directories where the initial condition file, the restart files and the history files will be written, respectively. These values are set at the top of the setup script and have been modified from the default values to meet the requirements of the CESM filenaming convention. This allows each type of output file to be written to a separate directory. If the default values are used, all of the output files will be written to the executable directory.
incond_file, dump_file and history_file are the root filenames for the initial condition file, the restart files and the history files, respectively. These strings have been determined by the requirements of the CESM filenaming convention, so the default values are set by the CESM driver. See 9.2 and 9.3 for an explanation of how the rest of the filename is created.