Restart files contain all of the initial condition information
necessary to restart from a previous simulation. These files are in a
standard IEEE 64 bit binary format. A restart file is not necessary for
an initial run, but is highly recommended. The initial conditions
that are internal to the ice model produce an unrealistic ice cover
that an uncoupled ice model will correct in several years. The initial
conditions from a restart file are created from an equilibrium solution,
and provide more realistic information that is necessary if coupling
to an active ocean model. The frequency at which restart files are created
is controlled by the namelist parameter dumpfreq.
The names of these files are proceeded by the namelist parameter
dump_file and, by default are written out yearly to the /rest
directory under the executable directory. To change the directory where these files are
located, modify the variable $RSTDIR at the top of the setup script.
The names of the restart files follow the CCSM Output Filename Requirements.
The form of the restart file names are as follows:
For example, the file $CASE.csim.r.0002-01-01-00000 would be written out at the end of year 1, month 12. A file containing the name of a restart file is called a restart pointer file. This filename information allows the model simulation to continue from the correct point in time, and hence the correct restart file.
A pointer file is an ascii file named rpointer.ice that contains the path and filename of the latest restart file. The model uses this information to find a restart file from which initialization data is read. The pointer files are written to and then read from the executable directory. For startup runs, a pointer is created by the ice setup script Whenever a restart file is written, the existing restart pointer file is overwritten. The namelist variable pointer_file contains the name of the pointer file. Pointer files seldom need editing. The contents are usually maintained by the setup script and the component model.