Creating New Restart Files

Sometimes when starting a new model, suitable restart files for the chosen time period cannot be found. There are two ways to make restart files.

Restart Files the Quick Way

The quickest way to get a restart file is to find one for the same model type, grid size, and month (i.e. GEOS-5, 4x5, July). Let's say that you need a restart file for July 1, 2001, but you can only find one for July 1, 2003. To get a good restart file for your simulation, follow these steps:
  1. Rename the restart file from 'restart.2003070100' to 'restart.2000070100'
  2. Set up a spinup run from July 1, 2000 to July 1, 2001 and make sure the 'save restarts' option is set to T
  3. Run the spinup simulation
  4. When complete, the newly-created restart file called 'restart.2001070100' can be used for your desired simulation

Restart Files the Slightly Longer Way

When no suitable restart files are available, it is possible to create one from scratch using the MAKE_RESTART routine. One example of of an IDL program might be:
tracerlist = indgen(43)+1 ; creates an array with values from 1 to 43

	 OUTRESOLUTION=2,                       $
	 OUTFILENAME='restart.2x25.2005010100', $
	 TAU0=NYMD2TAU( 20050101L ),            $
	 DATAVALUE=0.001,                       $
	 TRACERLIST=tracerlist,                 $
	 UNIT='ppbv',                           $
This will create a restart file named 'restart.2x25.2005010100' with all concentration values set at 0.001 ppbv. At this point, the spinup process is the same as described above, except the period of the spinup run should be increased to at least two years since it will take longer for the values to converge on their stable values.