Exercises#
Exercise: Initializing a simulation from a previous one
Create a case b1850_hybrid
using the B1850-tutorial
compset at f19_g17
resolution.
Set the run as an hybrid run from the run: b1850_initial
for 1st Jan for year 2.
The initial run is in: /scratch/data/b1850_initial/
Here you’ll make use of restart files from a previously run simulation, to initialize your simulation
using a hybrid initialization.
A 1 year simulation, called b1850_initial
, which uses the B1850-tutorial
compset at f19_g17
resolution
as already been performed and the archive directory is IN:
/scratch/data/b1850_initial/
Here you’ll find all the restart files for 1st Jan for year 2 of this run
/scratch/data/b1850_initial/rest/0002-01-01-00000
Click here for hints
Create a new case, using the B1850-tutorial
compset at f19_g17
resolution. Call it b1850_hybrid
and put it in ∼/cases
.
Set up the case.
The following changes to xml parameters in env run.xml need to be performed to run the hybrid initialization.
#change to a hybrid initialization
./xmlchange RUN_TYPE=hybrid
# set the name of the run from which you are initializing
./xmlchange RUN_REFCASE=b1850_initial
# set the path to the initialization files that you want to use
./xmlchange RUN_REFDIR=/scratch/data/b1850_initial/rest/0002-01-01-00000
# sets the date of initialization - corresponds to the date of the initialization files being used
./xmlchange RUN_REFDATE=0002-01-01
# ensures it automatically obtains the restarts and initial conditions from RUN_REFDIR specified below
./xmlchange GET_REFCASE=TRUE
Lets also output some high frequency fields so we can see the history fields in a short 5 day run. Add the following to user nl cam to output daily precipitation
fincl2='PRECT'
nhtfrq=0,-24
mfilt=1,1
Build the case. Submit it.
Is it running? Are the history files being created?
Note that the default is RUN_STARTDATE=0001-01-01
. This means that even though you have
initialized from January 1st year 2, the dates of your run will start from January 1st year 1. In a
hybrid run, you can change RUN_STARTDATE
to any date you like
Click here for the solution
create a new case
go into scripts directory into the CESM code and run the create_newcase
command
cd $CESMROOT/cime/scripts
./create_newcase --case ~/cases/b1850_hybrid --compset B1850-tutorial --res f19_g17
case setup
go in case directory and run case_setup
cd ~/cases/b1850_hybrid
./case.setup
Set a hybrid run and point to the reference case
./xmlchange RUN_TYPE=hybrid
./xmlchange RUN_REFCASE=b1850_initial
./xmlchange RUN_REFDATE=0002-01-01
./xmlchange RUN_STARTDATE=0001-01-01
./xmlchange RUN_REFDIR=/scratch/data/b1850_initial/rest/0002-01-01-00000/
./xmlchange GET_REFCASE=TRUE
namelist modifications
Add to user_nl_cam
fincl2='PRECT'
nhtfrq=0,-24
mfilt=1,1
Build and submit
qcmd -- ./case.build
./case.submit