Can I change the namelist when running a case?

[Biyin]

Dear All,

I am running a case with CESM2.2, FCHIST. It has been running for several days but recently encountered an error and stopped.

Now I want to change the stream year in docn_in
streams = "docn.streams.txt.prescribed 1850 1850 2016"

and change the stream year in ice_in
stream_year_first = 1850
stream_year_last = 2016

My question is: can I simply change these parameters in the namelist and continue the run, or do I need to modify the namelist and perform a branch run?

Best

 

[slevis]

I suggest trying with "continue" first and checking that your changes take effect. If they do not take effect or the run aborts, try again with a "branch" run. Again, if the changes do not take effect or the run aborts, then do a "hybrid" run, which is very similar to "branch" but more flexible.

When you determine the right approach (continue, branch, or hybrid), please post an update here for future reference. Thank you :-)

 

[Biyin]

I changed the "SSTICE_YEAR_START" and "SSTICE_YEAR_END" in env_run.xml and continue the run

 

[erik]

I just want to caution that not all namelist parameters can be changed while a simulation is running. In some cases it will still run, but not really use the new settings, it will actually be using the original settings from restart files. So I recommend looking in the log files to make sure the settings did actually get used. Since, as I say it depends on the specific setting, the approach that makes the most sense is to check and make sure you got the behavior you intended. Doing a branch simulation is the safe way to ensure you will get the intended behavior.