using CAM output from a previous run to run a CLM case

[pgoddard]

Hello, I'm looking for guidance on how to use CAM output from a previous run to serve as initial and boundary conditions to run a CLM case (I think this is referred to as a land model run with a data driven atmosphere). Can someone point me to a good place to begin as I work to better frame my question?

 

[oleson]

Generally, we use what we call coupler history mode in which coupler history files are saved from a coupled run and then used in "CPLHIST" datm mode to force CLM. A brief, somewhat dated, description is here:

1.5.10. Running with atmospheric forcing from a previous simulation — ctsm CTSM master documentation

If you already have your coupled run completed but haven't save any coupler history files, then you'd have to construct forcing files compatible with the datm.

 

[pgoddard]

Great, thanks. This should get me started.

 

[pgoddard]

Hi Keith,
From the documentation you linked, I have a question regarding where to find a file:
The instructions read to:
"cp ../../models/drv/driver/ccsm_comp_mod.F90 SourceMods/src.cpl" (where the ../.. takes one to the cime/ directory)
Where would I find the equivalent file "../../models/drv/driver/ccsm_comp_mod.F90" in my cime directory tree? Is the file ccsm_comp_mod.F90 called something different in later versions of CESM? I am using CESM2.2.2.

 

[pgoddard]

Hi Keith,
I believe I found the correct file in the cime directory tree
(local path to my_cesm)/cime/src/drivers/mct/main/cime_comp_mod.F90

Could you confirm this? What are the next steps/I'm not sure what I need to "edit the driver code in order to save the correct list of fields (see note below)"

Thank you for your time.

 

[oleson]

Sorry, if you using release-cesm2.2.2, then you shouldn't have to make any changes to the code.
You should just be able to set the following in your user_nl_cpl in your case directory (which I assume is either an F-case or a B-case) to generate the coupler history files:

histaux_l2x1yrg = .true.
histaux_a2x24hr = .true.
histaux_a2x3hr = .true.
histaux_a2x1hri= .true.
histaux_a2x1hr = .true.
histaux_r2x = .true.

I should note though that the coupler history files that are generated can only be used by CTSM tags near ctsm5.1.dev061 or earlier. After that tag, the driver changes from mct to nuopc and the coupler history file configuration also changes.

 

[pgoddard]

Hi Keith, thank you for your help. My PI and I are reviewing our methodology and this information is a great help. I'll post again if I have further questions.