Questions on restarting from AD spinup, rpointer files, and MOSART in CTSM (5.3.075)

[pengzhou]

Dear CESM scientists,

Hello! I have a few questions about my simulations, many thanks in advance for your help.

I’m running the latest CTSM and have completed the AD (accelerated decomposition) spinup with compset I2000Clm60Bgc and resolution f19_g16. I’m now preparing to start the regular (non-AD) run. In user_nl_clm, I plan to set: finidat = "/.../....clm2.r....", Do I also need to set or provide corresponding cpl.r and datm.r files for this regular run?

I’ve noticed that in the new CTSM, the AD spinup no longer produces rpointer.drv; instead I see rpointer.cpl.*, rpointer.lnd.*, and rpointer.atm.*. Should all three rpointer files be copied into the new case as well?

For a study focused on GPP using prescribed atmosphere (DATM) with I2000Clm60Bgc, is it acceptable to turn off MOSART (MOSART_MODE=NULL)? If I simulate crops, should MOSART also be turned off?

Finally, after completing the spin-up, do I need to run the transient simulation multiple times to reach equilibrium, or is a single run sufficient?

Thank you very much for your guidance!
Best regards,
Peng

 

[oleson]

No, just the finidat will work fine.
You can turn off MOSART if you aren't interested in river discharge into the ocean. It doesn't feed back into any other components in an I-case.
A single transient run is sufficient in an I-case.

 

[pengzhou]

No, just the finidat will work fine.
You can turn off MOSART if you aren't interested in river discharge into the ocean. It doesn't feed back into any other components in an I-case.
A single transient run is sufficient in an I-case.

Thank you very much for your quick and helpful reply—it was extremely useful!
I have two brief follow-up questions:

1. In the new CTSM, the AD spinup no longer produces rpointer.drv, but instead I see rpointer.cpl.*, rpointer.lnd.*, and rpointer.atm.*. When starting the regular (non-AD) run from the AD state, do I need to copy all three of these rpointer files into the new case?
2. My AD spinup has run for 390 years. Before beginning the transient simulation, how many years of regular (non-AD) spinup would you recommend (e.g., 650 years, or shorter/longer)? My study focuses on GPP in an I-case using prescribed atmosphere (DATM).

Many thanks again for your guidance!
Best regards,
Peng

 

[oleson]

1. If you are just specifying finidat in a startup post-AD run, then you wouldn't need to copy the rpointer files.
2. GPP should come into equiiibrium pretty quickly (< 50 years). SOM will take much longer. You can use the spinup scripts in tools/contrib to plot the different variables and judge whether the simulation is spunup. See also: 1.5.5. Spinup of CLM5.0-BGC-Crop — ctsm release-clm5.0 documentation for spinup information.

 

[pengzhou]

1. If you are just specifying finidat in a startup post-AD run, then you wouldn't need to copy the rpointer files.
2. GPP should come into equiiibrium pretty quickly (< 50 years). SOM will take much longer. You can use the spinup scripts in tools/contrib to plot the different variables and judge whether the simulation is spunup. See also: 1.5.5. Spinup of CLM5.0-BGC-Crop — ctsm release-clm5.0 documentation for spinup information.

Many thanks again for your prompt and helpful reply—it’s been extremely valuable.
I wanted to double-check one point because I had previously followed the CLM5.0 spinup example in the documentation (Section 1.5.5.2), where the last CLM restart file (e.g., BGC_spinup.clm2.r.0201-01-01-00000.nc) is copied and the files rpointer.atm and rpointer.drv are also copied into the new case directory. In my current CTSM runs, after completing the AD spinup I don’t see rpointer.drv; instead I only have rpointer.cpl.*, rpointer.lnd.*, and rpointer.atm.*.
Just to confirm based on your guidance: when starting the regular (non-AD) run in startup mode after AD, is it sufficient to specify finidat in user_nl_clm and not copy any rpointer.* files into the new case directory?
Thank you again for your guidance!
Best regards

 

[oleson]

For RUN_TYPE = startup, you don't need to copy the rpointer files into the run directory (there won't be a problem if you do so though), they won't be used. The instructions should be clarified, sorry for the confusion.

 

[pengzhou]

For RUN_TYPE = startup, you don't need to copy the rpointer files into the run directory (there won't be a problem if you do so though), they won't be used. The instructions should be clarified, sorry for the confusion.

Thank you very much for your clarification. Wishing you a happy life~