b.e21.BHIST.f09_g17.CMIP6-historical.001 initial conditions

[zhangguangzhi]

Dear CESM community,

I am trying to understand how the land initial conditions were configured in the CESM2 CMIP6 historical simulation b.e21.BHIST.f09_g17.CMIP6-historical.001.

When I checked the user_nl_clm file available here:

https://svn-cesm2-expdb.cgd.ucar.edu/public/b.e21.BHIST.f09_g17.CMIP6-historical.001/user_nl_clm

I noticed that there is no explicit specification of a finidat file.

I would like to confirm how the CLM initial state was provided in this case. My understanding is that historical simulations are typically branched from a piControl run, and therefore the CLM initial condition should come from the piControl restart files rather than a finidat file specified in user_nl_clm.

I am planning to run historical and SSP experiments and would like to follow the same approach—using the piControl restart as the initial condition for CLM. Could you please clarify:

1. Was the CLM initial condition in this CMIP6 historical case taken directly from a piControl restart via a branch run?
2. If so, which piControl case and restart date were used?
3. Is there a recommended way to obtain or reproduce the same initial restart files for historical branching?

In addition, I would like to reproduce the configuration as strictly as possible. Is there any way to access the original case run directory or archive for b.e21.BHIST.f09_g17.CMIP6-historical.001, or any documentation that records the full case settings (XML files, namelists, and scripts)? This would help ensure that parameter settings are consistent with the original experiment.

Thank you very much for your help.