[ekluzek]

Description of changes

Add a script to handle creating aerosol monthly climatology from daily CPLHIST data.

The climatology script will be adapted in the future to work with historical and future scenarios, as well as doing an ensemble average over multiple CESM simulations. For historical, there were 5 year averages done, with a linear interpolation between those for each year. Adding the bit about ensemble average will be straight-forward, but perhaps a running average should be done, rather than fixed five year bins? I looked at the existing code that @olyson and @tilmes had, both of which were NCL, so need to be replaced and neither quite did what was needed. Since, this will be adapted in the future using LDF climatology isn't quite right either.

Specific notes

Contributors other than yourself, if any:

• @olyson @tilmes Claude

CTSM issues resolved or otherwise addressed, if any:

• (Replace this text, including GitHub issue #, and add more list items as needed)

If answers are expected to change, describe (delete this line otherwise): No

Any user interface changes (namelist or namelist defaults changes)? No

Testing planned or performed, if any:

• python testing

Requirements before merge:

• I have followed the CTSM contribution guidelines.

• The code in this PR branch builds with no errors.
• The code in this PR branch runs with no errors. Briefly describe tested configuration(s):
• This either (a) does not change answers, (b) it only changes answers at roundoff level, or (c) I have performed a scientific evaluation of the answer changes. Which?: a

• I have reviewed relevant parts of the CLM documentation Tech Note or User's Guide to determine if anything needs to be changed or added. If it does, describe:
• This PR either (a) does not create a need to update the documentation or (b) includes required documentation updates (see guidelines for contributing documentation). Which?: a

[slevis-lmwg]

Erik and I discussed this PR last Monday and today.
Erik posted a few comments to address.
Approving.

[ekluzek]

Things I'll do:

• Seperate into base class and aerosol specific script
• Add unit tests using Claude to help
• Remove the batch capability from the aerosol specific one

[ekluzek]

I'm going to split this into two, one for the specific things for aerosols, and then the more general base class stuff

[ekluzek]

The aerosol specific one doesn't really need the batch capability, so I'll remove it from it. But, the base class can keep it for other purposes.

[ekluzek]

The other thing I'll do is to add tests using Claude to help me with that.