Any tips on setting surface precipitation at each time step in CLM

[ultrasty]

Hi everyone,
I am going to carry out an experiment setting surface precipitation as prescribed values at global domain. I am currently using CESM 2.1.3 and relatively new to modifying CLM. Are there any documents or tips on modifying CLM? Thanks in advance.
Best,
Andrew

 

[oleson]

Modifying precipitation and other atmospheric forcing input to CLM is through the data atmosphere model (datm) as described here:

6. Data Atmosphere (DATM) — CIME cime5.6 documentation

You could create new datm forcing files and then specify them to be read in by following:

7. Customizing your input variables — CIME cime5.6 documentation

Alternatively, you could change the incoming precipitation within the code, if your precipitation modification was simple. The code for cesm2.1.3 (although the supported release version is release-cesm2.1.5) is here:

cime/src/components/data_comps/datm/datm_comp_mod.F90

The datm mode for driving CLM is CLMNCEP.