CESM3-CAM7 config

[elisabm]

I am trying to set up a first test simulation using cesm3_0_beta06 with CAM7-Chemistry enabled. At this stage I have not modified the code yet, but the longer-term goal is to implement the intermediate-complexity iron chemistry mechanisms (MIMI: Improved methodologies for Earth system modelling of atmospheric soluble iron and observation comparisons using the Mechanism of Intermediate complexity for Modelling Iron (MIMI v1.0)) into CESM3-CAM7.

I had a look here to check which specific configurations I could use: https://ncar.github.io/CAM/doc/build/html/users_guide/atmospheric-configurations.html
However, I am unsure which CESM3-CAM7 compset is recommended for initial testing. Maybe?:

F2000dev : 2000_CAM70_CLM60%SP_CICE%PRES_DOCN%DOM_MOSART_SGLC_SWAV

Additionally, could you advise which grids are compatible with this configuration? Is it possible to run a CONUS grid setup with CAM7-Chem in cesm3_0_beta06, or is that not yet supported?

Thank you for your help

 

[Danny Leung]

Hi Elisa!
Good to know that you are implementing MIMI into CESM3.
I first wonder if you need complex chemistry for MIMI. I suspect you want reasonable levels of acids in your model for calculating soluble iron concentrations.
Compsets like F2000climo, FHIST (minimal chemistry), and FCHIST (complex chemistry) will be for CAM6 physics.
For CESM3/CAM7 physics, FHISTC_LTt1s (complex chemistry) or FHISTC_LTt4s (intermediate-level chemistry) might be what you want. If you want minimal chemistry, then FHISTC_LTso is the choice. Note that CAM6 and CAM7 have very different aerosols and chemistry. CAM6 and CAM7 use different dust emission schemes by default, and SOA levels can change from. I don't think fires change that much.
These compsets have inactive ocean, which might be what you want at the moment. I wonder if you might want an active ocean for biogeochemistry in the future, and in that case these compsets can't be used.
Hope this helps,
Danny

 

[Danny Leung]

My overall recommendation is FHISTC_LTt1s for CAM7 physics. It is more expensive, and we still have biases in some acids (e.g., HNO3), but it contains the best chemistry and oxidant levels in CESM in the moment.
Danny

 

[elisabm]

Thanks a lot, Danny. This is very helpful.
I think I will start porting with the minimal chemistry FHISTC_LTso, since MIMI does not currently need full chemistry. However, in the near future, we may consider moving to FHISTC_LTt1s or FHISTC_LTt4s.