Introduce QPC7 and possibly QPS7 aquaplanet compsets

[cacraigucar]

What is the feature/what would you like to discuss?

Introduce CAM7 aquaplanet compsets. This may need to be LT and maybe MT.

QPS7 may be broken and if so, will be included at a later date

This PR depends on #813

Is there anyone in particular you want to be part of this conversation?

@brianpm

Will this change (regression test) answers?

Yes

Will you be implementing this enhancement yourself?

Any CAM SE can do this

[nusbaume]

I think (?) you meant to include @brianpm

[cacraigucar]

Good catch. I thought I hit the dropdown selection, but obviously I missed!

[brianpm]

I think QPC7 (prescribed SST with CAM7 physics) should work as expected.

QSC7, the slab-ocean version, may not work. I can't remember the exact issue, but I have had complaints that QSC6 does not work with the SE dynamical core.

For both QPC7 and QSC7, I'd recommend updating the use case to have seasalt_emis_scale = 0.0

As discussed by Me (2020, DOI: 10.1029/2019MS001874), having diagnostics sea salt emissions leads to a big TOA radiative signal that I don't think aquaplanets need.

[brianpm]

I have tested a prototype "QPC7" and it seems like things are working in the current cam-dev with the L58 configuration. My case directory is here: /glade/work/brianpm/my_cases/test_cases/eaton_rrtmg_qpc6_01

This is a very minor change compared to the out-of-the-box QPC6. Here's what I did:

• ./create_newcase --compset QPC6 --res ne30pg3_ne30pg3_mg17 ...
• ./xmlchange CAM_CONFIG_OPTS=-phys cam_dev -nlev 58 -model_top lt -aquaplanet -analytic_ic
• Set user_nl_cam:
  • seasalt_emis_scale = 0.0
  • analytic_ic_type = 'us_standard_atmosphere'

This produces a simulation that, as far as I can tell so far, is what we will want for QPC7. To that end, we can take this file as the new initial conditions file for QPC7: /glade/derecho/scratch/brianpm/archive/eaton_rrtmg_qpc6_01/atm/hist/eaton_rrtmg_qpc6_01.cam.i.0004-01-01-00000.nc

If major changes happen before the code freeze, we should just do another run to generate a new initial conditions file.

Still To Do : I still need to do the same thing for L93, but haven't had a chance.

Also Still To Do : These are using RRTMG and not RRTMGP, so maybe I will re-run once a tag with RRTMGP is produced (initial L58 attempt seems like something didn't work).