eagles-project/mam4xx

EAMxx aerosol optics stub process

Closed this issue · 6 comments

jeff-cohere commented

Now that we have mam4xx running in EAMxx, we can focus on some outstanding issues. It turns out that the RRTMGP radiation process expects certain fields that contain optical parameters describing how aerosols affect incoming and outgoing solar radiation.

We need an aerosol optics atmosphere process for EAMxx anyway, so we might as well set up a stub for it and have it populate the required fields with "representative" values. The fields are:

  • aero_g_sw: aerosol short-wavelength asymmetry parameter [-]
  • aero_ssa_sw: aerosol short-wavelength single-scattering albedo [-] (typically between 0.7 and 1)
  • aero_tau_sw: aerosol short-wavelength optical depth/thickness (AOD) [-] (0 at top of atmosphere, positive below)
  • aero_tau_lw: aerosol long-wavelength optical depth/thickness (AOD) [-] (0 at bottom of atmosphere, positive above?)

This issue tracks the task of setting up a simple stub aerosol optics atmosphere process similar to our existing aerosol microphysics process. The code will live in EAMxx and just populate the above fields with reasonable values.

For those interested, the code is here and here.

@singhbalwinder @pressel

Other things to include in the associated EAMxx PR

  • Reenable standalone HOMME-MAM4 test (since it might work when radiation fields are present)
  • Normalize file/class/instance names for the MAM4 microphysics. Choose exactly one of:
    • MAMMicrophysics
    • MAM4Microphysics <-- my favorite

Then the process can be referred to by mam4microphysics in an input file.

jeff-cohere commented

Looks like the stub process is doing its job and providing the aerosol optics to RRTMGP--I'm now able to run an ne4 simulation to completion.

mahf708 commented

@jeff-cohere I am very interested in this specific topic (radiation/optics). I am working on the EAM side on some extracurricular improvements. I am commenting here to register my interest 😺

jeff-cohere commented

Thanks @mahf708 . This issue tracks our last "plumbing" PR in our EAMxx integration task before we get to physics, so there's no physics here. But when we have ported MAM4's optics logic, we'll use it to replace the fake stuff we refer to here.

jeff-cohere commented

Here's the EAMxx PR for this task: E3SM-Project/scream#2450

jeff-cohere commented

The EAMxx PR finally got merged, so I'm closing this issue.

  • 🎉1
mahf708 commented

Excited to see what comes up next 🥳