Update 1850 aerosol and ndep datasets for CAM

[ekluzek]

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

@tilmes did a simulation and created datasets that can be used from it. This is something we will have to do at least once during the spinup procedure. This is also something that needs to be coordinated with the offline models as part of the spinup, so we are pointing to the same datasets at the appropriate steps.

Since, we know answers will change it seems prudent to me to use the preliminary dataset that's going to be closer to the final version -- rather than using the old CMIP6 forcing.

The preliminary datasets that are available now are here:

/glade/derecho/scratch/tilmes/archive/b.e30_alpha07c_cesm.B1850C_MTt4s.ne30_t232_wgx3.251.001/atm/proc

A simulation where the datasets are used is documented here:

NCAR/cesm_dev#264

The simulation where the datasets were created is documented here:

NCAR/cesm_dev#216

Ozone could also be updated, it's just not critical for the offline models for the coupled model spinup. CTSM is the only offline model that uses Ozone, and it's only used for experimental configurations and not the standard simulations.

The issues that document this for CDEPS for the offline models are here:

ndep:
ESCOMP/CDEPS#388
aerosols:
ESCOMP/CDEPS#389
ozone:
ESCOMP/CDEPS#390

The spinup procedure is documented here and each step with a B1850C_MTt4s simulation will need the dataset extracted afterwards and then put into both CAM and CDEPS

https://docs.google.com/presentation/d/1Z-SOtJHVU-hRcPRDXNpbl4vmh4-ZGMTulLJ8BSscf18/edit?slide=id.g3bd7fecfd64_0_0#slide=id.g3bd7fecfd64_0_0

It only explicitly says we need chemistry output at step 2. But, it could also be done at step 5.

So it doesn't HAVE to happen now with the preliminary dataset. But, we do HAVE to have all models coordinated after step 2 is done, so they are using the same datasets at step 3 and later. And as I say above it seems prudent to get the preliminary one in earlier so that the jump to the final one isn't as big.

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

@tilmes @cecilehannay @fvitt

Will this change (regression test) answers?

Yes

Will you be implementing this enhancement yourself?

No

[ekluzek]

There's some talk about where the data for this should go. For CMIP6 we put the aerosols under $DIN_LOC_ROOT/atm/cam/chem/trop_mozart_aero/aero/aero, ndep under: $DIN_LOC_ROOT/lnd/clm2/ndepdata, ozone under: $DIN_LOC_ROOT/cdeps/datm/ozone.
(Note: I don't know why "aero" is repeated three times in the above directory structure).

For the CMIP7 data I'm proposing it go under something like:

$DIN_LOC_ROOT/atm/cam/chem/trop_strat_mam5_ts4_aero

with maybe three subdirectories at that point: aero, ozone, and ndep?

We need to coordinate the location of the data for CDEPS to be used by surface models, so we want something that makes sense for everyone.

[briandobbins]

A few of the scientists recommend a separate directory (maybe something like 'chem/spinup/trop_strat_mam5_ts4_aero', or 'chem/trop_strat_mam5_ts4_aero_spinup', so that these temporary files are not confused with the later, finalized files, as we know they will change.

This has been a challenge in the past, since folks look through the directories and can grab files. I'll add this to the email thread, too.

[cacraigucar]

I like the name chem/trop_strat_mam5_ts4_aero_spinup. I will use this unless I hear differently (and I am setting up my runs now and will start things in a hour or so)

[cacraigucar]

The aerosol files are already in cam6_4_156. BUT, they are not in a spinup directory. Do folks want me to move them to a spinup directory or not? If I don't hear anything back, I will leave them where they are.

[cacraigucar]

After discussion with @PeterHjortLauritzen, we have decided to leave the files in the locations which were specified in cam6_4_156.