[QUESTION] AOD diagnostics in v13.0.0

[kbilsback]

Dear GC Team, I am using v13.0.0 and would like to output AOD tracers to compare to AERONET. I tried using the "AODHygWL1_" diagnostic in the AEROSOLS menu of HISTORY.rc; however, it appears that this is only the hygroscopic component of AOD. Is there a way for me to output the full AOD, not just the hygroscopic component? In the past, I had used the tracers 517-522 in the ND49 menu, but I haven't been able to find where these tracers ended up in the HISTORY.rc diagnostics and I don't see an option for using ND49 in v13.0.0. Thanks!

[yantosca]

Hi @kbilsback, thanks for writing. For the GEOS-Chem benchmarks, we use these diagnostics to create the total AOD plots and tables.

diag name,  plot name in PDF
AODDust: Column_AOD_Dust
AODHyg550nm_BCPI: Column_AOD_BCPI
AODHyg550nm_OCPI: Column_AOD_OCPI
AODHyg550nm_SALA: Column_AOD_SALA
AODHyg550nm_SALC: Column_AOD_SALC
AODHyg550nm_SO4: Column_AOD_SO4
AODPolarStratCloud550nm: Column_AOD_Polar_Strat_Cloud
AODSOAfromAqIsoprene550nm: Column_AOD_SOA_from_Aqueous_ISOP
AODStratLiquidAer550nm: Column_AOD_Strat_Liquid_Aerosol
AODTotal: Column_AOD_Total

And here is a sample AOD plot from the benchmarks.

[yantosca]

Also, AODTotal is computed in our GCPy plotting code. The other diagnostic names are as listed in the HISTORY.rc file. Hope that helps!

[theloniuspunk]

Hey Bob,

Can you point us to who developed these diagnostics? Cloud optical depths are - by definition - not aerosol optical depths and should not be included in the aerosol optical depth. Also, the hydrophobic BC and OC (BCPO and OCPO) should be included in the aerosol optical depth.

Thanks!

Jeff

[yantosca]

So I believe the netCDF diagnostics are just analogs of the original bpch diagnostics. We tried to get the netCDF to mimic the same outputs from the bpch.

I think @lizziel did some of the work to translate those diagnostics from bpch to netCDF. Some of that work was also probably done by me as well.

[yantosca]

Also tagging @msulprizio @sdeastham

[theloniuspunk]

Thanks, Bob. They seem different than what we used to use for ND49 and ND51, but maybe they are the same as what used to come with the monthly output? @kbilsback Is this what you're thinking?

[kbilsback]

@theloniuspunk Yes, I am looking for the aerosol optical tracers that used to be output from the ND49/ND51 menu (num. 517-522). It looks like the AOD diagnostics above (from the HISTORY.rc Aerosols menu) were originally in the ND21 cloud diagnostics. It looks like the ND49/ND51 aerosol optical depth diagnostics do not currently not have a netCDF equivalent. Unless I'm missing something?

[yantosca]

The ND49 diagnostics were removed I think in 12.6.0 and later, as you can now schedule any diagnostic with instantaneous frequency.

I took a look at the diagnostics in the diag51_mod.F90. Here is the code for archiving the sulfate AOD:

https://github.com/geoschem/geos-chem/blob/dc499905328a4821de1b85b9ee67b8b1d95e61d0/GeosCore/diag51_mod.F90#L726-L751

and here is the code for archiving sulfate AOD from aerosol_mod.F90.

https://github.com/geoschem/geos-chem/blob/dc499905328a4821de1b85b9ee67b8b1d95e61d0/GeosCore/aerosol_mod.F90#L2063-L2156

I think these are equivalent. Normally (unless you are using RRTMG), W=1. Also for sulfate N=1. So for the case of LINTERP=.FALSE. (which I believe is the default since we do not interpolate between 2 wavelengths in the out-of-the-box code), so we are archiving the quantity

(ODAER(I,J,L,IWVSELECT(1,1),1)

in the diagnostic slot for sulfate AOD in both the ND51 bpch code and the aerosol_mod.F90 code. Etc. for the other AOD quantities.

[kbilsback]

So if I understand correctly, the AOD tracers that used to be output with ND49 should be equivalent to what's output with the aerosols menu in HISTORY.rc. Thank you!