[ISSUE] Potential typos on the "Species in GEOS-Chem" wiki page

[LukeFakes]

I've been looking at the wiki page for fine and coarse mode sea salt aerosol and chloride in sea salt (SALA, SALC, SALACL, SALCCL) and I'm not sure if there might be a couple of mistakes or I'm misunderstanding things.

• Molecular Weights for SALACCL and SALCAL. Should these be 35.45 (mass of Chloride) rather than 31.4, as in the species_database.yml file?
• The definition of Fine mode aerosols is 0.01-0.05 microns: Is that correct or should it be 0.01-0.5?

I also have one question relating to PM2.5 composition. Coarse mode sea salt aerosol is defined as 0.5-8 microns, so why is it not included in the formula for PM2.5? `PM25 = ( NH4 + NIT + SO4 ) * 1.10

• BCPI
• BCPO
• ( OCPO + ( OCPI 1.05 ) ) (OM/OC ratio) # OM/OC ratio = 2.1 by default
• DST1
• DST2 * 0.30 # F. Yu suggests 30% of DST2 (Nov 2011); prior value was 38% of DST2
• SALA * 1.86
• SOA * 1.05`

[yantosca]

Thanks for writing @LukeFakes.

1. There is a reason why SALACL and SALCAL are the MW of sea salt rather than chlorine but now I can't remember why. It may be because it is internally mixed. Tagging @beckyalexander and @msl3v.
2. Yes, SALA should be 0.1 - 0.5 and SALC is 0.5 - 8 um. I'll fix that.
3. We have used the PM25 definition provided to us by the Aerosols WG. Tagging @beckyalexander and @theloniuspunk.

Also note, a lot of the wiki doc hasn't been updated since 12.8.0. We are in the process of migrating the user manuals to our ReadTheDocs pages for 14.0.0 (https://geos-chem.readthedocs.org). We hope to be able to provide updated species documentation that is pegged to each GEOS-Chem version (perhaps by parsing the species database into a table or something,... it remains to be seen).

[theloniuspunk]

Not sure about #1. Maybe that's the average MW of the ions in sea-salt?

For coarse mode sea salt, where is it defined as 0.5-8 microns? Is that radius or diameter? I suspect it's radius, making diameter 1-16 um. Certainly 1 < 2.5, but I suspect that 1-2.5 um has a trivial fraction of the coarse-mode mass. I think that Fangqun's group was refining the fractions in this definition for sea-salt and dust using APM.

[yantosca]

@theloniuspunk The sea salt radius bin sizes are defined in input.geos. Soon to be geoschem_config.yml.

[theloniuspunk]

Thanks, Bob. I think my rational holds as to why SALC is left out of the PM2.5 calculation (only a tiny fraction of this mode had Dp < 2.5 um), but I think Fangqun's updated calculation should help.

[yantosca]

FYI, in anticipation of the 14.0.0 release, we have created a ReadTheDocs page for species information in GEOS-Chem. Basically we now rely on the species_database.yml for the most up-to-date info rather than the wiki page. See: https://geos-chem.readthedocs.io/en/latest/geos-chem-shared-docs/supplemental-guides/species-guide.html

Also tagging @Jourdan-He

[LukeFakes]

Hi @yantosca, thanks for letting me know that had been updated.

And thanks @theloniuspunk for giving further clarification

[yantosca]

I can close out this issue. We now have the species guide at ReadTheDocs that link to the most recent species database files.