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GEOS-Chem "Science Codebase" repository. Contains GEOS-Chem science routines, run directory generation scripts, and interface code. This repository is used as a submodule within the GCClassic and GCHP wrappers, as well as in other modeling contexts (external ESMs).
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Possible fix needed: NITs and SO4s should be wet removed as coarse aerosol species. #1414

Closed msl3v closed 1 year ago

msl3v commented 2 years ago

Since wetscav_mod.F90 distinguishes between COARSE and FINE aerosol in calculating washout rates, it needs to be pointed out that neither NITs nor SO4s are washed out as coarse species. It seems this is changed simply by setting WD_CoarseAer: true in species_database.yml for these two species. Testing in the GEOS-CF system shows this has a significant impact on NITs and SO4s.

yantosca commented 2 years ago

Thanks for raising the issue @msl3v. Am tagging the Aerosols WG co-chairs: @theloniuspunk @beckyalexander @wporter

yantosca commented 2 years ago

Also tagging @Jourdan-He and @SaptSinha

beckyalexander commented 2 years ago

SO4s and NITs are course-mode aerosols and should be treated exactly like coarse-mode sea salt aerosols, including using the same molecular weight, etc as the coarse-mode sea salt aerosols. SO4s and NITs are essentially internally mixed with coarse-model sea salt aerosols.

yantosca commented 2 years ago

Thanks @msl3v and @beckyalexander. This could be a fix for 14.1.0, as it would only involve changing the species database metadata for those species. I'll tag it as such.

yantosca commented 2 years ago

Follow-up question: In the species_database.yml file, we have 

SALC_PROP: &SALCproperties
  DD_AeroDryDep: true
  DD_F0: 0.0
  DD_Hstar: 0.0
  Density: 2200.0
  Is_Advected: true
  Is_Aerosol: true
  Is_DryDep: true
  Is_WetDep: true
  Radius: 4.25e-6
  WD_AerScavEff: 1.0
  WD_KcScaleFac: [1.0, 0.5, 1.0]
  WD_RainoutEff: [1.0, 0.0, 1.0]
  WD_RainoutEff_Luo: [0.4, 0.0, 1.0]
...
NITs:
  << : *SALCproperties
  FullName: Inorganic nitrates on surface of seasalt aerosol
  Is_Photolysis: true
  MW_g: 31.4
...
SO4s:
  << : *SALCproperties
  FullName: Sulfate on surface of seasalt aerosol
  MW_g: 31.4

So in other words, the metadata listed under SALC_PROPERTIES are common to several species (BrSALC, ISALC, NITs, SALC, SALCAL, SALCCL, SO4s),

Should we apply WD_CoarseAer:True to:

  1. Just for SO4s and NITs, or
  2. To SALC_PROPERTIES (and thus it would carry over to all of the species listed above)

Because BrSALC is one of the species, do you have a sense if this would also significantly change the Bromine chemistry?

Also tagging @djxjacob for advice.

msl3v commented 2 years ago

Hey Bob, BrSALC already has "WD_CoarseAer: true" as an attribute, in addition to *SALCproperties, so it would not have an effect to add it to SALCproperties. It seems that all internally mixed SALC species have the correct attribute except NITs & SO4s.

yantosca commented 2 years ago

Thanks Mike (@msl3v). Will proceed.

yantosca commented 1 year ago

We can close this issue as PR #1426 has been merged into the GEOS-Chem 14.1.0 development stream.