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geoschem / geos-chem

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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Sulfate_mod, Chem_H2O2 convert unit mistake #2302

Closed CraigYEUNG closed 1 week ago

CraigYEUNG commented 3 months ago

While using GC14.3.0 Aerosol-only simulation, sulfate_mod.F90 use Chem_H2O2 by:

       DH2O2 = ( PH2O2m(I,J,L) / TS_EMIS * XNUMOL_H2O2 / CM3PERM3 ) &
               * DT / ( ALPHA * M )
       H2O2  = ( H2O20 / ALPHA + DH2O2 )

this is to convert unit of kg/m3 to molec/cm3/s

But I found that in dryrun downloaded Prodloss file, Prod_H2O2 unit is already molec/cm3/s. Thus, if still use XNUMOL_H2O2 / CM3PERM3, H2O2 concentration will be much higher.

yantosca commented 3 months ago

Thanks for writing @CraigYEUNG. This issue may have crept in during implementation of the KPP chemistry mechanism in the full-chemistry simulation (in v11-01). All of the prod/loss outputs are in molec/cm3/s as they are generated by KPP.

We can implement a fix for this in a future bugfix version. For now, you can remove the XNUMOL_H2O2 / CMPERM3 in your code. Thanks for alerting us to this!

We only benchmark the full-chemistry simulation, so we wouldn't have caught this. We look to users like you to provide us with bug reports for aerosol-only and other specialty simulations.

yantosca commented 1 week ago

We can now close this issue as PR #2413 is now merged into 14.4.3.