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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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Fix a bug in coarse-mode seasalt Ca, Mg, and K #2489

Closed yc-chan closed 1 month ago

yc-chan commented 1 month ago

Name and Institution (Required)

Yuk Chun Chan (UW) and Becky Alexander (UW)

Describe the update

In the past, GC only called ISORROPIA for doing fine-mode-aerosol calculations, so it assumed all the Ca, Mg, and K in aerosols are from fine-mode seasalt. However, DO_ATE is now used for coarse-mode-aerosol calculations as well so we have to update the code for that.

After this bug fix, GC will use SALC instead of SALA to calculate the contribution of seasalt to coarse-mode Ca, Mg, and K. Note that the alkalinity factor AlkR is now included in the formulas to make sure these cations are treated the same way as Na.

Expected changes

Without this fix, I expect that GC will likely underestimate cation abundance in coarse-mode aerosols in marine boundary layer, especially after the previous correction to Na-to-seasalt mass ratio.

Related Github Issue

Comment back in Ca, Mg, and K cations in aerosol thermodynamics #2391

yc-chan commented 1 month ago

What about "Introduced seasalt Ca, K, Mg back to aerosol thermodynamics via HETP." ?

I am not familiar with the convention for Changelog. How detailed do we need usually?

lizziel commented 1 month ago

That update sounds good. Could you push the change to your branch?

yc-chan commented 1 month ago

Done!

msulprizio commented 1 month ago

This pull request passes all GCClassic and GCHP integration tests