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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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Could the GEOS-Chem photolysis mechanism calculate Lyman-alpha photolysis at 121.57 nm? #2445

Open Liyl2 opened 2 weeks ago

Liyl2 commented 2 weeks ago

Your name

Yali LI

Your affiliation

Southern University of Science and Technology

Please provide a clear and concise description of your question or discussion topic.

I'm using GCClassic 14.0.2 with Fast-JX v7.0a photodissociation mechanism, which considers 177-850nm and divides into 18 bins, and in the Jvalue diagnostics I get the radiative fluxes for each bin (e.g., UVFluxnet_187nm, UVFluxDiffuse_187nm, and UVFluxDirect_187nm). Using the Fast-JX mechanism, can I calculate Lyman-alpha (121.57nm) photolysis? How do I get the radiant flux at 121.57nm? Looking forward to your reply, thanks!

yantosca commented 1 week ago

Thanks for writing @Liyl2. I believe that FAST-JX and Cloud-J are not set up to compute photolysis at Lyman alpha. You might need to use a standalone radiative transfer model (e.g. LIDORT) to compute other wavelengths. We would not be able to advise you further.

Tagging @lizziel in case she has any more suggestions.

lizziel commented 1 week ago

I concur with @yantosca. The minimum wavelength in FJX_spec.dat used for FAST-JX and CLOUD-J in GEOS-Chem is 187 nm.

@pratherUCI - do you see expansion to Lyman-alpha as a possibility for Cloud-J in the future?