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Fix ERA5 DATM shortwave band handling.#7

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ezhilsabareesh8 merged 2 commits into
cdeps1.0.92-xfrom
update-era-datamode-cdeps
May 17, 2026
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Fix ERA5 DATM shortwave band handling.#7
ezhilsabareesh8 merged 2 commits into
cdeps1.0.92-xfrom
update-era-datamode-cdeps

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@ezhilsabareesh8 ezhilsabareesh8 commented May 15, 2026 •
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ERA5 ssrd is an accumulated energy field in J m-2, while MOM/CICE require shortwave band fluxes in W m-2. The previous ERA5 datamode incorrectly treated albedo-like stream fields as shortwave flux bands, producing near-zero shortwave reaching MOM/CICE.

This PR:

  • Converts ERA5 ssrd to flux with / 3600.
  • Constructs Faxa_swvdr, Faxa_swndr, Faxa_swvdf, and Faxa_swndf from fixed physical partitions of ssrd_flux.
  • Removes unused ERA5 albedo-like shortwave stream dependencies from the datamode.

Specific notes

CDEPS Issues Fixed (include github issue #): ACCESS-NRI/access-om3-configs#548 (comment)

Any User Interface Changes (namelist or namelist defaults changes): Changes made in datm.streams.xml and generate_xml_datm_era5.py

@ezhilsabareesh8 ezhilsabareesh8 marked this pull request as ready for review May 15, 2026 01:43
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anton-seaice commented May 15, 2026

@NickSzapiro-NOAA - does UFS use the ERA5 datamode in CDEPS ?

We've found these lines to calculate sw in vis/ifrared/direct/diffuse bands don't work and the resulting incoming shortwave is much too low.

https://github.com/ESCOMP/CDEPS/blob/648807485bfc4924eeeb9c45f2b62753611f4dc9/datm/datm_datamode_era5_mod.F90#L415-L420

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NickSzapiro-NOAA commented May 15, 2026

Yes ... but I think those lines are essentially unused as variables are overwritten in the ! convert J/m^2 to W/m^2 below that.
Ufuk commented some extra context at ESCOMP#376 (comment)

The changes here look similar to ESCOMP#396 , fyi

anton-seaice
anton-seaice approved these changes May 17, 2026
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thanks @ezhilsabareesh8 - looks good. There are changes in https://github.com/ESCOMP/CDEPS/pull/396/changes#diff-0a1e5c02cd97ca2321696366949659240515762a42078d5a0e0eaaaa02f817b0 to swnet to but we don't use that, so that's ok for now!

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anton-seaice commented May 17, 2026

Thanks @NickSzapiro-NOAA - that's very useful!

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ezhilsabareesh8 commented May 17, 2026

Thanks @anton-seaice and @NickSzapiro-NOAA, merging this now.

@ezhilsabareesh8 ezhilsabareesh8 merged commit 6a21caa into cdeps1.0.92-x May 17, 2026
This was referenced May 18, 2026
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@ezhilsabareesh8 @anton-seaice @NickSzapiro-NOAA