Add AIRS Spectral OLR

[chengzhuzhang]

Description

Add AIRS Spectral OLR Support

Summary

This PR adds support for AIRS spectral OLR (Outgoing Longwave Radiation) observations in e3sm_diags, enabling model evaluation against both broadband and spectral OLR measurements in specific wavenumber bands. Data and script prepared by Professor Xianglei Huang (@XiangleiHuang) 's group at UMICH. closes #1011

Changes

1. Data Processing Script (analysis_data_preprocess/process_airs_spec_olr.py)

• New script to process raw AIRS spectral OLR data from AIRS2CERES and AIRS2MODIS sources

• Converts spectral OLR to E3SM band definitions:

  • Band 02: 350-500 cm⁻¹ (sensitive to upper/middle troposphere)

  • Band 06: 820-980 cm⁻¹ (sensitive to surface PBL moisture)

• Generates climatology files using xcdat's temporal methods:

  • Monthly climatology (12 months)
  • Seasonal climatology (DJF, MAM, JJA, SON)
  • Annual mean (ANN)

• Outputs both all-sky and clear-sky fluxes for broadband and spectral bands

2. Variable Derivations (e3sm_diags/derivations/derivations.py)

• Added new E3SM variables:
  • FLSU02: Spectral OLR band 02 (350-500 cm⁻¹), all-sky
  • FLSU06: Spectral OLR band 06 (820-980 cm⁻¹), all-sky
  • FLSUCLR02: Spectral OLR band 02 (350-500 cm⁻¹), clear-sky
  • FLSUCLR06: Spectral OLR band 06 (820-980 cm⁻¹), clear-sky
  • Spectral ratios with respect to broadband LW counterparts.
• Updated existing variables:
  • FLUT: Added AIRS broadband all-sky OLR (olr)
  • FLUTC: Added AIRS broadband clear-sky OLR (olr_clr)

3. Lat-Lon Diagnostics Configuration (e3sm_diags/driver/default_diags/lat_lon_model_vs_obs.cfg)

• Added 6 new diagnostic sections for AIRS spectral OLR comparisons:
  • FLUT (broadband all-sky)
  • FLUTC (broadband clear-sky)
  • FLSU02 (band 02 all-sky)
  • FLSU06 (band 06 all-sky)
  • FLSUCLR02 (band 02 clear-sky)
  • FLSUCLR06 (band 06 clear-sky)
• All diagnostics configured with:
  • Reference dataset: AIRS_specOLR
  • Seasons: ANN, DJF, MAM, JJA, SON
  • Appropriate contour levels for each spectral band

Data Sources

• AIRS spectral OLR data provided by Professor Xianglei Huang's group at UMICH
• Data period: 2003-2021
• Processing converts AIRS spectral measurements to E3SM spectral band definitions

The diagnostics will automatically use the appropriate AIRS variables based on the E3SM model variable being evaluated.

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

If applicable:

• New and existing unit tests pass with my changes (locally and CI/CD build)
• I have added tests that prove my fix is effective or that my feature works
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have noted that this is a breaking change for a major release (fix or feature that would cause existing functionality to not work as expected)

[chengzhuzhang]

@XiangleiHuang, @brhillman and @crterai, this PR is ready to review. The results were first validated against those figures created by @XiangleiHuang 's group. The e3sm_diags implemented plotes can be viewed here.
Hi @XiangleiHuang thanks for your teams contribution! Could you review the results? Also as we discussed earlier, would be nice to include how best to interpret these new diagnostics. I'd like to add some notes when documenting this new diagnostics group, could you help with it?
@brhillman This current implementation only applies to EAM output variables, could you point to me what are the equivalent variable names for EAMxx, so that those can be supported as well.

[XiangleiHuang]

Hi Jill, Thanks. Xiuhong and I will review it and let you know. Yes, we will creat a video and powerpoint tutorial on how to use this diagnostics. I have a proposal deadline this week, will try to finish it next week. Happy New Year! Xianglei

…

On Mon, Jan 5, 2026 at 3:14 PM Jill Chengzhu Zhang ***@***.***> wrote: *chengzhuzhang* left a comment (E3SM-Project/e3sm_diags#1031) <#1031 (comment)> @XiangleiHuang <https://github.com/XiangleiHuang>, @brhillman <https://github.com/brhillman> and @crterai <https://github.com/crterai>, this PR is ready to review. The results were first validated against those figures <https://portal.nersc.gov/cfs/e3sm/chengzhu/tests/1031-airs-spec-olr/fig/> created by @XiangleiHuang <https://github.com/XiangleiHuang> 's group. The e3sm_diags implemented plotes can be viewed here <https://portal.nersc.gov/cfs/e3sm/chengzhu/tests/1031-airs-spec-olr/viewer/lat_lon/index.html> . Hi @XiangleiHuang <https://github.com/XiangleiHuang> thanks for your teams contribution! Could you review the results? Also as we discussed earlier, would be nice to include how best to interpret these new diagnostics. I'd like to add some notes when documenting this new diagnostics group, could you help with it? @brhillman <https://github.com/brhillman> This current implementation only applies to EAM output variables, could you point to me what are the equivalent variable names for EAMxx, so that those can be supported as well. — Reply to this email directly, view it on GitHub <#1031 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANOYHZACQMVCZ26CRWUUQ2D4FLA37AVCNFSM6AAAAACQLM4GMWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTOMJRHE2DAOBUGI> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[chengzhuzhang]

Thank you, @XiangleiHuang. No rush on this, hope the proposal is going well. Happy new year!