Support for benthic PAR in OCSSW v2026.4

[d.carrascorivera]

Hi OCSSW / SeaDAS Team,

I am attempting to process MODIS-Aqua Level-1A data over the Great Barrier Reef (GBR) region using OCSSW (v2026.4 / l2gen Version 10.3.0).When passing our legacy GBR parameter file containing custom benthic light flags (parb, iparb, Breflectfile, and Elev_auxfile), l2gen immediately exits with an invalid argument error:

--
Loading command line parameters
Loading user parameters for MODISA

-E- Invalid argument "elev_auxfile"
Elev_auxfile (string) (current=/export/home/a-e/dcarrasc/GBRODP/common/gbr100.grd) (source=.../l2.par)
--

Are benthic PAR (parb/iparb), bottom reflectance (Breflectfile), and custom elevation grid inputs (Elev_auxfile) supported in any official distribution or branch of OCSSW v2026.4?

If these flags are deprecated or unmerged custom parameters in standard l2gen, is the recommended NASA approach to output spectral Rrs and Inherent Optical Properties (IOPs) to derive bottom irradiance via external post-processing?

OS: Linux (HPC / WSL)
OCSSW Version: v2026.4 (l2gen 10.3.0)
Sensor: MODIS-Aqua

Thank you for your assistance!

[OB SeaDAS - dshea]

The param you are looking for is:

dem_auxfile (ifile) = auxiliary digital elevation map file

Not sure when elev_auxfile was changed.

don

[d.carrascorivera]

Hi Don,

Thank you for clarifying dem_auxfile!

Could you also clarify the expected product names (L2prod=) for benthic/bottom PAR and bottom reflectance in v2026.4? When we pass our legacy product names bpar and ibpar (also tried parb and iparb) under L2prod=, l2gen throws an unrecognized product error:

--
-E- l2gen: product bpar not found
--

Are benthic PAR outputs supported directly in l2gen under a different L2prod string?

Thanks again for your help!