Earthdata Forum

Hello all,

I'm trying to run l2gen (9.11.0-V2025.1) over a Sentinel-2B image, but using even the basic command line requests a gas transmittance file as input. I tried:
l2gen ifile=/home/matheus/Documents/GET/py_data/S2L1C/S2B_MSIL1C_20240606T143749_N0510_R096_T20LLQ_20240606T161957.SAFE/manifest.safe ofile=/home/matheus/Documents/GET/SeaDAS/20240606/SeaDAS_20240606.nc

and get this error:
-E- clo_getOptionString: option=gas_transmittance_file needs to be set

In previous versions of l2gen, this option was not mandatory. So I'm wondering where can I get this file? Donwloading the ancillary data using getanc donwloads meteorological data, but I don't think this is the correct input.
Thanks for the help!

Matheus Tavares

Sorry about that. We do not have a gas transmittance table for MSI yet.
Just put this on the l2gen command line or par file.

gas_transmittance_file=none

don

Thank you for your response.
Adding this piece of code, I could run l2gen but it didn't produce results (Flag #31: PRODFAIL 30140100 100.0000), possibly because of the configurations I need for my study area (Madeira river in the Amazon). Therefore I tried this code:

l2gen ifile=/home/matheus/Documents/GET/py_data/S2L1C/S2B_MSIL1C_20240606T143749_N0510_R096_T20LLQ_20240606T161957.SAFE/manifest.safe ofile=/home/matheus/Documents/GET/SeaDAS/20240606/SeaDAS_20240606.nc oformat=netcdf4 atmocor=on mode=0 aer_opt=-3 aer_wave_short=864 aer_wave_long=1611 glint_opt=1 brdf_opt=0 gas_opt=32 met1=/home/matheus/Downloads/SeaDAS/ocssw/var/anc/2024/158/GMAO_MERRA2.20240606T140000.MET.nc met2=/home/matheus/Downloads/SeaDAS/ocssw/var/anc/2024/158/GMAO_MERRA2.20240606T150000.MET.nc met3=/home/matheus/Downloads/SeaDAS/ocssw/var/anc/2024/158/GMAO_MERRA2.20240606T150000.MET.nc ozone1=/home/matheus/Downloads/SeaDAS/ocssw/var/anc/2024/158/GMAO_MERRA2.20240606T140000.MET.nc ozone2=/home/matheus/Downloads/SeaDAS/ocssw/var/anc/2024/158/GMAO_MERRA2.20240606T150000.MET.nc ozone3=/home/matheus/Downloads/SeaDAS/ocssw/var/anc/2024/158/GMAO_MERRA2.20240606T150000.MET.nc gas_transmittance_file=none

for which I get the following error:
-E- /home/dshea/ocssw/src/l2gen/gas_trans.c: Failed to open none

Does it mean that for the configurations I used l2gen can't run without the gas transmittance file?
Thank you again.

Matheus

Hi Matheus,

This issue should be resolved in an upcoming tag, T2025.8. Once released, you will be able to install this tag using the command install_ocssw --tag `cat $OCSSWROOT/.manifest_tag` --all.

I hope this helps!

Best,
Jakob

we have not generated gas transmittance tables for MSI. Your command will work if you get rid of "gas_opt=32".

don