l2gen gas_opt question

alaroy · by **alaroy** » Tue Apr 09, 2019 6:29 pm America/New_York

Good evening SeaDAS'ers :)

I'm wondering - when using l2gen, what is the difference between gas_opt=8 (noted as "H2O" in the usage message) and gas_opt=16 (noted as "use atrem (H2O)" in the usage message)?

Thank you in advance for your help!

-Andrew L.

by **OB.DAAC - SeanBailey** » Tue Apr 09, 2019 6:57 pm America/New_York

The way the gas correction is applied. If gas_opt=16, an implementation of ATREM is used. It is intended only for hyperspectral sensors with bands that can include significant gaseous absorption - particularly water vapor. Most sensors supported by l2gen do not require (or can even make use of) this option.

Sean

alaroy · by **alaroy** » Wed Apr 10, 2019 11:01 am America/New_York

Thank you, Sean, for the quick response!

I'm guessing MODISA's 841-876 nm band is not one that can can benefit / use ATREM.

by **OB.DAAC - SeanBailey** » Wed Apr 10, 2019 12:12 pm America/New_York

yep...