Earthdata Forum

Dear Support,
I am interested in using l2gen on lakes. I'd like a confirmation on the use of the atmospheric pressure. From the source code, I understand that the pressure used is always the sea level pressure (from MERRA files) to which is applied an exponential correction if proc_land=1 (default) and height >0 . So l2gen in default mode applies an atmospheric correction with a corrected pressure (for the lake altitude). Is this correct ?
A secondary question: when processing OLCI, if MERRA files are given in the l2gen parameter file, l2gen will use the MET data of MERRA and not OLCI's MET data, correct?
Thanks a lot for confirming!
Best
F.

Frederic,
Yes, by default l2gen corrects for atmospheric pressure, even over high altitude lakes (if proc_land is on, which it is by default). And yes, processing for OLCI uses the input MERRA2 ancillary data, not the ancillary included with the OLCI L1B files.

Regards,
Sean