OLCI Vicarious Calibration Coefficients

[juancho.gossn]

Hi,I'm processing OLCI L1B data to obtain Rayleigh-corrected reflectance (via l2prod=rhos_nnn). My question is: are the vicarious calibration gains reported at https://www.eumetsat.int applied to the TOA OLCI radiances with SeaDAS? If not, what would be the best way to apply them using SeaDas?Thanks!Juancho

[OB.DAACx - SeanBailey]

Juancho,

No, the gains reported in that document are not applied in SeaDAS processing.  You can include them in your processing via the option "gain":
The current defaults for OLCI are:
gain=[1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0]

You can change these to match the values in the Copernicus document.

Keep in mind that vicarious calibration is a system-level calibration, so the values in the Copernicus document may not be applicable for processing
TOA to L2 within l2gen.  Now, rhos will not be as affected (as it's only removing Rayleigh) but any biases between the Copernicus processing and the SeaDAS processing would be present.

Regards,
Sean

[juancho.gossn]

Thanks Sean!
I'm now encountering an error I hadn't had before, while processing rhos from OLCI L1B imagery:

-E- /home/swtest/ocssw/src/l2gen/smile.c:89: unable to open /home/juancho/seadas-7.4/ocssw/share/olci/cal/band_info_olci.txt for reading
l2genOlciProcess: 28: l2genOlciProcess: Syntax error: "done" unexpected

Neither "/home/swtest" nor "/ocssw/share/olci/cal" directories exist. Since I hadn't had problems before, is it possible that suddenly these directories disappeared??

I tried reinstalling the olci processor, just in case...
python install_luts.py --git-branch=v7.4 --olci
But hasn't solved the issue

Any suggestions will be kindly appreciated
Thanks!
Juancho

[gnwiii]

The first portion of the message refers to the source file on NASA's system used to build the software, so it is not surprising that you don't have "/home/swtest" on your system.   The path "$OCSSWROOT/share/olci/cal/band_info_olci.txt" is probably the new layout for SeaDAS-7.5.  Topic 6930 mentions that the new binaries for the matchup tool end up in $OCSSWROOT/bin so we seem to be in a period of transition from the old layout to the new.

[juancho.gossn]

OK, thanks. This means I'll have to wait till the transition period ends? Or is there something I can update/change for it to work?
I've retried today and it still throws the same error.

Thanks!

[gnwiii]

Can you restore version (branch) v7.4 from a backup?   You could try a fresh install using install_ocssw.py -b v7.4 ....  The post I mentioned was addressing a particular bug, and seems to say the old and new binaries can coexist.

[OB.DAACx - SeanBailey]

You can probably just grab the OCSSW_bash.env file, which still points to the old directory structure.
put this in your $OCSSWROOT directory and source it. 

Sean

[aewindle110]

Hi Sean,

I am looking to apply updated SVC gains to OLCI l2gen processing. Are the defaults for OLCI still all ones? Do you have any recommendations on what would be the correct SVC gains for OLCI using l2gen AC?

Thanks,
Anna

[OB.DAACx - SeanBailey]

Anna,
We've not released our "official" L2 processing yet (soon, I promise ), but if you want to use a set of gains for OLCI S3A consistent with l2gen, try these:

gain=[0.959728,0.972313,0.97156,0.96916,0.97636,0.97951,0.97705,0.975398,0.97344,0.97597,1.00562,0.9829,1.0,1.0,1.0,0.98989,1.0,1.01815,1,1,1]

Sean

[aewindle]

Hi Sean,

Thanks for providing the SVC gains for OLCI S3A. Would the gains for S3B be all ones?