S3A and S3B negative Rrs_761, Rrs_764, Rrs_768

jcoca · by **jcoca** » Tue Jun 25, 2019 2:16 pm America/New_York

Hello
We are processing Sentinel 3A and 3B calling l2gen. We always get negative Rrs for band 761, 764 and 768 (see attached example). It happens for both satellites, and for both clear and turbid waters

Regards
Josep

by **OB.DAAC - SeanBailey** » Wed Jun 26, 2019 8:52 am America/New_York

Josep,

The 761, 764 and 768nm bands are not intended for use in ocean applications. These bands are in the oxygen-A band atmospheric absorption feature and are intended for estimating cloud top height. The additional (and rather strong) absorption by oxygen is not accounted for in the l2gen processing for these bands. We may eventually implement a correction for this gaseous absorption (a similar one is in place for the SeaWiFS 765nm band) but until we do (and I'm not guaranteeing we ever will) you probably just want to avoid these bands for ocean processing.

Sean

jcoca · by **jcoca** » Wed Jun 26, 2019 12:15 pm America/New_York

Hello Sean

Thank you very much for you prompt response.

Regards
Josep