The suite of Sentinel-3 missions from the European Union Copernicus programme is expected to provide long-term series of ocean colour data from the Ocean and Land Colour Imager (OLCI) to monitor the state of the oceans. The consistency of the OLCI standard products is analysed by presenting a comparison of the level-2 daily remote sensing reflectance RRS data from Sentinel-3A and Sentinel-3B (S-3A and S-3B) at pixel level over the global ocean and multiple years. Regardless of camera number, a remarkable level of agreement is found for RRS and the aerosol products during the tandem phase, an early stage of the S-3B mission when the spacecraft was placed on the same orbit as S-3A. This agreement is degraded after S-3B reached its final orbit, with much more scatter in the comparison and the appearance of systematic differences between S-3A and S-3B data that depend on the camera pair considered. For the most eastern viewing cameras (3 to 5), RRS at short wavelengths and the aerosol optical thickness at 865 nm tend to be larger, and the Angstrom exponent lower, than for the western viewing cameras (1 and 2). Possible impacts of the geometry of illumination and observation and of glint conditions are investigated. Further looking for elements that could explain cross-camera issues (knowing that they are similarly affecting both missions) and analyzing the behavior of the atmospheric correction in the near-infrared (starting with the aerosol products) are recommended avenues of investigation to improve the OLCI data record.

MELIN Frederic;  CAZZANIGA Ilaria;  GOSSN Juan; 

2026-05-28

ELSEVIER SCIENCE INC

JRC144569

1879-0704 (online),   

https://doi.org/10.1016/j.rse.2026.115479,    https://www.sciencedirect.com/science/article/pii/S003442572600249X,    https://publications.jrc.ec.europa.eu/repository/handle/JRC144569,   

10.1016/j.rse.2026.115479 (online),