How to get the reflectivity of the Sentinel Tripodium image

Hello everyone.After researching, it was found that the results of SNAP’s C2RCC tool were for water bodies, so I wanted to ask if the Sentinel 3 data level 1 product(OL_1_EFR) needed other corrections, such as atmospheric corrections. If the downloaded data needs to be processed, please also let us know the processing method, thank you.


What needs to be done depends on your use case. Often an atmospheric correction is needed, for which you can use iCOR for. There is also the Rayleigh correction (available in SNAP) which corrects for a major part of the atmospheric interference (comparison between iCOR and Rayleigh). Ther are several water constituents’ retrieval algorithms which include an AC specialised on water ( Evaluation of seven atmospheric correction algorithms for OLCI images over the coastal waters of Qinhuangdao in Bohai Sea - ScienceDirect).

In SNAP you find even other preprocessing steps for OLCI.

  • the O2A Harmonissation
  • the A/B Sensor Harmonisation
  • the PPE Filtering

What is needed depends on you use case and you need to decide. Some of those steps have a big impact, others only a small, and for others it depends on the conditions.

But there is also Level-2 data available. This can be a short cut for you. This data has been pre-processed already.

First of all, thank you, I will try the iCOR tool and conduct a detailed investigation of the Level 2 data for my research work.