Sentinel-2 is a key component of Europe’s Copernicus programme. The European Commission sets goals and funding for Copernicus, while the European Space Agency (ESA) is in charge of executing the programme in partnership with European organizations and national agencies. The European Meteorological Satellite Organization (Eumetsat) and the European Centre for Medium-range Weather Forecasts (ECMWF) are also integral to Copernicus.
ESA is responsible for operating the ground segment of the Sentinel-1, Sentinel-2 and Sentinel-3 missions and the Sentinel-5P satellite, which collect thousands of images every day. Data from these missions are freely accessible, with the ambitious goal of better understanding our planet and improving quality of life for Europe’s citizens.
CNES has acquired renowned expertise in optical Earth-observing satellites through its SPOT programme. The agency provided its know-how for the software used to process raw Sentinel imagery and for in-flight instrument calibration, notably during the in-orbit commissioning phase prior to entry into operational service. CNES is also making Copernicus data available to the general public and organizing campaigns to enable future applications to exploit Sentinel-2 data effectively.
Sentinel-2 ‘raw’ imagery—also known as Level 1A imagery—is not accessible to the general public. The data retrieved by ground servers must first be pre-processed, geolocated and normalized. CNES provides a tool via its PEPS platform for viewing and downloading Level 1C tiles with geometric and top-of-the-atmosphere reflectance corrections. PEPS also makes available Level 2A ground reflectance data corrected for atmospheric effects using ESA software.
CNES also distributes Sentinel-2 ground reflectance data through its Theia land surfaces data centre, but these are processed using the MAJA software developed by the CESBIO biosphere research centre since 2005 with the German space agency DLR. MAJA reflectance products rely on the historical data record to improve corrections and provide precise water, cloud and cloud shadow masks.