Level-1C data

The Level-1C Top-of-Atmosphere (TOA) reflectance data are downloaded from the Copernicus Data Space Ecosystem. Level-1C is an ortho-image product, i.e., a map projection of the acquired image using a system Digital Elevation Model (DEM) to correct for ground geometric distortions. Radiometric observations are provided as reflectances, with all relevant parameters to transform them into radiances available. Level-1C data are resampled with a constant Ground Sampling Distance (GSD) of 10 m, 20 m, and 60 m, according to the native resolution of the different spectral bands, see the Sentinel-2/MSI instrument description.

The Level-1C data processing includes:

• geometric corrections
  • sub-pixel multi-temporal registration between images
  • resampling using a 90 m DEM (PlanetDEM 90)
• radiometric processing
  • conversion to reflectance
  • preview image generation and masks generation (defective pixels, clouds and land/water).

Level-1C data are provided as SENTINEL-SAFE files, which include image data in JPEG2000 format, quality indicators, auxiliary data, and metadata. Detailed information on the Level-1C data and processing is available at the ESA website.