Level 2A Sentinel-2 data are generated from all available level 1C acquisitions using the Sen2Cor processor (v2.3). This preprocessing step is the basis for a range of higher-level products that make use of the Sentinel-2 reflectance data, such as the vegetation and land-use dynamics products.
The Sen2Cor processor is a third party plugin designed for for Sentinel-2 Level 2A product generation and formatting. It creates Bottom-Of-Atmosphere (BOA) reflectance images by performing an atmospheric correction of the Top-Of-Atmosphere (TOA) data employing ATCOR. Currently, a terrain as well as a cirrus correction are done in Sen2Cor. As byproducts of the atmospheric correction, Aerosol Optical Thickness (AOT), Water Vapor Pressure (WVP), scene classification maps and quality indicator mapss for cloud and snow probabilities are generated, which can be useful for further image masking. The organization structure of the output product format is equivalent to the Level 1C User Product (i.e. JPEG 2000 images at two different resolutions, 10 and 20 m). Copernicus Sentinel data [2015 – 2017].