Sentinel-2 Level-2 processing: Regional distribution of Sen2Cor version 2.8 performance for AOT and SR retrieval over Europe

Abstract

Sen2Cor is the atmospheric correction processor selected by ESA for operational, systematic processing of Copernicus Sentinel-2 mission data. It is used for generating the Level-2A products distributed to users by the Copernicus SciHub. In addition, it can be downloaded from ESA website as standalone tool for individual processing by the users. The main purpose of Sen2Cor is to correct mono-temporal Sentinel-2 (S2) Level-1C (L1C) products from the effects of the atmosphere in order to deliver atmospherically corrected Bottom-of-Atmosphere (BOA) respectively surface reflectance (SR) data. Part of the atmospheric correction process is estimation of aerosol optical thickness and integrated water vapor of the atmosphere. Provided SR data are used in a wide field of downstream applications on land surface related to agriculture, forestry and land-cover change and are also used to monitor coastal and inland water. Downstream applications need information on quality of atmospheric correction products. This presentation will show performance of AOT and WV retrievals estimated by comparing with reference data provided by AERONET sun photometers at different locations distributed over Europe. Spatial average of retrievals from Sentinel-2 over 9x9 km2 region around AERONET station is compared to ±15 min time average of AERONET data around satellite overpass time. Performance of SR retrieval is assessed by comparison with pseudo reference data. These are generated by running Sen2Cor with fixed aerosol optical thickness as input which is set equal to the value provided by the AERONET.