Early Validation of Sentinel-2 L2A Processor and Products

Kurzfassung

The Copernicus programme is a European initiative for the implementation of information Services dealing with environment and security, mainly based on observation data received from Earth Observation (EO) satellites. In the frame of this programme, ESA launched the Sentinel-2A optical imaging mission on 23th June 2015. This satellite delivers a new generation of optical data products designed to directly feed downstream services mainly related to land monitoring, emergency management and security. To ensure the highest quality of service for the Sentinel-2 mission, ESA set up the Sentinel-2 Mission Performance Centre (MPC) supported by several Expert Support Laboratories (ESL). This presentation reports early results of validation of the Sentinel-2 L2A processor Sen2Cor performed by the ESL-L2A. Sen2Cor Level 2A processing is applied to Top-Of-Atmosphere (TOA) Level 1C ortho-image reflectance products. Sen2Cor L2A outputs are a scene classification image, aerosol and water vapour maps and the ortho-image Bottom-Of-Atmosphere (BOA) corrected reflectance product. Scene classification is generated together with Quality Indicators for cloud and snow probabilities at 60 m resolution. In this poster we present the calibration and validation datasets used for our on-going L2A cal/val activities, covering different land cover types, different atmospheric conditions and including different latitudes in order to cover various solar angles and seasons. The already performed and on-going insitu campaigns for collecting atmospheric and ground reference data to support the L2A products validation are also described. The methodologies of calibration and validation are presented under the form of a workflow chart, showing the two steps validation approach for atmospheric correction (validation of aerosol optical thickness and water vapour estimates and the validation of BOA reflectance product), the validation approach for cloud screening and scene classification (stratified random sampling), and the interactions with the L2A processor calibration activities. Details are given about the specifics of each method. Finally, the results of Sen2Cor L2A products validation activities (at the time of the LPS 2016 conference) will be provided for the cloud screening and scene classification, as well as for the