EODC High Quality Sentinel-2 Services – Pre-processing and experimental testing of improved applications

Goal of the HQ-S2 project was the generation of pre-processing algorithms and workflows for Sentinel-2 (S-2) data that improve the quality of the ESA standard products in terms of geometric and radiometric quality including corrections for topographic related degradations, which are especially important in areas of high topographic undulations (e.g. the Alps). Based on the corrected data sets, long-time series of high-quality images with reduced atmospheric and cloud effects (cloud detection, removal of cloud shadows) were built using Landsat-8 (L-8) and available S-2 scenes. Based on these cross-sensor time series, three specific applications in the domains of agriculture, forestry and urban areas, were implemented, thus testing and demonstrating the quality of the improved data. The major goals and milestones of the project could be reached within the project duration.

The project results are the first step towards a novel high-quality user-oriented S-2 service potentially provided in the future via the EODC framework. As a prerequisite, the quality and accuracy of the ESA standard Sentinel-2 (S-2) L1C products in terms of geometric and radiometric calibration and correction will be investigated with a specific focus on areas with high topographic variations. Near-real-time (NRT) filtering will be applied to a image time series composed from S-2 and Landsat-8 data in order to fill observational gaps between cloud-free imagery and to remove artefacts due to (undetected) clouds and poor atmospheric conditions. HQ-S2 will take methods of data pre-processing implemented in the ESA S-2 toolbox and will further develop and extend these to meet the needs of the use cases and integrate and test these within the EODC Earth Observation data processing framework.