SAR and Optical Remote Sensing for Flood Mapping and Monitoring through GEE

The work explores the use of Synthetic Aperture Radar (SAR) and optical sensors on board the Sentinel-1 and Sentinel-2 satellites for mapping and monitoring the Earth's surface in response to flood events. The choice of SAR proves advantageous due to its ability to penetrate clouds, ensuring continuity in acquisitions even in adverse weather conditions. The Google Earth Engine (GEE) platform, which provides the opportunity to customize algorithms and scripts, is used to perform the analysis. The goal is to develop an integrated methodology for early warning and impact mitigation. Two case studies are here presented: the flood that affected Ravenna in May 2023 and the Apollo hurricane in Sicily in 2021. The results confirm the effectiveness of the proposed approach in monitoring and discriminating water-covered surfaces. Despite challenges in data processing and calibration, the approach proves to be a valuable monitoring tool. The integration of SAR and optical data provides a comprehensive view of the flood situation, confirmed by the convergence of information from both satellites and news services.