Ten years of Advancing Forest Disturbance Monitoring with Sentinel-1 radar
Over the past decade, Sentinel-1 has become vital for radar-based forest disturbance monitoring. Its cloud-penetrating radar delivers consistent, gap-free observations every 6–12 days in the tropics and nearly daily in northern latitudes, enabling reliable near-real-time monitoring even in cloudy regions. With 10 m detail and sensitivity to vegetation structure, Sentinel-1 has transformed detection of fine-scale disturbances like small-scale farming, road building, and selective logging.
We show how Sentinel-1 has advanced forest monitoring. Early efforts developed near-real-time change detection, demonstrating that frequent observations can offset C-band radar’s lower sensitivity. Open data access, combined with cloud computing and open-source tools, allowed us to scale up methods into the operational Radar for Detecting Deforestation (RADD) alerts. Updated weekly and covering 55 pan-tropical countries, RADD alerts are freely available through Global Forest Watch and support law enforcement, supply chain monitoring, and research.
We also share lessons from expanding RADD to new regions, including Europe. Advances include radar texture-based detection, monitoring in temperate and boreal forests, and monthly road mapping. New developments enable tracking of forest loss drivers and intra-annual carbon loss, and continental-scale commodity mapping. Future improvements will benefit from combining Sentinel-1 with optical sensors and upcoming radar missions (NISAR, BIOMASS).
