Satellite Imagery Turns a Former Data Problem Into a Tidal Tool
Tide gauges are the standard tool for measuring water levels, but they can be few and far between. Researchers from DTU Space, Oxford University, the Technical University of Munich, and OHB have developed a way to use satellite images instead. By analyzing more than four decades of Landsat imagery, they found that local tidal fluctuations can be derived from shoreline movements that were previously dismissed as noise.
The new technique, published in Communications Earth & Environment, follows the boundary between land and water in thousands of images and combines this with information about beach slope. Earlier, such shoreline shifts were filtered out as digital interference; now they serve as a meaningful signal. This is especially useful in places with sparse monitoring networks, including Greenland and Bangladesh.
Why the New Method Matters
In a single bay, tide height can differ by about one meter over just a few kilometers. Conventional water-level sensors, however, are often spaced 50 kilometers or more apart, so these variations are easy to miss. In Denmark, tidal changes are small, but Greenland experiences daily water-level swings of 5–6 meters despite having very few measurement stations. The approach also matters for Bangladesh, where tides interact with wind and river discharge to shape the risk of large-scale flooding.
Because the method separates daily tidal cycles from long-term shoreline changes, it could improve assessments of global sea-level rise as well. The study, identified by DOI 10.1038/s43247-026-03943-9, has the potential to reshape water-resource monitoring and management around the world. It also highlights how previously unused satellite data can be integrated into traditional environmental monitoring, an important development for countries dealing with climate-related flood risks.
This innovative approach to tidal tracking complements recent efforts to create a detailed tidal map for various beaches, showcasing how satellite imagery can revolutionize our understanding of coastal dynamics. By integrating these technologies, researchers are paving the way for more accurate assessments and improved resource management in vulnerable regions.