How satellites helped
Tides affect beach access, recreation, and coastal safety, so broad tidal coverage is valuable. Researchers at the Technical University of Munich have now shown that ocean tides for any beach can be predicted using satellite imagery. The team combined Landsat's archival images from 1984 to 2026 with the CoastSat system to produce a high-resolution map of water-level changes along the Pacific Ring of Fire. This map documents sea-level variations every 100 meters of coastline across New Zealand, Australia, Japan, Hawaii, and the western shores of the Americas.
The new method works by converting the sideways movement of the waterline into vertical measurements of rising and falling sea levels. That allows tidal forecasts to be made for each specific beach. Michael Hart-Davis from the Technical University of Munich and colleagues analyzed satellite images that revisit the same point every 16 days, using CoastSat to compute the beach slope angle through trigonometry. Those data let them identify monthly tidal cycles over a 191-day period.
Traditional sea-level sensors collect data only at one fixed location, while altimeters perform poorly near land. The new technique is thus more accurate and much more versatile.
Why this matters
According to the paper, this approach could provide personalized tidal forecasts for individual beaches, which is important because tidal intensity can differ greatly even a few kilometers apart. The resulting map of sea-level fluctuations could be a key tool for studying and managing coastal ecosystems.
Beyond research, the method may strongly affect coastal communities, local economies, tourism, and ecological monitoring. Better tidal predictions would allow safer planning of beach activities and reduce hazards linked to rising water, including erosion and flooding. Fishing and other ocean-dependent industries could also benefit.
As researchers continue to leverage innovative technologies for environmental monitoring, another groundbreaking study has emerged, highlighting the extensive mapping of ocean algae across vast oceanic regions. This advancement not only complements the tidal mapping efforts but also underscores the importance of satellite imagery in understanding marine ecosystems. For a closer look at how AI has successfully charted algae over 43.8 million square kilometers, you can read more about this significant achievement.