Monitoring coasts
Our coasts are subjected to changing ocean conditions, with rising sea level, more frequent storms, extreme weather events and erosion to name a few. Coasts must be monitored and protected for their economic and ecological value. Satellites have a key role to play in this task.
Here, near Arcachon (Atlantic Ocean, France), erosion is being closely monitored after the big storms of January 2014.
Virginie Lafon, Geo Transfert, University of Bordeaux: "We’ve been using satellite data to map the Aquitaine shoreline since the start of the century. We started with Spot data and now, since 2012, we’re using very-high-resolution Pleiades data that give us a much more precise picture. Erosion here is a chronic problem, to the extent that the shoreline is now receding. Between 2012 and 2013, Pleiades data revealed that it had receded by about 20 metres. In 2014, as a result of some very severe storms, shoreline retreat speeded up even more. The 2015 winter was much calmer and we can see now that the beach has been replenished."
Many new applications like shellfish ecosystem mapping, dune erosion monitoring and tracking and surveillance of tidal passes for navigation have emerged.
Cnes is increasingly using multiple sensors, including altimetry satellites.
Virginie Lafon, Geo Transfert, University of Bordeaux: "Altimetry satellites give us the mean sea level and we’re able to precisely calculate how much it’s rising every year as a result of climate change. New satellites like SWOT are set to bring us really precise altimetry data. We’ll get full-scene imagery showing sea level down to beach scale, and we’ll be able to precisely quantify a wealth of other oceanographic parameters like currents and waves to refine the models we use to predict the coast’s likely evolution"
Since 2013, the Saral satellite’s new Ka-band altimeter has provided a more precise picture near coastlines. This is an intermediate step before the arrival of the Swot satellite and its new radar interferometer.
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