Sun glitter helps monitor waves

Scientists are using sun glitter in images from the Copernicus Sentinel-2 satellite mission to map wave movement. Use of measurements of roughness from satellite sensors is not new, but by capturing the glitter of sunlight on water, Sentinel-2’s multispectral camera can provide a wealth of information about the direction, height and movement of waves. A team of scientists has developed a way to interpret the sun glitter, and then used this information to create a series of detailed images of wave patterns off the coast of Dorre Island in Western Australia. Building on this technique and through the European Space Agency’s (ESA) Scientific Assessment of Ocean Glitter project, the team was able to map how waves develop in regions where there are strong ocean currents. Team member Vladimir Kudryavtsev, of the Russian State Hydrometeorological University’s Satellite Oceanography Laboratory, told the European Space Agency, “We went on to test our method on the Agulhas Current, a historically treacherous current around the southernmost coast of Africa. “Using data collected in January 2016, we traced the behaviour of ocean waves and their interactions with currents. We found that ocean surface currents transform dominant surface waves, which are the tallest surface waves in a given area, driven by local wind and large-scale swells. They also showed how wave packets can be deflected and trapped by ocean surface currents, creating surface waves that are much higher than normal.” Two Sentinel-2 satellites are now in orbit, potentially doubling the amount of data available for using glitter to map ocean waves. The Copernicus program is managed by the European Commission.