ESA Tracks Mammoth Swells Across Indian Ocean

Dr Bertrand Chapron of IFREMER, the French Research Institute for Exploitation of the Sea, and Dr Fabrice Collard of France's BOOST Technologies in Brest located and tracked the swells using standard processed Synthetic Aperture Radar (SAR) ESA Wave Mode products, as shown in the animation above.

"The extreme swell systems originated from the same storm, which moved rapidly and had two main strong wind periods," Chapron said. "As illustrated in the animation, the resulting waves were organised into two main swell systems that followed each other across the entire Indian Ocean, hitting Reunion Island, Mauritius, Australia and Indonesia."

"Although swells are still surprise factors, these particular swells were created by natural events so they could be tracked," Chapron said. "By using the SAR Wave Mode product, we can locate and systematically track swells globally, making it possible to put a network of early warning systems in place in the near future."

"Because of its unique capacity to restitute wavelength and directional information of the propagation of swells, the SAR instrument is about to bring a remarkable contribution to the monitoring of energetic wave systems," Collard said.

Today, the ASAR Wave Mode acquires 10 by 5 km small images, or 'imagettes', of the sea surface every 100 km along the satellite orbit. These small ‘imagettes’ are then mathematically transformed into averaged-out breakdowns of wave energy and direction, called ocean-wave spectra, which ESA makes available to scientists and weather centres.

As part of the Global Monitoring for Environment and Security (GMES), a joint initiative of the European Commission and ESA, the space agency has undertaken the development of Sentinel-1, a European polar-orbiting satellite system for the continuation of SAR operational applications