Belle-Île-en-Mer: the perfect field site for studying wind-wave interactions

The last time we left Boris Conan, Pascal Keravec and Kelsey Everard, researchers at the LHEEA (Laboratory for Research in Hydrodynamics, Energy and Atmospheric Environment) at Centrale Nantes, they were installing three LiDARs (measuring devices) at Pointe du Talut of Belle-Île-en-Mer to measure wind as close as possible to the water’s surface.

This project, called PRAMAG and funded by the National Research Agency (ANR) and the Defense Innovation Agency (AID), aims to observe the interactions between wind and waves, and especially the transfer of energy from waves to the wind. Indeed, while wind blowing over the sea generally generates swells, sometimes, even after the wind dies down, the swells persist and can have a feedback effect on the atmosphere.

The two campaigns, conducted in the spring of 2026, involved measuring wind characteristics at sea using Ocarina, a trimaran approximately 1.50 m long and equipped with a wide array of measuring instruments developed by the MIO. To do this, the researchers deployed the instrument off the coast of Belle-Île, near the wave-recording buoy, and let it drift for several hours under various sea conditions. To support this effort, the scientists continued to use LiDAR systems, which measure wind turbulence from the surface up to 150 m above the sea, as well as other instruments deployed on-site to observe all atmospheric variables necessary for understanding wave-wind interactions.

Ultimately, these measurements will help advance our understanding of physics, improve climate forecasting, and optimize the design of floating wind turbines. They may also be used in the defense sector to better estimate radar range.

OCARINA in the water for current measurements, with a spotter buoy for waves.

The zodiac research team setting out to deploy OCARINA near the wave-recording buoy