Observations of Locally Generated Wind Waves using a Novel Airborne Polarimeter

Short wind-wave growth is central to estimating sea-surface drag and air-sea momentum transfer, as it increases surface roughness and facilitates directional wave breaking. Therefore, field observations that resolve the full wind-sea scale are essential for parameterizing air-sea fluxes and validating numerical weather prediction models.

In these efforts, we developed a measurement system with a polarimetric camera integrated into a UAV platform, leveraging RTK-enabled aircraft positioning and an inertial measurement unit for high-precision georeferencing. With varying altitudes, we resolve ocean waves ranging from centimeters to decameters, extending the polarimetric camera’s capabilities to those of wave buoys.

Field measurements were conducted from May to July 2025 on the coast of Rye, New Hampshire, under various conditions, including gusty winds, limited/unlimited fetch, and misaligned wind-swell and current. The observations yield 3D directional wave spectra, resolving wavelengths from 20 m to 6 cm and frequencies from 0.3 to 5 Hz. The directional spreading, current shear, and bimodal peaks are plotted against the mean current direction and wind speed, which were measured by a nearby buoy. With these measurements we aim to explore the dynamics of locally generated surface waves by linking the gravity capillary scales to larger wind-sea.