Field measurements of wind wave kinematics

Measurements have been performed of surface elevation and internal velocities in the frequency range of wind-generated waves at a location in the southern North Sea, 10 km off the Dutch coast, where the depth is about 17 m. Velocities were measured at two different elevations, viz. approximately 9 m and 12 m above the sea bed. The data cover a wide range of conditions of wind and sea, from young sea to old swell, including mixed cases. Significant wave height reached values up to 3.7 m, whereas the most energetic frequency band typically extended from 0.1 Hz to 0.2 Hz. The data have been analyzed mainly with respect to spectral transfer functions, in an effort to verify linear theory predictions.