Measurements of breaking waves using a unique free-floating spar buoy

During recent UK-SOLAS funded cruises of the RRS Discovery a 10 m spar buoy was deployed in the North Atlantic to make direct measurements of wave breaking and subsurface bubble cloud populations. Measurements made from instrumentation on the buoy will be used to develop an improved parameterization of wave breaking and its contribution to gas exchange.

The buoy was equipped with both still and video cameras, and with 3 capacitance wave wires. There were also 3 acoustic transducers and 3 hydrophones arranged along the length of the buoy in order to measure accurately the bubble cloud populations. In addition, the buoy carried tilt meters and 3-component accelerometers to measure the motion of the buoy; specifically included to determine the possible effects of the long waves on the performance of the buoy, and on the wave measurements by the capacitance wires.

Wave breaking will be determined from the capacitance wire wave data (building on earlier work by Longuet-Higgins & Smith, 1983) and will be verified using pictures from the still and video cameras. Initial results from the buoy and progress in developing a wave breaking detection algorithm will be presented.