Breaking waves and their effects on near surface sound speed

An autonomous sound speed profiler buoy was built and deployed in the North Atlantic, winter 1993-94, as part of the ASREX (Acoustic Scattering and Reverberation Experiment) experiment. 43 days of data were recovered which includes several short storm cycles (2-3 days each) with 7 storms having sustained winds greater than 15 m/s. Near surface sound speed measurements made in the first 7 meters of the water column reveal large sound speed reductions that are a result of air injection due to breaking waves. The relationship between low frequency sound speed and void fraction of air in water (Wood 1941) make the resulting data useful for both oceanographers and acousticians studying the air-sea interface. A description of the buoy system and a discussion of the data is presented.