Observation of high-frequency sound propagation in shallow water with bubbles due to storm and surf

• Published in: IEEE journal of oceanic engineering Vol. 25; no. 4; pp. 501 - 506
• Main Authors: Goodman, R.R., Caruthers, J.W., Stanic, S.J., Wilson, M.A.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2000; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic measurements; Acoustic propagation; Breaking; Bubbles; Cities and towns; Density; Dispersions; Earth, ocean, space; Exact sciences and technology; External geophysics; Frequency; Laboratories; Marine; Marine optics and underwater sound; Oceans; Physics of the oceans; Poles and towers; Sea measurements; Shallow water; Shores; Storms; Surf; Towers; Underwater sound; Water storage; Atlantic Ocean; North Atlantic; Surf; Storm; Sound propagation; Spatial coherence; Air bubble; Temporal coherence; High frequency; Underwater acoustics; Shallow water; Dispersion; Wave breaking
• ISSN: 0364-9059; 1558-1691
• DOI: 10.1109/48.895357

An experiment was performed off the shore of Panama City, FL, to measure the spatial and temporal coherence of high-frequency signals that were transmitted between fixed towers. Transmission was along paths at mid depths in about 10 m of water. During the time of the experiment, there were two stormy days with breaking waves and nearby high surf. It was observed that pulse-to-pulse variations (over seconds) in travel times, over a range of frequencies, increased dramatically from those observed on quiet days. Average travel times also increased by about 3%. Dispersion was also observed. The distance between the source and the receiver towers was approximately 60 m. By assuming that bubbles were either generated by breaking waves and advected down ward and/or generated by surf and advected outward, these results are explained. Estimates of the average bubble density and bubble-density variations are made.