This work was supported by the Office of Naval Research Ocean Acoustics Program.
The Journal of the Acoustical Society of America
Underwater acoustics, Noise, Acoustical engineering
Ambient ocean noise is processed with a vertical line array to reveal coherent time-separated arrivals suggesting the presence of head wave multipath propagation. Head waves, which are critically propagating water waves created by seabed waves traveling parallel to the water-sediment interface, can propagate faster than water-only waves. Such eigenrays are much weaker than water-only eigenrays, and are often completely overshadowed by them. Surface-generated noise is different whereby it amplifies the coherence between head waves and critically propagating water-only waves, which is measured by cross-correlating critically steered beams. This phenomenon is demonstrated both experimentally and with a full wave simulation.
Gebbie, J., & Siderius, M. (2016). Head wave correlations in ambient noise. The Journal of the Acoustical Society of America, 140(1), EL62-EL66. http://doi.org/10.1121/1.4954897