Analyzing sound speed fluctuations in shallow water from group-velocity versus phase-velocity data representation

Philippe Roux (1) , William A. Kuperman (2) , Bruce D Cornuelle (2) , Florian Aulanier (3) , William S. Hodgkiss (2) , Hee Chun Song (2)

1 Ondes et Structures
2 Marine Physical Laboratory of the Scripps Institution of Oceanography
3 GIPSA-SIGMAPHY - GIPSA - Signal Images Physique

Data collected over more than eight consecutive hours between two source-receiver arrays in a shallow water environment are analyzed through the physics of the waveguide invariant. In particular, the use of vertical arrays on both the source and receiver sides provides source and receiver angles in addition to travel-times associated with a set of eigenray paths in the waveguide. From the travel-times and the source-receiver angles, the eigenrays are projected into a group-velocity versus phase-velocity (Vg-Vp) plot for each acquisition. The time evolution of the Vg-Vp representation over the 8.5-h long experiment is discussed. Group speed fluctuations observed for a set of eigenrays with turning points at different depths in the water column are compared to the Brunt-Väisälä frequency.

Mots clés: acoustic arrays; acoustic wave velocity; underwater sound

Domaines: Océanographie

Philippe Roux, William A. Kuperman, Bruce D Cornuelle, Florian Aulanier, William S. Hodgkiss, et al.. Analyzing sound speed fluctuations in shallow water from group-velocity versus phase-velocity data representation. Journal of the Acoustical Society of America, 2013, 133 (4), pp.1945-1952. ⟨10.1121/1.4792354⟩. ⟨hal-00841130⟩