|Title||Analyzing sound speed fluctuations in shallow water from group-velocity versus phase-velocity data representation|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Roux P, Kuperman WA, Cornuelle BD, Aulanier F, Hodgkiss WS, Song HC|
|Journal||Journal of the Acoustical Society of America|
|Type of Article||Article|
|Keywords||acoustic tomography; frequency; localization; ocean; range; reversal; spectrograms; striations; time sensitivity kernels; wave-guide invariant|
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-Vaisala frequency. (C) 2013 Acoustical Society of America.