John L. Spiesberger
Dept. of Meteorol. and the Appl. Res. Lab., 512 Walker Bldg., Penn State Univ., University Park, PA 16802
In the 1980s, the Kaneohe source, on the north shore of Oahu, transmitted sound (133 Hz; 60-ms resolution) from 183-m depth to a U.S. Navy receiver at 3709-km distance near northern California. Despite the fact that sound reflects from the Oahu slope before being trapped in the sound channel, ray theory is shown capable of determining the spatial coordinates of the stable acoustic pulses. Rays that bounce from the bottom are probably chaotic, but the coordinates and travel times of eigenrays are insensitive to initial conditions and ocean fluctuations. The coda of the reception can probably not be explained with a propagation model in which the sound-speed field is smoothed to suppress scales smaller than the mesoscale. Instead, it appears that scattering of sound from smaller scales distributes otherwise axially trapped sound over 1000 m in the vertical, thus limiting the vertical resolution achievable with tomography. [Work supported by Advanced Research Projects Agency and Office of Naval Research.]