The viability of acoustic tomography in monitoring the circulation of Monterey Bay

Alternate Titles

• NPS-62-90-003.

Description

This report presents the results of a fifteen month study on the viability of acoustic tomography in monitoring the circulation of Monterey Bay, California. The basis for ocean acoustic tomography is the measurement of travel times of coded acoustic signals between the transceivers. The sound speed field and current structure can be inferred from the fluctuations in travel times. However, the extreme bathymetry of the Monterey Submarine Canyon complicates the acoustic transmissions in the Bay. The study consisted of an experiment and a computer modeling effort. The experiment consisted of transmitting tomography signals in the Bay for four days. The signals were received with a sonobuoy- based telemetry system. The experimental effort showed multipath arrivals that were stable and resolvable. The modeling effort involved the use of 2-D and 3-D ray tracing computer programs. The programs had difficulty in modeling the effects of Monterey Bay's extreme bathymetry making the multipath identification challenging. Progress is expected with the augmentation of the ray tracing programs with Gaussian beam and time front postprocessors. Acoustic tomography, Underwater acoustics.

Subjects