ASA 124th Meeting New Orleans 1992 October

2pAO15. On ray/mode approaches to the broadband shallow water tomography problem in the coastal Barents Sea acoustic test experiments.

A. Yu. Shmelerv

A. R. Kozel

A. A. Migulin

Inst. of General Phys., Moscow, Russia

James F. Lynch

Woods Hole Oceanogr. Inst., Woods Hole, MA 02543

In shallow water tomography, use of acoustic sources with 100-Hz bandwidth causes great problems with resolution and identification of the arrivals due to diffraction and dispersion at low frequency. These problems can be resolved in terms of ray theory with beam displacement and mode theory in different ways. This paper discusses the results of numerical calculations of ray/mode resolution and estimates dispersion in shallow water waveguides. Numerical calculations were carried out for an ideal model waveguide with linear and isovelocity sound-speed profiles as well as for the coastal Barents Sea acoustic test experiment conditions. The experiment took place during October 1990 in the coastal region of the Barents Sea (to be published in Sov. Phys. Acoust. in 1992). Presented here are also plans for future coastal Barents tomography experiments.