ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

2aUW8. The effects of a thin slow sediment layer on shallow water acoustic field.

E. C. Shang

Y. Y. Wang

CIRES, Univ. of Colorado/NOAA/Environmental Tech. Lab., Boulder, CO 80303

The seabottom often has a thin layer on its top and the sound speed in this thin layer is less than in water. It has been found that this thin layer can significantly effect the acoustic field in water column. First, it changes the bottom reflection character, and, on the other hand, it changes the modal wave-number difference: D[sub mn]=2(pi)(k[sub m]-k[sub n])[sup -1]. Those two factors determine the basic features of the acoustic field---the modal interference pattern and the modal attenuation rate. Based upon the sensitivity analysis, bottom parameter estimation scheme is proposed.