3aUW1. Reproducibility of low-frequency shallow-water acoustic experimental data.

Session: Wednesday Morning, May 15

Time: 8:20

Author: Richard B. Evans
Location: SAIC, 21 Montauk Ave., Ste. 201, New London, CT 06320
Author: W. M. Carey
Location: ARPA, Arlington, VA 22203


Transmission loss measurements were conducted in September 1993 on the continental shelf off New Jersey. Low-frequency continous-wave data were recorded on a vertical line receiving array in approximately 73 m of water. The geometry of these measurements replicates the geometry of experimental measurements conducted during October 1988 at the same site and under similar downward refracting conditions. The sets of frequencies transmitted during the two experiments were different, but covered the region less than 1 kHz. Acoustic surveys and geophysical data obtained in 1988 provided detailed characterizations of the seabed. The bottom characterization is assumed to be time invariant, except for the contribution of the pore fluid to the uppermost layers of the sediment. Consequently, the characterization of the seabed should be valid when the bottom waters are similar. The coincidence of the two sets of experimental data and a valid geoacoustic model provide the opportunity to test the reproducibility of these results. The bottom characterizations based on two sets of acoustic data are compared with expectations based on profiles derived from geophysical data.

from ASA 131st Meeting, Indianapolis, May 1996