Edward R. Levine
Richard R. Shell
Michael R. Medeiros
Code 8212, Naval Undersea Warfare Ctr., Division Newport, Newport, RI 02841
High-frequency environmental acoustics studies were conducted during July 1993, on the continental shelf edge east of New Jersey. Internal solitons previously observed in this region near the shelf/slope front propagate in packets, usually in the summer seasonal thermocline, and have been associated with anomalous low frequency sound propagation. Acoustic pings were collected using a towed sled instrumented with sonar arrays. Synoptic measurements to characterize the solitons including sound velocity profiles sampled every 10 min over a tidal cycle, and moored data including current, temperature, and conductivity. Acoustic measurements were taken during sled tows parallel to the bottom bathymetry, normal to the propagation direction, over a region determined from bottom cores to be nearly homogeneous fine sand. Measurements were taken using the sled as a source for backscatter measurements, and also using moored acoustic sources and the sled based transducers as receivers. The observed solitons had amplitudes of approximately 10 m and periods of several minutes. The backscatter variability during soliton events was observed to approximately 10--20 dB, and will be compared to modeled predictions based on environmental data.