Li Zhang
Ctr. for Marine Sci., Univ. of Southern Mississippi, Stennis Space Center, MS 39529
Ralph Goodman
Penn State Univ., State College, PA 16804
Steve Stanic
Naval Res. Lab., Stennis Space Center, MS 39529
Mire and Stanic (preceding abstract) have observed significant pulse to pulse fluctuations in high-frequency seafloor backscattering measurements in which the sound sources and receivers were mounted on a tower that stood on the seafloor in a shallow-water environment (about 30 m). This paper presents the hypothesis that temperature fluctuations that are associated with turbulence can account for the acoustic variability. The model is based on a random distribution of fixed discrete scatters on the surface of the seafloor. Computations that sum the arrivals of scattered CW pulses for a range of changes in travel times that are due to varieties in the average temperature along the paths reveal fluctuations similar to Mire and Stanic's observations for a range of tens of meters, temperatures changes as small as a tenth of a degree Celsius, and frequencies of about 40 kHz and higher. Comparisons between computations and measurement are presented in this paper. [Work supported by NRL/Stennis.]