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

2aAO10. Forward-scattering simulations through ocean-ridge hydrothermal-vent diffusive layer turbulence: Feasibility of vent monitoring.

T. F. Duda

Woods Hole Oceanogr. Inst., Bigelow 2, Woods Hole, MA 02543

D. A. Trivett

Dalhousie Univ., Halifax, NS B3H 4J1, Canada

Temperature and velocity fluctuations in a bottom boundary layer down-current of Juan de Fuca Ridge hydrothermal sites were monitored in 1990 from tripods. The diffuse flow from relatively cool vents remains near the bottom, and acoustic refractive index fluctuations decay away slowly. Rytov theory-based forward-scattering simulations through structures consistent with the observations are used to verify the validity of Rytov theory, compare the usefulness of various propagation path lengths and frequencies on monitoring, and evaluate the ability of acoustic phase and amplitude recordings to monitor desired vent parameters. The Rytov theory is valid for some ranges and frequencies, but issues such as turbulence homogeneity, energy dissipation rate, boundary-layer depth, beam patterns, and sensor motion would have strong effects on the measurements.