ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06
2pAO7. Depth-dependent gas fractions in acoustic models of marine
sediments.
Frank A. Boyle
Nicholas P. Chotiros
Appl. Res. Labs., Univ. of Texas, P.O. Box 8029, Austin, TX 78713-8029
Models have recently been developed for acoustic scattering from trapped
gas bubbles in sandy and silty marine sediments [F. A. Boyle and N. P.
Chotiros, 3219 (A) (1994) and F. A. Boyle and N. P. Chotiros,
1766 (A) (1993)]. These preliminary models may be somewhat limited in
applicability due to an assumption that the bubbles are distributed
homogeneously throughout the half-space below the sediment interface.
Observations suggest that actual sediments are horizontally stratified, and
that gas fractions have strong depth dependence. The models have therefore been
modified to allow specification of a depth-dependent gas fraction. Studies
suggest that the backscattering strength is significantly affected, with
considerable influence on its grazing angle dependence. [Work supported by
Naval Research Laboratory, Stennis Space Center under the MCM Tactical
Environmental Data System (MTEDS) project.]