Effects of Shallow Water Bottom Interface Roughness and Volume Fluctuations on Broadband Pulse Resolution

This is a NAVAL POSTGRADUATE SCHOOL MONTEREY CA report procured by the Pentagon and made available for public release. It has been reproduced in the best form available to the Pentagon. It is not spiral-bound, but rather assembled with Velobinding in a soft, white linen cover. The Storming Media report number is A734313. The abstract provided by the Pentagon follows: Typical acoustic propagation in shallow water environments is dominated by bottom-interacting paths. The effects of rough bottom interfaces and sediment volume fluctuations are investigated using model simulations. A numerical study of low-frequency (approx. 2OO Hz) broadband pulse propagation is presented and several characterizations of bottom factors are examined. In particular, the variations of the interface rms roughness and a volume fluctuation strength constant on the time resolution of the broadband pulse are investigated. It is shown that interface roughness is the dominant factor in the degradation of pulse resolution.