ASA 126th Meeting Denver 1993 October 4-8

1pUW6. Comparison of UMPE/PEREV bistatic reverberation predictions with observations in the ARSRP Natural Lab.

Kevin B. Smith

Marine Phys. Lab., Scripps Inst. of Oceanogr., Mail Code 0704, La Jolla, CA 92093-0704

Frederick D. Tappert

University of Miami, Miami, FL

William S. Hodgkiss

Scripps Inst. of Oceanogr., La Jolla, CA

During the summer of 1993 acoustic experiment sponsored by the ONR Acoustic Reverberation Special Research Program, bistatic bottom reverberation measurements were made within the ARSRP Natural Laboratory near the mid-Atlantic ridge. Employing a version of the University of Miami Parabolic Equation (UMPE) model [MPL Tech. Memo, 432 (1993)] incorporating Tappert's PE Reverberation (PEREV) model, calculations of monostatic and bistatic reverberation within the Natural Laboratory have been made. The UMPE/PEREV model predicts a strong correlation between areas of high reverberation and high bottom ensonification. Furthermore, the wave scattering strength predicted by the PEREV model is shown to depend on the bottom roughness spectrum evaluated at the Bragg wave number 2k[sub 0] sin((phi)[sub s]/2) where (phi)[sub s] is the azimuthal scattering angle. Due to the typical power-law form of the roughness spectrum, this suggests that the wave scattering strength is enhanced in the direction of forward scatter. These predictions will be compared to the observations and the validity of hypotheses will be addressed. [Work supported by ONR, Code 1125OA.]