ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

1pAO8. Modeling of high-frequency pulse propagation in the Yellow Sea with internal wave and rough boundary scattering.

X. Tang

F. D. Tappert

H. A. DeFerrari

Appl. Marine Phys., Univ. Miami, RSMAS, 4600 Rickenbacker Cswy., Miami, FL 33149

The broadband UMPE ocean acoustic model is used to simulate high-frequency (3 kHz) pulse propagation in the Yellow Sea. Internal waves are known to be active in the summer, and are modeled with a broad spectrum of excitation. Due to the existence of a strong thermocline in the upper part of the water column, the signal at a distant (5 km) receiver exhibits a characteristic multipath structure according to the geometric configuration of source and receiver---whether above and/or below the thermocline. When internal wave fluctuations are introduced, the simulated waveforms are altered and agree better with the experimental observation made in the summer of 1993 [R. Zhang, J. Acoust. Soc. Am. 97, 3368(A) (1995)]. Both rough surface and rough water--sediment interface scattering are included in the model in the belief that their effects cannot, in general, be separated from the volume scattering by internal waves. A 10-h time history of repeated pulse transmissions simulated in accordance with the recorded ocean temperature fluctuation is computed and displayed, and illustates the temporal instability of shallow-water propagation. [Work supported by ONR.]