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.]