浅海双跃层脉冲声传播

利用在东海测量的双跃层声速剖面和修改的单跃层声速剖面,数值模拟了2种跃层条件下不同收发深度声脉冲传播的波形。模拟结果表明,当声源或接收器位于上混合层时,信号波形在2种条件下都出现梳状多途结构。当声源和接收器都位于下混合层时,信号波形在2种条件下均相似。当声源位于中间均匀层时,信号波形在除上混合层以外的4层都有显著差异。用简正波的深度-简正波号域的幅度和相应的群速度解释了双跃层和单跃层声速剖面条件下信号波形特点以及异同的原因。

Acoustic Pulse Propagation in Shallow Water With Double Thermocline

The double thermocline sound speed profile(SSP) measured in the East China Sea and its modified single thermocline SSP were used to numericaly simulate the waveforms of acoustic pulse propagation with different sound source and receiver depths and under the two thermocline conditions.It is shown from the simulated results that when the sound source or receiver is located in the upper mixed layer,the received signal waveforms under the two conditions all show a comb-shaped multipath structure;when the sound source and receiver are located in the lower mixed layer,the received signal wave forms under the two conditions are similar to each other;and when the sound source is located in the intermediate homogeneous layer,the received signal wave forms in the four layers other than the upper mixed layer are quite different from each other.The modal amplitudes in the depth and mode-number space and their associated group velocities are used to explain the signal waveform characteristics under the two conditions and the reason for their similarities and differences.