Acoustics Division, Naval Research Laboratory, Washington, DC 20375, USA.
J Acoust Soc Am. 2013 Apr;133(4):1981-6. doi: 10.1121/1.4792141.
Significant acoustic travel-time variability and frequency shifts of acoustic intensity level curves in broadband signal spectrograms were measured in the East China Sea during the summer of 2008. The broadband pulses (270-330 Hz) were transmitted from a fixed source and received at a bottomed horizontal array, located at the 33 km range. The acoustic intensity level curves of the received signals indicate regular frequency shifts that are well correlated with the measured internal tides. Similarly, regular travel-time shifts of the acoustic mode arrivals correlate well with the barotropic tides and can be explained by tidal currents along the acoustic propagation track. These observations indicate the potential of monitoring internal tides and tidal currents using low-frequency acoustic signals propagating at long ranges.
2008 年夏季在中国东海的测量中，发现宽带信号声谱图中的声传播时间和声强级曲线出现了显著的频移和变化。宽带脉冲（270-330Hz）由固定声源发射，在 33 公里处的底部水平基阵接收。接收信号的声强级曲线显示出规则的频移，与测量到的内潮非常相关。同样，声模态到达的规则传播时间偏移与潮汐相关，这可以通过声传播路径上的潮流来解释。这些观测表明，利用低频声信号在长距离传播来监测内潮和潮流是具有潜力的。
