Sound intensity fluctuations caused by internal solitary wave train in the South China Sea

Abstract Dynamic internal solitary wave (ISW) can cause significant underwater sound fluctuations. In this paper, the periodic characteristics of sound intensity fluctuations and related physical mechanisms are investigated in the scenario that an ISW train passing through the acoustic path from source to receivers. From simulation results and experimental data, it is shown that the sound intensity fluctuates quasi-periodically, and the predominant fluctuation frequency is associated with modal interference and modal intensity. The initial mode coefficients at the source and the mode coupling are responsible for the fluctuations of modal intensities, and one of the predominant fluctuation periods is the same as that of the ISWs.