Ocean ambient noises modulated by internal solitary waves

Internal solitary waves greatly impact the ocean environment as well as the underwater acoustic propagation. Most observed internal solitary waves are categorized as mode-1 waves. They could generate the surface wave breaking in the convergence zone and produce ocean noises. These ocean noises would be enhanced in the convergence zone and reduced in the divergence zone due to rough and smooth sea surface conditions, respectively. This study observed the sound source from surface wave breaking affected the high sonic bands between 100 Hz and 10K Hz. The maximum noise was around 10 dB increment at 1.5K Hz and coincided with the maximum convergence (downwelling), which agrees well with the theory. Strong horizontal currents induced by internal solitary waves would produce self-noise in the infra and low sonic bands below 300 Hz.