The analysis of the depth dependence of ambient noise in the South China Sea

Abstract

A 64-element vertical array was deployed in the South China Sea for ocean ambient noise observation. A rainstorm passed over the area during the experiment, lasting a total of 35 minutes. The differences between the depth distribution and vertical coherence of wind-driven noise and rain noise are compared, and the influence of rainfall rates on them is analyzed. The wind-driven noise intensity decreases with increasing depth, and it is basically consistent with the theoretical results. The depth distribution of rain noise is different from that of wind-driven noise. When the rainfall rate exceeds 48mm/h, the rain noise intensity in the frequency band above 3200Hz increases with increasing depth. Compared with wind-driven noise, the vertical coherence function depth distribution of rain noise is more uniform. The vertical coherence function of rain noise is in good agreement with the simulation results when the noise source directivity index take a larger value.