The preliminary study on fluctuation of ocean sound field

Abstract

The ocean environmental variation causes the amplitude and phase fluctuations of acoustic signals that travel in the ocean acoustic waveguide. Sound propagation fluctuation is studied based on the deep water fixed-point sound propagation experiment data acquired in the northern South China Sea in 2016. In this experiment, two sets of submerged buoy systems, which integrate the emission and receiving of sound wave, have continuously and steadily worked as long as three months. Considering the Doppler frequency shift, the amplitude and phase of acoustic signals are calculated after matched filtering. The sound intensity scintillation index computed for the entire record is 0.8, which is less than the saturation value of one. In contrast, the scintillation index computed for the 2001 ASIAEX South China Sea Experiment is 2.6 and 1.7. The ocean environmental variation and its relation with sound propagation fluctuation are analyzed.