Effect of sound speed profile on the structure of acoustic pulse and the convergence zone in deep water

Abstract

Through the experimental data collected in different seasons with the propagation conditions change in the East Indian Ocean (EIO) and the South China Sea (SCS), we observe that the structure of the sound speed profiles (SSPs) in these two seas area is very different and has a significant impact on the CZs and time arrival structure of acoustic pulses. In the EIO environment, sound energy transmitting along the sound channel axis (SCA) is relatively large, and the corresponding signals arrive first, whereas signals propagating off the SCA arrive late, which is totally different with the characteristics of the waveform in the SCS. At the same time, the range of the first CZ in the EIO is 7–8 km farther than that in the SCS, and the width of the CZs in the EIO is about 2–3 km narrower when the water depths in the two experimental areas are similar. Combined with the theoretical model, the influence mechanism of SSP on the time arrival structure and CZ propagation are theoretically analyzed, which well explains the phenomenon observed in the two experiments. The results can provide a reference for the application of communication sonar in the deep-sea remote environment.