Studying the influence of cold-core mesoscale ocean eddies on sound propagation based on the parabolic equation method

Abstract

Mesoscale vorticity is an important factor that affects the non-uniform horizontal and vertical distribution of hydrologic elements in the ocean. In this paper, temperature and salinity data from measured mesoscale cold-core eddies during a voyage within a certain sea area are studied, and a synchronous sound field test was conducted on the mesoscale vorticity. Based on the temperature and salinity data, the parabolic equation (PE) method was selected to predict the acoustic field, and the results were compared with the measured propagation loss data of the acoustic field to verify the accuracy and effectiveness of the PE model. The underwater sound propagation characteristics in the mesoscale cold-core eddy environment were then analyzed using the temperature and salinity data retrieved from the voyage. It was found that the convergence area of the acoustic field gradually dispersed with an increase in the depth of the sound source. In a mesoscale eddy environment, when sound waves propagate from inside to outside the eddy, the presence of a cold-core eddy causes the convergence area to shift toward the edge of the eddy, and the deviation gradually decreases with an increase in the depth of the sound source.