Analysis of Mesoscale Eddy Effects on Sound Wave Propagation Using the Bellhop Model

Abstract This study focuses on a mesoscale eddy in the South China Sea, analyzing its intensity, size, and temperature-salinity structure using reanalysis data. Two sets of experiments were conducted using the Bellhop acoustic model to simulate the propagation of sound waves from inside the eddy to the outside and vice versa. In each set of experiments, control experiments were also performed to investigate the impact of the mesoscale eddy on sound propagation. The results indicate that when the sound source is located at 50 m below the surface and propagates outward from the eddy center, the warm eddy causes an expansion of the surface channel radius by 22 km. For sound sources at 150 m and 250 m below the surface, the warm eddy weakens the acoustic energy, causing the convergence zone to shift forward, with the depth of the convergence zone increasing as the propagation distance increases. When the sound source is located at 50 m below the surface and propagates inward from outside the eddy, the warm eddy causes the surface channel to disappear. For sound sources at 150 m and 250 m below the surface, the warm eddy slightly shifts the convergence zone forward, with a significant decrease in the depth of the convergence zone. Finally, error comparison experiments were conducted to validate the rationality and rigor of the experimental setup.