The Impact of Mesoscale Eddies on Surface and Subsurface Sound Channels in the Kuroshio Extension

Mesoscale eddies induce significant variations in the temperature and salinity of the upper ocean, thereby exerting a substantial impact on sound propagation. Specifically, they can form or dissipate surface sound channels (SCs) and subsurface sound channels (SSCs). However, the specific impact of mesoscale eddies remains unclear at present. In this paper, META2.0, Argo, and SODA are employed to analyze the sound propagation characteristics of mesoscale eddies in the Kuroshio Extension (KE) by using a composite analysis method and a ray-tracing model. Results demonstrate that cyclonic eddies (CEs) cause the disappearance of the original SCs in winter, while simultaneously generating SSCs. Conversely, anticyclonic eddies (AEs) induce SCs in spring and winter, while in summer they induce SSCs and in autumn create dual-duct sound channels (DCs). This study quantitatively reveals the influence of mesoscale eddies on the genesis and demise of SCs and SSCs, providing technical support for sonar equipment to utilize mesoscale eddies.