Observation of a mesoscale warm eddy impacts acoustic propagation in the slope of the South China Sea

Acoustic rays are modified while propagating through oceanic eddies. However, due to the lack of field synchronous observation, impact mesoscale eddy on acoustic propagation is less clarified. To address issue, an eddy-acoustic observation (EASO) experiment for a warm was carried out in slope South China Sea (SCS) October, 2021. During experiment, total 105 conductivity-temperature-depth (CTD) stations, as well zonal survey line center eddy, were obtained. The vertical structures temperature and salinity indicate that surface-intensified with cores confined within depths from 70 m 200 10 m, respectively. shows two obvious convergency zones (CZs) at about 39 km 92 eastern half line, one (CZ) 25 western line. By comparing none circumstance, respective impacts topography quantitatively analyzed ray-tracing model. results shortens horizontal span CZ by 11.4 km, lengthens it 1.7 km. Additionally, shallows depth broadens width 32 1.4 anisotropy 3D sound fields jointly influenced local show distance differences first CZs different directions can be long 31