Impact of Mesoscale Eddies on Acoustic Propagation Under a Rough Sea Surface

This study examines the combined effects of mesoscale eddies and rough sea surfaces on acoustic propagation in the eastern Arabian Sea and Gulf of Aden during summer mon-soon conditions. Using three-dimensional sound speed fields from CMEMS, sea surface spectra from the SWAN wave model validated by Jason-3 altimetry, and the BELLHOP ray-tracing model, we quantify their synergistic impacts on underwater sound. A Monte Carlo-based dynamic sea surface roughness model is coupled with BELLHOP to analyze multiphysical interactions. Results show that sea surface roughness dominates surface duct propagation, increasing transmission loss by ~20 dB compared to smooth surfaces, while mesoscale eddies deepen the surface duct and broaden convergence zones by up to 5 km. In deeper waters, eddies shift convergence zones and reduce peak sound intensity in the deep sound channel. These findings enhance sonar performance and underwater communication in dynamic, monsoon-influenced marine environments.