Analysis of Acoustic Propagation Characteristics in the Okinawa Sea Region Beneath Fluctuating Sea Surfaces

The strong winds and pressure changes induced by typhoons cause significant fluctuations and anomalies in sea surface levels. This study utilizes data from the ERA5 reanalysis database, focusing on the fluctuating sea surface conditions during the passage of Typhoon “Khanun.” Five hours of data were randomly selected for analysis. Using the BELLHOP3D model, which accounts for horizontal refraction effects, acoustic propagation characteristics under different sea surface conditions were simulated. The average results from the five simulations were analyzed. The findings indicate that fluctuating sea surfaces have a substantial impact on acoustic propagation loss. Compared to calm conditions, the influence of typhoons on the sea surface significantly intensifies energy attenuation during acoustic propagation. As the propagation distance increases, the sound transmission loss caused by the typhoon-affected sea surface becomes more pronounced. However, with increasing propagation depth, the loss effect induced by surface fluctuations gradually diminishes.