Refined analysis of spatial and temporal variations of acoustic field characteristics in the Eastern Luzon strait sea area

Abstract The marine environment is substantially capable of affecting sound propagation, with sound field characteristics that vary across seasons and marine regions. Existing studies on sound field characterization are mostly based on two-dimensional acoustic propagation models, which are not refined enough to accurately grasp the spatial and temporal characteristics of a certain sea area. This paper performs a 3D sound propagation simulation experiment designed for the sea area east of Luzon Strait based on reanalysed marine environment data and the Bellhop 3D model. The experiment was conducted under different seasons and with varying depths of sound sources, and its findings were analysed in detail with regard to various acoustic characteristics, such as propagation loss, convergence zone parameters, and others. The results show that: (1) For different source depths, the sound propagation loss decreases with an increase in source depth; For different propagation directions, the propagation loss in the north-south direction is smaller than that in the east-west direction. (2) For different seasons, the propagation loss is mainly observed within the first 200 meters of depth. (3) The distance to the first convergence zone in spring and winter is greater than that in summer and fall. In comparison to other seasons, the distance to the first convergence zone in summer exhibits the least change with propagation direction. The distance to the first convergence zone decreases with an increase in the sound source depth.