Response of sound propagation characteristics to Luzon cold eddy coupled with tide in the Northern South China Sea

Frontiers in Marine Science

Marine Science

Hongli Fu¹  Xuefeng Zhang²  Zhiwen Qian²  Yu Liu² 

[1] Key Laboratory of Marine Environmental Information Technology, National Marine Data and Information Service, Ministry of Natural Resources, Tianjin, China;Marine Science and Technology, Tianjin University, Tianjin, China;

关键词: sound propagation;    eddy;    tide;    numerical simulation;    Northern South China Sea;   

DOI  :  10.3389/fmars.2023.1278333

 received in 2023-08-16, accepted in 2023-10-02,  发布年份 2023

来源: Frontiers

【 摘 要 】

The northern part of the South China Sea is a complex ocean environment with a large range of tidal waves and the stable Luzon cold eddy, which significantly influence the sound propagation characteristics through their impact on sound speed. This study uses a 3D ocean-acoustic framework consisting of MITgcm and BELLHOP ray model to investigate the coupled effects of the Luzon cold eddy and tidal waves. Firstly, the model incorporates tidal assimilation to reconstruct the hydrographic field and compute the sound speed field. Subsequently, the sound propagation in a representative region in the northern South China Sea is simulated to compare the response of sound propagation characteristics to the Luzon cold eddy only, tide only, and the coupled effect of both. The results demonstrate that the cold eddy shifts the location of the convergence zone forward by over 5 km at most. Further, it also makes the acoustic energy focus on the first few arrivals and delays the arrival time of rays by about 0.1 s. The tidal waves intensify these effects, resulting in a further increase of the forward distance of the convergence zone by 2-5 km and a delay in arrival time by 0.02 s. Sound propagation in the coupled influence of these two dynamic processes is exposed to steady perturbations from the cold eddy and spatial-temporal perturbations from tidal waves. The model in this study provides valuable insight for underwater detection and positioning in the realistic ocean environment.

【 授权许可】

Unknown   
Copyright © 2023 Liu, Zhang, Fu and Qian