Effects of Dipole Eddies on Acoustic Propagation in the Northeastern South China Sea

Mesoscale eddies can greatly influence underwater acoustic propagation, which holds substantial academic and practical importance. The impacts of individual cyclonic eddies (CEs) or anticyclonic eddies (AEs) on acoustic propagation have been reported in the global ocean, but the influences of dipole...

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Main Authors: Lu Lu, Feng Nan, Anqi Xu, Xiangqian Liang, Fei Yu
Format: Article
Language:English
Published: American Association for the Advancement of Science (AAAS) 2025-01-01
Series:Ocean-Land-Atmosphere Research
Online Access:https://spj.science.org/doi/10.34133/olar.0056
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author Lu Lu
Feng Nan
Anqi Xu
Xiangqian Liang
Fei Yu
author_facet Lu Lu
Feng Nan
Anqi Xu
Xiangqian Liang
Fei Yu
author_sort Lu Lu
collection DOAJ
description Mesoscale eddies can greatly influence underwater acoustic propagation, which holds substantial academic and practical importance. The impacts of individual cyclonic eddies (CEs) or anticyclonic eddies (AEs) on acoustic propagation have been reported in the global ocean, but the influences of dipole eddies remain unclear. Dipole eddies, with warm-core AE shedding from the Kuroshio loop and cold-core CE on the northeastern side, frequently form in the northeastern South China Sea (SCS). In this study, the effects of 3 pairs of dipole eddies in the northeastern SCS on acoustic propagation were examined via satellite altimeter data, reanalysis data, and a ray tracing model. In general, the AEs were larger and stronger than the CEs. The downwelling in the AEs caused positive sound-speed anomalies, whereas the upwelling in the CEs induced negative sound-speed anomalies. Using the Bellhop ray tracing model, we simulated 5 scenarios of acoustic propagation across dipole eddies by varying the sound source locations and sound propagation paths. The special hydrological and sound-speed structure of dipole eddies resulted in notable variations in the convergence zone and acoustic transmission loss in different scenarios, which were markedly different from those of a single eddy. The findings of this study will contribute to underwater acoustic communication, remote detection, reconnaissance, and counterreconnaissance in the SCS.
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institution Kabale University
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language English
publishDate 2025-01-01
publisher American Association for the Advancement of Science (AAAS)
record_format Article
series Ocean-Land-Atmosphere Research
spelling doaj-art-22c13215c8b34a6cbf4397d6f7e62c8b2025-08-20T03:48:27ZengAmerican Association for the Advancement of Science (AAAS)Ocean-Land-Atmosphere Research2771-03782025-01-01410.34133/olar.0056Effects of Dipole Eddies on Acoustic Propagation in the Northeastern South China SeaLu Lu0Feng Nan1Anqi Xu2Xiangqian Liang3Fei Yu4Key Laboratory of Ocean Observation and Forecasting and Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.Key Laboratory of Ocean Observation and Forecasting and Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.Key Laboratory of Ocean Observation and Forecasting and Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.School of Mathematics, Shandong University of Science and Technology, Qingdao, China.Key Laboratory of Ocean Observation and Forecasting and Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.Mesoscale eddies can greatly influence underwater acoustic propagation, which holds substantial academic and practical importance. The impacts of individual cyclonic eddies (CEs) or anticyclonic eddies (AEs) on acoustic propagation have been reported in the global ocean, but the influences of dipole eddies remain unclear. Dipole eddies, with warm-core AE shedding from the Kuroshio loop and cold-core CE on the northeastern side, frequently form in the northeastern South China Sea (SCS). In this study, the effects of 3 pairs of dipole eddies in the northeastern SCS on acoustic propagation were examined via satellite altimeter data, reanalysis data, and a ray tracing model. In general, the AEs were larger and stronger than the CEs. The downwelling in the AEs caused positive sound-speed anomalies, whereas the upwelling in the CEs induced negative sound-speed anomalies. Using the Bellhop ray tracing model, we simulated 5 scenarios of acoustic propagation across dipole eddies by varying the sound source locations and sound propagation paths. The special hydrological and sound-speed structure of dipole eddies resulted in notable variations in the convergence zone and acoustic transmission loss in different scenarios, which were markedly different from those of a single eddy. The findings of this study will contribute to underwater acoustic communication, remote detection, reconnaissance, and counterreconnaissance in the SCS.https://spj.science.org/doi/10.34133/olar.0056
spellingShingle Lu Lu
Feng Nan
Anqi Xu
Xiangqian Liang
Fei Yu
Effects of Dipole Eddies on Acoustic Propagation in the Northeastern South China Sea
Ocean-Land-Atmosphere Research
title Effects of Dipole Eddies on Acoustic Propagation in the Northeastern South China Sea
title_full Effects of Dipole Eddies on Acoustic Propagation in the Northeastern South China Sea
title_fullStr Effects of Dipole Eddies on Acoustic Propagation in the Northeastern South China Sea
title_full_unstemmed Effects of Dipole Eddies on Acoustic Propagation in the Northeastern South China Sea
title_short Effects of Dipole Eddies on Acoustic Propagation in the Northeastern South China Sea
title_sort effects of dipole eddies on acoustic propagation in the northeastern south china sea
url https://spj.science.org/doi/10.34133/olar.0056
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