Acoustic characteristics of seawater in the area of the coastal discharge front off the Guinean shore

Pulgakov, N. P.; Ломакин, П. Д.

doi:10.1007/bf02197512

Cited by 3 publications

(2 citation statements)

References 1 publication

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“…They distinguished the haline channel from the hydrostatic channel, which is more affected by hydrostatic pressure than by either temperature or salinity. 14,15 The cause of channel formation, salinity, or pressure can easily be established for tropical oceans where the physical a) Author to whom correspondence should be addressed. Electronic mail: paeng@jejunu.ac.kr structure of the surface layer is relatively stable and contribution of temperature is marginal.…”

Section: Introductionmentioning

confidence: 99%

Low-salinity-induced surface sound channel in the western sea of Jeju Island during summer

Kim

Paeng

et al. 2015

The Journal of the Acoustical Society of America

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Surface salinity in the western sea of Jeju Island in Korea becomes low due to the inflow of the Chinese coastal waters during summer. One of the characteristics of low salinity water is the formation of a surface sound channel (SSC) due to the decrease in sound speed by salinity. However, a quantitative analysis between low salinity water and SSC has not been fully investigated yet. In this paper, a temperature-salinity (T-S) gradient diagram is introduced in order to assess SSC formation and its acoustic characteristics are also investigated through a case study of low salinity waters. Maximum angles of limiting rays were less than 4.6° and low frequency cutoffs were higher than 2.0 kHz for the SSCs formed in low salinity water. When the salinity gradients were large (>0.5 psu/m), a SSC was formed more efficiently than other cases whose salinity gradients were small. On the other hand, a SSC was not formed in spite of highly positive salinity gradients when the amount of temperature gradients was negatively high enough (<-0.5 °C/m). However, the acoustic energy transfer in the surface ducts was dependent on frequency and position of source.

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Section: Introductionmentioning

confidence: 99%

Low-salinity-induced surface sound channel in the western sea of Jeju Island during summer

Kim

Paeng

et al. 2015

The Journal of the Acoustical Society of America

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“…This area contains a strong freshening of oceanic waters by continental discharge and rainfall. As a result, these studies were able to distinguish the "haline duct" from the hydrostatic duct [11,12]. Since the mixed layer in the tropical ocean is relatively stable, temperature contributes little, and as such, the formation of the haline duct was due to a sharp change in salinity.…”

Section: Introductionmentioning

confidence: 91%

Analysis of Surface Sound Duct in the Northern Shelf of the South China Sea

Piao

Zhou

et al. 2018

Shock and Vibration

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The northern shelf of the South China Sea (NSSCS) is characterized by surface low-salinity water due to discharge from the Pearl River. In such an environment, the surface sound duct (SSD) is the most important duct for near-surface sonar applications. Nevertheless, the mechanism of SSD formation is very complicated and is influenced by salinity, temperature at the air-sea interface, and various additional marine phenomena. In this study, an 8-year conductivity-temperature-depth (CTD) profile of the NSSCS was used to analyze the SSD formation. An advanced diagrammatic method is proposed to provide a quantitative analysis of the contribution of salinity, temperature, and hydrostatic pressure on SSD formation. Large salinity gradient (0.25 psu/m) was shown to play a crucial role in SSD formation when a mixed layer exists. As representative examples, the sea under cold surges, typhoon genesis, and low-salinity lenses were studied. Conversely, the absence of SSDs in low-salinity water was also observed in upwelling regions. This study further showed that highly negative temperature gradients affect SSD formation even in low-salinity water. Furthermore, although the duct depth of a low-salinity SSD is usually less than 10 meters, it still can serve as an effective duct for acoustic propagation.

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Simulation Study on Sound Propagation Characteristics of Low-Salinity Lens Outside the Pearl River Estuary

Huang,

Deng,

2024

2024 OES China Ocean Acoustics (COA)

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Acoustic characteristics of seawater in the area of the coastal discharge front off the Guinean shore

Cited by 3 publications

References 1 publication

Low-salinity-induced surface sound channel in the western sea of Jeju Island during summer

Low-salinity-induced surface sound channel in the western sea of Jeju Island during summer

Analysis of Surface Sound Duct in the Northern Shelf of the South China Sea

Simulation Study on Sound Propagation Characteristics of Low-Salinity Lens Outside the Pearl River Estuary

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