scholarly journals Sound Scattering from Microbubble Distributions Near the Sea Surface

1993 ◽  
pp. 25-43 ◽  
Author(s):  
William M. Carey ◽  
Ronald A. Roy
Keyword(s):  
Sea Surface ◽  
Sound Scattering

scholarly journals Sound Scattering Layers Within and Beyond the Seychelles-Chagos Thermocline Ridge in the Southwest Indian Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Myounghee Kang ◽  
Jung-Hoon Kang ◽  
Minju Kim ◽  
SungHyun Nam ◽  
Yeon Choi ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Unique Feature ◽  
Acoustic Scattering ◽  
Sea Surface ◽  
Distribution Dynamics ◽  
Sound Scattering ◽  
Southwest Indian Ocean ◽  
Environmental Properties ◽  
Distinct Features ◽  
Global Oceans

In global oceans, ubiquitous and persistent sound scattering layers (SL) are frequently detected with echosounders. The southwest Indian Ocean has a unique feature, a region of significant upwelling known as the Seychelles-Chagos Thermocline Ridge (SCTR), which affects sea surface temperature and marine ecosystems. Despite their importance, sound SL within and beyond the SCTR are poorly understood. This study aimed to compare the characteristics of the sound SL within and beyond the SCTR in connection with environmental properties, and dominant zooplankton. To this end, the region north of the 12°S latitude in the survey area was defined as SCTR, and the region south of 12°S was defined as non-SCTR. The results indicated contrasting oceanographic properties based on the depth layers between SCTR and non-SCTR regions. Distribution dynamics of the sound SL differed between the two regions. In particular, the diel vertical migration pattern, acoustic scattering values, metrics, and positional properties of acoustic scatterers showed two distinct features. In addition, the density of zooplankton sampled was higher in SCTR than in the non-SCTR region. This is the first study to present bioacoustic and hydrographic water properties within and beyond the SCTR in the southwest Indian Ocean.

Sound scattering by an air bubble near a plane sea surface

1997 ◽  
Vol 102 (2) ◽  
pp. 798-805 ◽  
Author(s):  
Zhen Ye ◽  
Christopher Feuillade
Keyword(s):  
Sea Surface ◽  
Sound Scattering ◽  
Air Bubble

Sound scattering by bubble clouds near the sea surface

2000 ◽  
Vol 107 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Guillermo C. Gaunaurd ◽  
Hanson Huang
Keyword(s):  
Sea Surface ◽  
Sound Scattering ◽  
Bubble Clouds

scholarly journals Sound scattering by a single and by a cloud of air bubbles near the sea surface

1994 ◽  
Vol 96 (5) ◽  
pp. 3231-3231
Author(s):  
G. C. Gaunaurd ◽  
H. Huang
Keyword(s):  
Sea Surface ◽  
Air Bubbles ◽  
Sound Scattering

scholarly journals Prediction of Sound Scattering from Deep-Sea Targets Based on Equivalence of Directional Point Sources

2021 ◽  
Vol 11 (11) ◽  
pp. 5160
Author(s):  
Jinpeng Liu ◽  
Zheng Zhu ◽  
Yongqiang Ji ◽  
Ziyang Chen ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Point Source ◽  
Deep Sea ◽  
Free Field ◽  
Acoustic Scattering ◽  
Sea Surface ◽  
Elastic Structure ◽  
Theoretical Modelling ◽  
Sound Scattering ◽  
Scattering Field

A fast prediction method is proposed for calculating the sound scattering of targets in the deep-sea acoustic channel by equating the sound scattering field of a complex elastic target to the acoustic field excited by a directional point source. In deep-sea conditions, the effects of the sea surface on the impedance characteristics of the elastic target surface can be ignored. Through the finite element simulation of the acoustic scattering of the target in the free field, the sound scattering field is equated to the radiation field of a directional point source. Subsequently, the point source is placed in the channel, and the acoustic ray method is used to calculate the distribution of the scattering field. On the basis of theoretical modelling, the method of obtaining the directional point source and the influence of the sea surface on the impedance of the scattering field are analysed. Subsequently, the proposed method is compared with the finite element method in terms of computational efficiency. The result shows that the method considers the multiple complex coupling effects between the elastic structure and marine environment. The influence of the boundary is approximately negligible when the distance from the ocean boundary to the elastic structure is equal to the wavelength. The method only performs finite element coupling calculation in the free field; the amount of mesh size is greatly reduced and the calculation efficiency is significantly improved when compared with the finite element calculation in the entire channel, the. The calculation time in the example can be reduced by more than one order of magnitude. This method organically combines the near-field calculation with acoustic ray theory and it can realise the rapid calculation of the large-scale acoustic scattering field in complex marine environments.

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