Analysis on vertical directivity of shallow‐water ambient noise in South China Sea

2004 ◽  
Vol 115 (5) ◽  
pp. 2508-2508
Author(s):  
Ruey‐Chang Wei ◽  
Hsiang‐Chih Chan ◽  
Po‐Chang Lin
Author(s):  
Shuzhao Li ◽  
Xu Jia ◽  
Zhigang Li ◽  
Jiagang Li

Abstract The northern region of South China Sea is the important strategic region for the offshore oil and gas resources development in China. The main shallow sediment of the region is the cohesive soil with diverse engineering characteristics difficult to be determined. The paper collects the comprehensive geotechnical data obtained from the laboratory test and the in-situ Cone Penetration Test (CPT) for the offshore oil and gas projects in the northern region of South China Sea, and presents the fundamental engineering characteristics of the cohesive soil. Results indicate that the cohesive soil with the low plasticity index and the low clay particle content in shallow water is obviously different from that in deep water in the northern region of South China Sea. The physical properties of the clay soil with the high plasticity index and high clay particle content in the northern deep water region of South China Sea are similar to those found in the Gulf of Mexico and West Africa. Moreover, there are two different deposit modes for the sediment in the northern region of South China Sea, which are the fine-grained and coarse-grained govern deposit modes in deep and shallow water respectively. It is found that the sleeve friction ratio of the cohesive sediment is very low in shallow water. The normalized values of the clay soil in deep water are consistent with those from the Gulf of Mexico and West Africa.


Author(s):  
Ruey-Chang Wei ◽  
J.F. Lynch ◽  
A.E. Newhall ◽  
Hsiang-Chih Chan ◽  
Chih-Sheng Liu ◽  
...  

2017 ◽  
Vol 25 (02) ◽  
pp. 1750034
Author(s):  
Liufang Fu ◽  
Peng Li ◽  
Xinhua Zhang ◽  
Shuqing Ma ◽  
Chengzhi Gao

Ocean ambient noise spectrum is one of the most important characteristics of ambient noise. An ocean vector ambient noise field model was built up based on parabolic equation in this paper. Then the spectra of sound pressure, horizontal particle velocity and vertical particle velocity were calculated applying the model considering noise sources well distributed on the surface with typical summer sound speed profile in South China Sea. The simulation results showed that spectra of sound pressure, horizontal particle velocity and vertical particle velocity were obviously not varied with depth. Then, the simulated results were compared with the experiment results at the receiving depth of a trail in South China Sea in July 2012. Compared with the experimental results, the simulation results are consistent well with the experimental one of sound pressure and horizontal particle velocity in the trend. But the simulation values at low frequency band below 500[Formula: see text]Hz, are not consistent with the experimental one very well, in the band the simulation results are lower than the experimental by about 3–5[Formula: see text]dB. But the simulation result of vertical particle velocity was not consistent with the experimental one, illustrating that the precision of the model might not be enough in the vertical direction.


Author(s):  
E.S. Chertoprud ◽  
H. Gheerardyn ◽  
S. Gómez

The assemblage structure of harpacticoid copepods inhabiting the soft sediments of littoral and sublittoral areas of Cat Ba archipelago (South China Sea) is analysed. Three basic types of harpacticoid taxocenes were observed in the upper sublittoral. Main dominant species of taxocenes were Amphiascoides sp., Stenhelia latioperculata, Paramphiascella sp., Phyllopodopsyllus sp., Tisbe sp.1 and Amphiascoides sp. In addition, the main characteristics of harpacticoid species composition in littoral rock pools are described. A comparative analysis of shallow-water harpacticoid communities from different biotopes of the tropical region is presented, and shows that harpacticoid diversity and abundance are lowest in muddy sediments. Highest diversity and abundance are found in washed sands and silty sands with detritus. In general, the structure of muddy bottom communities is the most homogeneous throughout the tropics. Mangrove forests have no significant influence on harpacticoid taxocene structure. Harpacticoid associations of washed sands and silty sands with detritus demonstrate greater diversity and are region-specific.


2019 ◽  
Vol 148 ◽  
pp. 34-39 ◽  
Author(s):  
JianBo Zhou ◽  
Minhui Zhang ◽  
ShengChun Piao ◽  
Kashif Iqbal ◽  
Ke Qu ◽  
...  

Data in Brief ◽  
2020 ◽  
Vol 32 ◽  
pp. 106182
Author(s):  
Zainudin Bachok ◽  
Che Din Mohd Safuan ◽  
Nur Hidayah Roseli ◽  
Mohd Fadzil Akhir

2018 ◽  
Author(s):  
Zheng Liu ◽  
Ming Zhu ◽  
Jiao He ◽  
Rong Li ◽  
Sherman Yang

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