On the vertical structure of internal solitary waves in the northeastern South China Sea.

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Publisher: Elsevier B.V.
Document Type: Report; Brief article
Length: 320 words

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Abstract :

Keywords Internal solitary waves; Vertical structure; South China Sea; Seismic oceanography; EMD algorithm Highlights * The seismic oceanography can observe the fine vertical structure of ISW. * The vertical structure of ISW is mainly determined by nonlinearity. * The vertical structure of ISW may be affected by its own amplitude, water depth, topography and background flow. * Eddy can reduce the amplitude of ISW and affect the vertical structure. Abstract Internal solitary waves (ISWs) make important contributions to the energy cascade, ocean mixing and material transport in the ocean. However, there are few observational studies on the vertical structure of ISWs. In this article, we describe and analyze 11 ISWs near Dongsha Atoll in the South China Sea directly observed using two-dimensional seismic data. We calculate the vertical structures of these ISWs, and compared them with two theories. We find that three ISWs conform to the linear vertical structure function, four conform to the first-order nonlinear vertical structure function, and the remaining conform to neither function. We use the empirical mode decomposition (EMD) method to analyze reasons for the difference between the observed and theoretical vertical structures. The results show that the vertical structure is mainly determined by nonlinearity, which is an important dynamic characteristics of ISW. Therefore, whether the theory conforms to the observation depends on the ability of theory to describe the nonlinear characteristics of ISWs. In addition, topography and background flow affect the vertical structure. Author Affiliation: (a) State Key Laboratory of Marine Geology, School of Ocean and Earth Science, Tongji University, Shanghai, 200092, China (b) Applied Physics Laboratory, University of Washington, Seattle, WA, USA (c) MNR Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, China Geological Survey, Guangzhou, 510760, China * Corresponding author. Article History: Received 3 December 2020; Revised 20 April 2021; Accepted 21 April 2021 Byline: Yi Gong (a), Haibin Song [hbsong@tongji.edu.cn] (a,*), Zhongxiang Zhao (b), Yongxian Guan (c), Yunyan Kuang (a)

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Gale Document Number: GALE|A664259230