A numerical study of the generation mechanism of internal solitary waves in the Luzon Strait

• Published in: Acta oceanologica Sinica Vol. 34; no. 7; pp. 38 - 43
• Main Authors: Wang, Jing, Sun, Meiling, Zhang, Xudong, Sun, Lina, Meng, Junmin
• Format: Journal Article
• Language: English
• Published: Beijing The Chinese Society of Oceanography 01.07.2015; Springer Nature B.V; College of Information and Engineering, 0cean University of China, Qingdao 266100, China%First Institute of 0ceanography, State 0ceanic Administration, Qingdao 266061, China
• Subjects: Climatology; Earth and Environmental Science; Earth Sciences; Ecology; Engineering Fluid Dynamics; Environmental Chemistry; Initial conditions; Instability; Internal tides; Internal waves; Marine & Freshwater Sciences; Mathematical models; Modulation; Oceanography; Schrodinger equation; Solitary waves; Stability; Straits; Stratification; Tidal waves; Wavelength; Waves; 内孤立波; 南海北部; 吕宋海峡; 数值研究; 机理; 能量增益; 调制不稳定性; 非线性Schrodinger方程; Luzon; ISEW, South China Sea; ISEW, Pacific, Luzon Strait; modulation instability; energy gain; internal solitary wave; Luzon Strait; fully nonlinear Schrödinger equation; fully nonlinear Schr?dinger equation
• ISSN: 0253-505X; 1869-1099
• DOI: 10.1007/s13131-015-0695-7

The South China Sea （SCS） is a hot spot for oceanic internal solitary waves due to many factors, such as the complexity of the terrain environment. The internal solitary waves in the northern SCS mainly originate in the Luzon Strait. The generation mechanism of the internal solitary waves in the Luzon Strait is discussed using a modulation instability. The energy gain of the modulation instability is derived based on the fully nonlinear Schr6dinger equation. The peak value of the gain is calculated under different conditions of stratification, wavelength and the initial amplitude of an internal tidal wave. The characteristics of the modulation instability in the Luzon Strait are investigated. The conditions that make the internal tidal wave evolve into an internal solitary wave in the Luzon strait are also obtained. The results show that the internal tide waves can generate the modulation instability in the Luzon Strait and that the maximum gain occur at the eastern sill of the Luzon Strait, where the internal tide waves start to break up into internal solitary trains. The magnitude and the scope of the peak gain are relevant to the stratification and the initial conditions of the internal tide waves. The numerical simulation results are consistent with the in-situ data.