scholarly journals Distribution and Source Sites of Nonlinear Internal Waves Northeast of Hainan Island

2022 ◽  
Vol 10 (1) ◽  
pp. 55
Author(s):  
Jianjun Liang ◽  
Xiao-Ming Li ◽  
Kaiguo Fan
Keyword(s):  
Internal Waves ◽  
Hainan Island ◽  
Luzon Strait ◽  
Satellite Observations ◽  
Propagation Model ◽  
Tidal Period ◽  
S Waves ◽  
Nonlinear Internal Waves ◽  
Type D ◽  
Good Agreement

The distribution and source sites of nonlinear internal waves (NLIWs) northeast of Hainan Island were investigated using satellite observations and a wavefront propagation model. Satellite observations show two types of NLIWs (here referred to as type-S and type-D waves). The type-S waves are spaced at a semidiurnal tidal period and the type-D waves are spaced at a diurnal tidal period. The spatial distribution of the two types of NLIWs displays a sandwich structure in which the middle region is influenced by both types of NLIWs, and the northern and southern regions are governed by the type-S and type-D waves, respectively. Solving the wavefront model yields good agreement between simulated and observed wavefronts from the Luzon Strait to Hainan Island. We conclude that the NLIWs originate from the Luzon Strait.

scholarly journals Nonlinear internal waves from the Luzon Strait

Eos ◽  
2006 ◽  
Vol 87 (42) ◽  
pp. 449 ◽  
Author(s):  
Cho-Teng Liu ◽  
Robert Pinkel ◽  
Jody Klymak ◽  
Ming-Kuang Hsu ◽  
Hsien-Wen Chen ◽  
...  
Keyword(s):  
Internal Waves ◽  
Luzon Strait ◽  
Nonlinear Internal Waves

MEASUREMENT AND SIMULATION FOR WIND NOISES IN THE OCEAN ENVIRONMENTS WITH NONLINEAR INTERNAL WAVES

2008 ◽  
Vol 16 (02) ◽  
pp. 163-176 ◽  
Author(s):  
HSIANG-CHIH CHAN ◽  
RUEY-CHANG WEI ◽  
CHI-FANG CHEN
Keyword(s):  
Internal Waves ◽  
Sound Speed ◽  
Environmental Changes ◽  
Acoustic Noise ◽  
Propagation Model ◽  
Wind Noise ◽  
Nonlinear Internal Waves ◽  
Line Array ◽  
Noise Data ◽  
Water Temperature Data

This study obtains wind noise variations by experimental data and simulated results to describe meteorological and oceanic effects. The ambient noise data were measured by a vertical line array in the 2001 ASIAEX South China Sea experiment. An acoustic propagation model is used in noise modeling for calculating the sound pressure of noises at receiving sites, including the effects of ocean environmental changes, bottom interactions, and noise fluctuations at different depths. Both range-independent and range-dependent sound speed profiles are generated with in-situ water temperature data. Results show fluctuating noise levels with variations in ocean environments. But the fluctuations are small such that only weak correlation exists in the acoustic noise data and ocean data. Results also indicate that using range-independent sound speed profiles can simulate noise field in range-dependent ocean environments with nonlinear internal waves for shallow regions with flat bottoms.

scholarly journals The Generation and Evolution of Nonlinear Internal Waves in the Deep Basin of the South China Sea

2011 ◽  
Vol 41 (7) ◽  
pp. 1345-1363 ◽  
Author(s):  
Qiang Li ◽  
David M. Farmer
Keyword(s):  
South China Sea ◽  
Internal Waves ◽  
South China ◽  
Internal Tide ◽  
Luzon Strait ◽  
The South China Sea ◽  
The South ◽  
Deep Basin ◽  
Nonlinear Internal Waves ◽  
China Sea

Abstract Time series observations of nonlinear internal waves in the deep basin of the South China Sea are used to evaluate mechanisms for their generation and evolution. Internal tides are generated by tidal currents over ridges in Luzon Strait and steepen as they travel west, subsequently generating high-frequency nonlinear waves. Although nonlinear internal waves appear repeatedly on the western slopes of the South China Sea, their appearance in the deep basin is intermittent and more closely related to the amplitude of the semidiurnal than the predominant diurnal tidal current in Luzon Strait. As the internal tide propagates westward, it evolves under the influence of nonlinearity, rotation, and nonhydrostatic dispersion. The interaction between nonlinearity and rotation transforms the internal tide into a parabolic or corner shape. A fully nonlinear two-layer internal wave model explains the observed characteristics of internal tide evolution in the deep basin for different representative forcing conditions and allows assessment of differences between the fully and weakly nonlinear descriptions. Matching this model to a wave generation solution for representative topography in Luzon Strait leads to predictions in the deep basin consistent with observations. Separation of the eastern and western ridges is close to the internal semidiurnal tidal wavelength, contributing to intensification of the westward propagating semidiurnal component. Doppler effects of internal tide generation, when combined with a steady background flow, suggest an explanation for the apparent suppression of nonlinear wave generation during periods of westward intrusion of the Kuroshio.

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