Observations of nonlinear internal waves of tidal origin in the northeastern East China Sea

2021 ◽  
Author(s):  
Seung-Woo Lee ◽  
SungHyun Nam
Keyword(s):  
East China Sea ◽  
Internal Waves ◽  
Spring Tide ◽  
Propagation Speed ◽  
East China ◽  
Multiple Sources ◽  
Flat Bottom ◽  
Nonlinear Internal Waves ◽  
China Sea ◽  
Regional Circulation

<p>Oceanic nonlinear internal waves (NLIWs) play an important role in regional circulation, biogeochemistry, energetics, vertical mixing, underwater acoustics, marine engineering, and submarine navigation, most commonly generated by the interaction between barotropic tides and bathymetry. Here, we present characteristics of first mode NLIWs observed using high-resolution in-situ data collected using moored and underway temperature sensors in a relatively flat bottom in the northeastern East China Sea during May 15-28, 2015. During the experiment, totally 34 events of first mode NLIWs were identified and characterized with amplitude of 4–16 m, characteristic width of 310–610 m, propagation speed of 0.53–0.56 m s<sup>-1</sup>, and propagation direction (mainly southwestward propagation), respectively. Most NLIWs were observed during period of spring tide with phases locked to semidiurnal barotropic tides. Generation and propagation of the first mode NLIWs observed in the region are discussed in relation to satellite images and historical hydrographic data collected in the region. Our results support significance of first mode NLIWs and their interactions on turbulent mixing and regional circulation particularly in a broad and shallow continental shelves where the NLIWs generated from multiple sources propagate into multi-directions experiencing wave-wave interactions.</p>

Propagation and transformation of nonlinear internal waves of tidal origin observed in the northeastern East China Sea

2020 ◽  
Author(s):  
Seung-Woo Lee ◽  
SungHyun Nam
Keyword(s):  
East China Sea ◽  
Internal Waves ◽  
Bottom Topography ◽  
Wave Interaction ◽  
Propagation Speed ◽  
East China ◽  
Modal Interactions ◽  
Nonlinear Internal Waves ◽  
China Sea ◽  
Mode 2

<p>Oceanic nonlinear internal waves (NLIWs) play an important role in regional circulation, biogeochemistry, energetics, vertical mixing, and underwater acoustics, causing hazards to marine engineering and submarine navigation. Mainly generated by the interaction of the barotropic tides with the bottom topography, they propagate and transform due to wave-wave interaction process. Here, we present characteristics of first two modes of NLIWs observed using high-resolution spatiotemporal data collected in a relatively flat area in the northeastern East China Sea in May 2015. Six groups of NLIWs were identified from the observations: four groups of mode-1 and two groups of mode-2. The amplitude, propagation speed, and characteristic width of mode-1 NLIWs had ranges of 4–16 m, 0.53–0.56 m s<sup>-1</sup>, and 310–610 m, respectively. The mode-2 NLIWs propagate eastward slowly with a speed less than 0.37 m s<sup>-1</sup> with a comparable amplitude of 4–14 m and longer characteristic width of 540–1920 m. Intermodal interactions may take a role in the evolution of mode-1 NLIWs west of the observational area. Our results characterizing the two modes of NLIWs highlight the significance of propagation and transformation of NLIWs and their modal interactions on a broad and shallow shelf.</p>

scholarly journals Episodes of nonlinear internal waves in the northern East China Sea

2006 ◽  
Vol 33 (18) ◽  
pp. n/a-n/a ◽  
Author(s):  
Jae Hak Lee ◽  
Iossif Lozovatsky ◽  
Sung-Tae Jang ◽  
Chan Joo Jang ◽  
Chang Su Hong ◽  
...  
Keyword(s):  
East China Sea ◽  
Internal Waves ◽  
East China ◽  
Nonlinear Internal Waves ◽  
China Sea

Effect of internal waves on acoustic energy structure in the northern East China Sea

2016 ◽  
Vol 140 (4) ◽  
pp. 3064-3064
Author(s):  
Jungyong Park ◽  
Sangkyum An ◽  
Youngmin Choo ◽  
Woojae Seong
Keyword(s):  
East China Sea ◽  
Internal Waves ◽  
Acoustic Energy ◽  
East China ◽  
Energy Structure ◽  
China Sea

scholarly journals Variation and Episodes of Near-Inertial Internal Waves on the Continental Slope of the Southeastern East China Sea

2021 ◽  
Vol 9 (8) ◽  
pp. 916
Author(s):  
Bing Yang ◽  
Po Hu ◽  
Yijun Hou
Keyword(s):  
Continental Slope ◽  
East China Sea ◽  
Internal Waves ◽  
Low Frequency ◽  
Blue Shift ◽  
Vertical Shear ◽  
East China ◽  
Left Hand ◽  
China Sea ◽  
Generation Mechanisms

Based on in situ observations, six episodes of near-inertial internal waves (NIWs) were detected on the East China Sea (ECS) continental slope, and the mechanisms and characteristics of them were examined. The generation mechanisms of the observed NIWs included typhoon, wind burst, lateral propagation, and energy transfer from low-frequency flow. The depth-integrated near-inertial kinetic energy (NIKE) showed no significant seasonal variation, and the annual mean NIKE and near-inertial currents were 400 J/m2 and 3.50 cm/s, respectively. Downward propagation of NIKE was evident in the small wavenumber band according to the rotary vertical wavenumber spectra. The NIKE was subsurface-intensified, and the near-inertial vertical shear reached 0.01 s−1. The vertical phase speeds of the NIWs ranged from 5 to 19 m/h. The frequencies of the NIWs were mostly red-shifted, however, blue-shift also existed. One episode had both blue- and red-shifted frequencies vertically, and had both upward and downward propagating vertical phase speeds. The e-folding times of the observed NIWs ranged from 4 to 11 days, which were influenced by successive wind bursts and background vorticity. On the left-hand side of Kuroshio, the background vorticity is usually positive; however, the NIWs were almost red-shifted, which resulted from the Doppler shift of the Kuroshio.

Sign in / Sign up

Export Citation Format

Share Document