Impact of nonlinear mesoscale eddy on phytoplankton distribution in the northern South China Sea

2013 ◽  
Vol 123-124 ◽  
pp. 33-40 ◽  
Author(s):  
Fenfen Liu ◽  
Shilin Tang ◽  
Chuqun Chen
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Mesoscale Eddy ◽  
China Sea ◽  
Phytoplankton Distribution

Evolution and propagation of a mesoscale eddy in the northern South China Sea during winter

2013 ◽  
Vol 32 (7) ◽  
pp. 1-7 ◽  
Author(s):  
Changjian Liu ◽  
Yan Du ◽  
Wei Zhuang ◽  
Huayong Xia ◽  
Qiang Xie
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Mesoscale Eddy ◽  
China Sea

scholarly journals Features of Intraseasonal Variability Observed in the Upper-Layer Current in the Northern South China Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Wen Xu ◽  
Yeqiang Shu ◽  
Dongxiao Wang ◽  
Ju Chen ◽  
Jinghong Wang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Intraseasonal Variability ◽  
Mesoscale Eddy ◽  
Luzon Strait ◽  
Altimeter Data ◽  
China Sea ◽  
Spatial Differences ◽  
Long Time

This study reveals the features of the strong intraseasonal variability (ISV) of the upper-layer current in the northern South China Sea (NSCS) based on four long-time mooring observations and altimeter data. The ISV of the upper-layer current in the NSCS consists of two dominant periods of 10–65 days and 65–110 days. The ISV with period of 10–65 days is much strong in the Luzon Strait and decays rapidly westward along the slope. The ISV with the period of 65–110 days is relatively strong along the slope with two high cores at 115 and 119°E, whereas it is weak in the Luzon Strait. The 10–65-day ISV can propagate directly from the western Pacific into the NSCS for most of the time. However, due to its long wavelength, the 65–110-day ISV propagates into the NSCS indirectly, possibly similar to the wave diffraction phenomenon. The spatial differences between the two main frequency bands are primarily due to the baroclinic and barotropic instabilities. The spatial distribution of the upper-layer ISV is closely associated with the mesoscale eddy radius of the NSCS. The eddy radius is directly proportional to the strength of 65–110-day ISV, but it is inversely proportional to the strength of 10–65-day ISV.

Spatial structure of turbulent mixing of an anticyclonic mesoscale eddy in the northern South China Sea

2020 ◽  
Vol 39 (11) ◽  
pp. 69-81
Author(s):  
Yongfeng Qi ◽  
Chenjing Shang ◽  
Huabin Mao ◽  
Chunhua Qiu ◽  
Changrong Liang ◽  
...  
Keyword(s):  
South China Sea ◽  
Spatial Structure ◽  
South China ◽  
Turbulent Mixing ◽  
Northern South China Sea ◽  
Mesoscale Eddy ◽  
China Sea

scholarly journals Suppressed Thermocline Mixing in the Center of Anticyclonic Eddy in the North South China Sea

2021 ◽  
Vol 9 (10) ◽  
pp. 1149
Author(s):  
Yongfeng Qi ◽  
Huabin Mao ◽  
Xia Wang ◽  
Linhui Yu ◽  
Shumin Lian ◽  
...  
Keyword(s):  
South China Sea ◽  
Internal Waves ◽  
South China ◽  
Northern South China Sea ◽  
Mesoscale Eddy ◽  
Fine Scale ◽  
Mean Flow ◽  
China Sea ◽  
Flow Interactions ◽  
Background Shear

Direct microstructure observations and fine-scale measurements of an anticyclonic mesoscale eddy were conducted in the northern South China Sea in July 2020. An important finding was that suppressed turbulent mixing in the thermocline existed at the center of the eddy, with an averaged diapycnal diffusivity at least threefold smaller than the peripheral diffusivity. Despite the strong background shear and significant wave–mean flow interactions, the results indicated that the lack of internal wave energy in the corresponding neap tide period during measurement of the eddy’s center was the main reason for the suppressed turbulent mixing in the thermocline. The applicability of the fine-scale parameterization method in the presence of significant wave–mean flow interactions in a mesoscale eddy was evaluated. Overprediction via fine-scale parameterization occurred in the center of the eddy, where the internal waves were inactive; however, the parameterization results were consistent with microstructure observations along the eddy’s periphery, where active internal waves existed. This indicates that the strong background shear and wave–mean flow interactions affected by the mesoscale eddy were not the main contributing factors that affected the applicability of fine-scale parameterization in the northern South China Sea. Instead, our results showed that the activity of internal waves is the most important consideration.

scholarly journals Impacts of a Mesoscale Eddy Pair on Internal Solitary Waves in the Northern South China Sea revealed by Mooring Array Observations

2017 ◽  
Vol 47 (7) ◽  
pp. 1539-1554 ◽  
Author(s):  
Xiaodong Huang ◽  
Zhiwei Zhang ◽  
Xiaojiang Zhang ◽  
Hongbao Qian ◽  
Wei Zhao ◽  
...  
Keyword(s):  
South China Sea ◽  
Solitary Waves ◽  
South China ◽  
Northern South China Sea ◽  
Mesoscale Eddy ◽  
Mesoscale Eddies ◽  
Internal Solitary Waves ◽  
Deep Basin ◽  
Coupled Models ◽  
China Sea

AbstractBoth internal solitary waves (ISWs) and mesoscale eddies are ubiquitous in the northern South China Sea (SCS). In this study, the authors examine the impacts of mesoscale eddies on the ISWs transiting the northern SCS deep basin that evolve from the steepening internal tide generated in the Luzon Strait, using in situ data collected from a specifically designed mooring array. From November 2013 to January 2014, an energetic mesoscale eddy pair consisting of one anticyclonic eddy (AE) and one cyclonic eddy (CE) propagated across the mooring array. Observations revealed that the amplitude, propagation direction, and speed of the transbasin ISWs were significantly modulated by the eddy pair. When the moorings were covered by the southern portion of the AE, the ISW amplitudes decreased by as much as 67% because of the thermocline deepening along the wave direction and the energy divergence along the wave front. When the moorings were covered by the northern portions of both eddies, the amplitude of ISWs also decreased but to a relatively smaller degree. ISWs propagated the fastest inside the southern portion of the AE, where both the thermocline deepening and eddy currents enhanced the propagation speed of ISWs. Under the influence of the AE (CE) core, ISWs propagated more northward (southward) than usual. The observational results reported here highlight the importance of resolving mesoscale eddies in circulation–internal wave coupled models to accurately predict kinematic characteristics of ISWs.

scholarly journals Observed Cross-Shelf Flow Induced by Mesoscale Eddies in the Northern South China Sea

2018 ◽  
Vol 48 (7) ◽  
pp. 1609-1628 ◽  
Author(s):  
Qiang Wang ◽  
Lili Zeng ◽  
Jian Li ◽  
Ju Chen ◽  
Yunkai He ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Mesoscale Eddy ◽  
Mesoscale Eddies ◽  
Baroclinic Mode ◽  
China Sea ◽  
Almost All ◽  
Mode Area ◽  
Shelf Flow

AbstractCross-shelf flow induced by mesoscale eddies has been investigated in the northern South China Sea (NSCS) using velocity observations from Long Ranger ADCP moorings. Mesoscale eddies influenced the three mooring stations during almost all the observation period. Four quadrants have been defined with the mooring location as the origin, and it is found that warm (cold) mesoscale eddies induce onshore (offshore) movement in the eastern two quadrants and offshore (onshore) movement in the western two quadrants. When an eddy propagates past a mooring station, net cross-shelf flow at the mooring station can be induced by asymmetry in the horizontal and vertical structure of the eddy and by its evolution. As an eddy propagates westward, its shape changes continually and the vertical modes also transform from high to lower modes, which contributes to the net cross-shelf flow. Based on the quasigeostrophic potential vorticity equation, it is confirmed that the net cross-shelf flow is mainly induced by the eddy evolution and suppressed by nonlinear effect. Because of dispersion characteristics of the mesoscale eddy, barotropic mode will restructure at the baroclinic mode area after separating from the baroclinic mode, which will be enhanced by topography slope.

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