Effects of westward shoaling pycnocline on characteristics and energetics of internal solitary wave in the Luzon Strait by numerical simulations

Haibin Lü; Yujun Liu; Xiaokang Chen; Guozhen Zha; Shuqun Cai

doi:10.1007/s13131-021-1808-0

Volume 40 Issue 5

May 2021

Turn off MathJax

Article Contents

Abstract

References

Article Navigation > Acta Oceanologica Sinica > 2021 > 40(5): 20-29

ZHUANG Wei, WANG Dongxiao, HU Jianyu, NI Wensheng. Response of the cold water mass in the western South China Sea to the wind stress curl associated with the summer monsoon[J]. Acta Oceanologica Sinica, 2006, (4): 1-13.

Citation:

Haibin Lü, Yujun Liu, Xiaokang Chen, Guozhen Zha, Shuqun Cai. Effects of westward shoaling pycnocline on characteristics and energetics of internal solitary wave in the Luzon Strait by numerical simulations[J]. Acta Oceanologica Sinica, 2021, 40(5): 20-29. doi: 10.1007/s13131-021-1808-0

Citation:

PDF( 1096 KB)

Effects of westward shoaling pycnocline on characteristics and energetics of internal solitary wave in the Luzon Strait by numerical simulations

doi: 10.1007/s13131-021-1808-0

Haibin Lü^{1, 2, 3, 4},
Yujun Liu¹,
Xiaokang Chen¹,
Guozhen Zha¹,
Shuqun Cai^{2, 3, 5, 6
,
,}

1.
Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang 222005, China
2.
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
3.
Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
4.
Jiangsu Institute of Marine Resources Development, Lianyungang 222005, China
5.
University of Chinese Academy of Sciences, Beijing 100049, China
6.
Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou 510301, China

Funds: The Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS) under contract No. QYZDJ-SSW-DQC034; the Talent Project from Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) under contract No. GML2019ZD0304; the National Natural Science Foundation of China (NSFC) under contract Nos 41521005 and 62071207; the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD); the Natural Science Foundation of Huai Hai Institute of Technology under contract No. Z2017006; the Project from Department of Natural Resources of Guangdong Province under contract No. (2020)017; the Open Project of State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, CAS under contract No. LTO1702; Postgraduate Research & Practice Innovation Program of Jiangsu Province under contract No. SJCX19_0963.

More Information

Corresponding author: E-mail: caisq@scsio.ac.cn
Received Date: 2020-03-29
Accepted Date: 2020-12-29

Available Online: 2021-04-29

Publish Date: 2021-05-01

Abstract

Abstract

An internal gravity wave model was employed to simulate the generation of internal solitary waves (ISWs) over a sill by tidal flows. A westward shoaling pycnocline parameterization scheme derived from a three-parameter model was adopted, and then 14 numerical experiments were designed to investigate the influence of the pycnocline thickness, density difference across the pycnocline, westward shoaling isopycnal slope angle and pycnocline depth on the ISWs. When the pycnocline thickness on both sides of the sill increases, the total barotropic kinetic energy, total baroclinic energy and ratio of baroclinic kinetic energy (KE) to available potential energy (APE) decrease, whilst the depth of isopycnal undergoing maximum displacement and ratio of baroclinic energy to barotropic energy increase. When the density difference on both sides of the sill decreases synchronously, the total barotropic kinetic energy, ratio of baroclinic energy to barotropic energy and total baroclinic energy decrease, whilst the depth of isopycnal undergoing maximum displacement increases. When the westward shoaling isopycnal slope angle increases, the total baroclinic energy increases whilst the depth of turning point almost remains unchanged. When the depth of westward shoaling pycnocline on both sides of the sill reduces, the ratio of baroclinic energy to barotropic energy and total baroclinic energy decrease, whilst the total barotropic kinetic energy and ratio of KE to APE increase. When one of the above four different influencing factors was increased by 10% while the other factors keep unchanged, the amplitude of the leading soliton in ISW Packet A was decreased by 2.80%, 7.47%, 3.21% and 6.42% respectively. The density difference across the pycnocline and the pycnocline depth are the two most important factors in affecting the characteristics and energetics of ISWs.
- internal solitary waves,
- baroclinic energy,
- South China Sea,
- pycnocline

FullText(HTML)

References(31)

References

[1]	Bai Xiaolin, Li Xiaofeng, Lamb K G, et al. 2017. Internal solitary wave reflection near Dongsha Atoll, the South China Sea. Journal of Geophysical Research: Oceans, 122(10): 7978–7991. doi: 10.1002/2017JC012880
[2]	Boyer T, Levitus S. 1994. Quality control and processing of historical oceanographic temperature, salinity, and oxygen data. Washington, DC: US Department of Commerce, National Oceanic and Atmospheric Administration, 1–64
[3]	Buijsman M C, McWilliams J C, Jackson C R. 2010. East-west asymmetry in nonlinear internal waves from Luzon Strait. Journal of Geophysical Research: Oceans, 115(C10): C10057. doi: 10.1029/2009JC006004
[4]	Cai Shuqun, Long Xiaomin, Dong Danpeng, et al. 2008. Background current affects the internal wave structure of the northern South China Sea. Progress in Natural Science, 18(5): 585–589. doi: 10.1016/j.pnsc.2007.11.019
[5]	Cao Anzhou, Guo Zheng, Lv Xianqing, et al. 2017. Coherent and incoherent features, seasonal behaviors and spatial variations of internal tides in the northern South China Sea. Journal of Marine Systems, 172: 75–83. doi: 10.1016/j.jmarsys.2017.03.005
[6]	Chen Chenyuan, Hsu J R C, Cheng M H, et al. 2007. An investigation on internal solitary waves in a two-layer fluid: propagation and reflection from steep slopes. Ocean Engineering, 34(1): 171–184. doi: 10.1016/j.oceaneng.2005.11.020
[7]	Chen Zhiwu, Xie Jieshuo, Wang Dongxiao, et al. 2014. Density stratification influences on generation of different modes internal solitary waves. Journal of Geophysical Research: Oceans, 119(10): 7029–7046. doi: 10.1002/2014JC010069
[8]	Chen Zhiwu, Xie Jieshuo, Xu Jiexin, et al. 2013. Energetics of nonlinear internal waves generated by tidal flow over topography. Ocean Modelling, 68: 1–8. doi: 10.1016/j.ocemod.2013.04.008
[9]	Chen Liang, Zheng Quanan, Xiong Xuejun, et al. 2018. A new type of internal solitary waves with a re-appearance period of 23 h observed in the South China Sea. Acta Oceanologica Sinica, 37(9): 116–118. doi: 10.1007/s13131-018-1252-y
[10]	DeCarlo T M, Karnauskas K B, Davis K A, et al. 2015. Climate modulates internal wave activity in the Northern South China Sea. Geophysical Research Letters, 42(3): 831–838. doi: 10.1002/2014GL062522
[11]	Du Tao, Tseng Y H, Yan Xiaohai. 2008. Impacts of tidal currents and Kuroshio intrusion on the generation of nonlinear internal waves in Luzon Strait. Journal of Geophysical Research: Oceans, 113(C8): C08015. doi: 10.1029/2007JC004294
[12]	Grimshaw R, Wang Caixia, Li Lan. 2016. Modelling of polarity change in a nonlinear internal wave train in Laoshan Bay. Journal of Physical Oceanography, 46(3): 965–974. doi: 10.1175/JPO-D-15-0136.1
[13]	Huang Xiaodong, Zhao Wei, Tian Jiwei, et al. 2014. Mooring observations of internal solitary waves in the deep basin west of Luzon Strait. Acta Oceanologica Sinica, 33(3): 82–89. doi: 10.1007/s13131-014-0416-7
[14]	Lamb K G. 2008. On the calculation of the available potential energy of an isolated perturbation in a density-stratified fluid. Journal of Fluid Mechanics, 597: 415–427. doi: 10.1017/S0022112007009743
[15]	Lamb K G. 2010. Energetics of internal solitary waves in a background sheared current. Nonlinear Processes in Geophysics, 17(5): 553–568. doi: 10.5194/npg-17-553-2010
[16]	Lamb K G, Kim J. 2012. Conversion of barotropic tidal energy to internal wave energy over a shelf slope for a linear stratification. Continental Shelf Research, 33: 69–88. doi: 10.1016/j.csr.2011.11.005
[17]	Li Xiaofeng, Jackson C R, Pichel W G. 2013. Internal solitary wave refraction at Dongsha Atoll, South China Sea. Geophysical Research Letters, 40(12): 3128–3132. doi: 10.1002/grl.50614
[18]	Lien R C, D'Asaro E A, Henyey F, et al. 2012. Trapped core formation within a shoaling nonlinear internal wave. Journal of Physical Oceanography, 42(4): 511–525. doi: 10.1175/2011JPO4578.1
[19]	Liu Zihua, Grimshaw R, Johnson E. 2017. Internal solitary waves propagating through variable background hydrology and currents. Ocean Modelling, 116: 134–145. doi: 10.1016/j.ocemod.2017.06.008
[20]	Lü Haibin, Xie Jieshuo, Yao Yuan, et al. 2016. Effect of background parabolic current on characteristics and energetics of internal solitary waves by numerical simulation. Acta Oceanologica Sinica, 35(1): 1–10. doi: 10.1007/s13131-016-0790-4
[21]	Osborne A R, Burch T L. 1980. Internal solitons in the Andaman Sea. Science, 208(4443): 451–460. doi: 10.1126/science.208.4443.451
[22]	Park J H, Farmer D. 2013. Effects of Kuroshio intrusions on nonlinear internal waves in the South China Sea during winter. Journal of Geophysical Research: Oceans, 118(12): 7081–7094. doi: 10.1002/2013JC008983
[23]	Vázquez A, Bruno M, Izquierdo A, et al. 2008. Meteorologically forced subinertial flows and internal wave generation at the main sill of the Strait of Gibraltar. Deep Sea Research Part I: Oceanographic Research Papers, 55(10): 1277–1283. doi: 10.1016/j.dsr.2008.05.008
[24]	Wang Gang. 2006. Numerical modelling on the generation process of the tidal internal waves over the northwestern South China Sea shelf (in Chinese)[dissertation]. Qingdao: Institute of Oceanology, Chinese Academy of Sciences
[25]	Wang Juan, Huang Weigen, Yang Jingsong, et al. 2012. Study of the propagation direction of the internal waves in the South China Sea using satellite images. Acta Oceanologica Sinica, 32(5): 42–50
[26]	Xie Jieshuo, He Yinghui, Chen Zhiwu, et al. 2015. Simulations of internal solitary wave interactions with mesoscale eddies in the northeastern South China Sea. Journal of Physical Oceanography, 45(12): 2959–2978. doi: 10.1175/JPO-D-15-0029.1
[27]	Xu Zhenhua, Liu Kun, Yin Baoshu, et al. 2016. Long-range propagation and associated variability of internal tides in the South China Sea. Journal of Geophysical Research: Oceans, 121(11): 8268–8286. doi: 10.1002/2016JC012105
[28]	Zhao Zhongxiang. 2014. Internal tide radiation from the Luzon Strait. Journal of Geophysical Research: Oceans, 119(8): 5434–5448. doi: 10.1002/2014JC010014
[29]	Zheng Quanan, Song Y T, Lin Hui, et al. 2008. On generation source sites of internal waves in the Luzon Strait. Acta Oceanologica Sinica, 27(3): 38–50
[30]	Zheng Quanan, Susanto R D, Ho C R, et al. 2007. Statistical and dynamical analyses of generation mechanisms of solitary internal waves in the northern South China Sea. Journal of Geophysical Research: Oceans, 112(C3): C03021. doi: 10.1029/2006JC003551
[31]	Zheng Quanan, Susanto R D, Yan Xiaohai, et al. 1998. Observation of equatorial Kelvin solitary waves in a slowly varying thermocline. Nonlinear Processes in Geophysics, 5: 153–165. doi: 10.5194/npg-5-153-1998