Abstract
A nine-month mooring record was used to investigate seasonal variation and modal content of internal tides (ITs) on the continental slope in the northern South China Sea (SCS). Diurnal tides at this site show clear seasonal change with higher energy in winter than in spring and autumn, whereas semidiurnal tides show the opposite seasonal pattern. The consistency of ITs with barotropic tides within the Luzon Strait, which is the generation region of the ITs, implies that the seasonal variation of ITs depends on their astronomical forcing, even after extended propagation across the SCS basin. Diurnal tides also differ from semidiurnal tides in relation to modal content; they display signals of high modes while semidiurnal tides are dominated by low modes. Reflection of the diurnal tides on the continental slope serves as a reasonable explanation for their high modes. Both diurnal and semidiurnal tides are composed of a larger proportion of coherent components that have a regular 14-day spring-neap cycle. The coherent components are dominated by low modes and they show obvious seasonal variation, while the incoherent components are composed mainly of higher modes and they display intermittent characteristics.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Alford M H, MacKinnon J A, Nash J D, Simmons H, Pickering A, Klymak J M, Pinkel R, Sun O, Rainville L, Musgrave R, Beitzel T, Fu K H, Lu C W. 2011. Energy flux and dissipation in Luzon Strait: two tales of two ridges. Journal of Physical Oceanography, 41 (11): 2 211–2 222.
Alford M H, Peacock T, MacKinnon J A et al. 2015. The formation and fate of internal waves in the South China Sea. Nature, 521 (7550): 65–69.
Buijsman M C, Kanarska Y, McWilliams J C. 2010. On the generation and evolution of nonlinear internal waves in the South China Sea. Journal of Geophysical Research, 115 (C2): C02012.
Cao A Z, Guo Z, Lv X Q, Song J B, Zhang J C. 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.
Cao A Z, Li B T, Lv X Q. 2015. Extraction of internal tidal currents and reconstruction of full-depth tidal currents from mooring observations. Journal of Atmospheric and Oceanic Technology, 32 (7): 1 414–1 424.
Dong J H, Zhao W, Chen H T, Meng Z C, Shi X C, Tian J W. 2015. Asymmetry of internal waves and its effects on the ecological environment observed in the northern South China Sea. Deep Sea Research Part I: Oceanographic Research Papers, 98: 94–101.
Duda T F, Lynch J F, Irish J D, Beardsley R C, Ramp S R, Chiu C S, Tang T Y, Yang Y J. 2004. Internal tide and nonlinear internal wave behavior at the continental slope in the northern South China Sea. IEEE Journal of Oceanic Engineering, 29 (4): 1 105–1 130.
Duda T F, Rainville L. 2008. Diurnal and semidiurnal internal tide energy flux at a continental slope in the South China Sea. Journal of Geophysical Research, 113 (C3): C03025.
Egbert G D, Erofeeva S Y. 2002. Efficient inverse modeling of Barotropic ocean tides. Journal of Atmospheric and Oceanic Technology, 19 (2): 183–204.
Eriksen C C. 1982. Observations of internal wave reflection offsloping bottoms. Journal of Geophysical Research, 87 (C1): 525–538.
Eriksen C C. 1985. Implications of ocean bottom reflection for internal wave spectra and mixing. Journal of Physical Oceanography, 15 (9): 1 145–1 156.
Fliegel M, Hunkins K. 1975. Internal wave dispersion calculated using the Thomson-Haskell method. Journal of Physical Oceanography, 5 (3): 541–548.
Guo P, Fang W D, Liu C J, Qiu F W. 2012. Seasonal characteristics of internal tides on the continental shelf in the northern South China Sea. Journal of Geophysical Research, 117 (C4): C04023.
Haskell N A. 1953. The dispersion of surface waves on multilayered media. Bulletin of the Seismological Society of America, 43 (1): 17–34.
Huang X D, Chen Z H, Zhao W, Zhang Z W, Zhou C, Yang Q X, Tian J W. 2016. An extreme internal solitary wave event observed in the northern South China Sea. Scientific Reports, 6: 30041, https://doi.org/10.1038/srep30041.
Huang X D, Zhang Z W, Zhang X J, Qian H B, Zhao W, Tian J W. 2017. Impacts of a mesoscale eddy pair on internal solitary waves in the northern South China Sea revealed by mooring array observations. Journal of Physical Oceanography, https://doi.org/10.1175/JPO-D-16-0111.1.
Jan S, Chern C S, Wang J, Chiou M D. 2012. Generation and propagation of baroclinic tides modified by the Kuroshio in the Luzon Strait. Journal of Geophysical Research, 117 (C2): C02019.
Jan S, Lien R C, Ting C H. 2008. Numerical study of baroclinic tides in Luzon Strait. Journal of Oceanography, 64 (5): 789–802.
Klymak J M, Alford M H, Pinkel R, Lien R C, Yang Y J, Tang T Y. 2011. The breaking and scattering of the internal tide on a continental slope. Journal of Physical Oceanography, 41 (5): 926–945.
Liu A K, Ramp S R, Zhao Y H, Tang T Y. 2004. A case study of internal solitary wave propagation during ASIAEX 2001. IEEE Journal of Oceanic Engineering, 29 (4): 1 144–1 156.
Liu J L, He Y H, Wang D X, Liu T Y, Cai S Q. 2015. Observed enhanced internal tides in winter near the Luzon Strait. Journal of Geophysical Research, 120 (10): 6 637–6 652.
Liu Q, Xie X H, Shang X D, Chen G Y. 2016. Coherent and incoherent internal tides in the southern South China Sea. Chinese Journal of Oceanology and Limnology, 34 (6): 1 374–1 382.
Ma B B, Lien R C, Ko D S. 2013. The variability of internal tides in the Northern South China Sea. Journal of Oceanography, 69 (5): 619–630.
Nash J D, Kunze E, Toole J M, Schmitt R W. 2004. Internal tide reflection and turbulent mixing on the continental slope. Journal of Physical Oceanography, 34 (5): 1 117–1 134.
Pawlowicz R, Beardsley B, Lentz S. 2002. Classical tidal harmonic analysis including error estimates in MATLAB using T_TIDE. Computers & Geosciences, 28 (8): 929–937.
Ramp S R, Tang T Y, Duda T F, Lynch J F, Liu A K, Chiu C S, Bahr F L, Kim H R, Yang Y J. 2004. Internal solitons in the northeastern South China Sea. Part I: sources and deep water propagation. IEEE Journal of Oceanic Engineering, 29 (4): 1 157–1 181.
Shang X D, Liu Q, Xie X H, Chen G Y, Chen R Y. 2015. Characteristics and seasonal variability of internal tides in the southern South China Sea. Deep Sea Research Part I: Oceanographic Research Papers, 98: 43–52.
Shaw P T, Ko D S, Chao S Y. 2009. Internal solitary waves induced by flow over a ridge: with applications to the northern South China Sea. Journal of Geophysical Research, 114 (C2): C02019.
Thomson W T. 1950. Transmission of elastic waves through a stratified solid medium. Journal of Applied Physics, 21 (2): 89–93.
Tian J W, Yang Q X, Zhao W. 2009. Enhanced diapycnal mixing in the South China Sea. Journal of Physical Oceanography, 39 (12): 3 191–3 203, https://doi.org/10.1175/2009JPO3899.1.
Vlasenko V, Stashchuk N, Guo C, Chen X. 2010. Multimodal structure of baroclinic tides in the South China Sea. Nonlinear Processes in Geophysics, 17 (5): 529–543.
Wu L D, Miao C B, Zhao W. 2013. Patterns of K 1 and M 2 internal tides and their seasonal variations in the northern South China Sea. Journal of Oceanography, 69 (4): 481–494.
Xu Z H, Yin B S, Hou Y J, Liu A K. 2014. Seasonal variability and north-south asymmetry of internal tides in the deep basin west of the Luzon Strait. Journal of Marine Systems, 134: 101–112.
Xu Z H, Yin B S, Hou Y J, Xu Y S. 2013. Variability of internal tides and near-inertial waves on the continental slope of the northwestern South China Sea. Journal of Geophysical Research, 118 (1): 197–211.
Zhang Z W, Tian J W, Qiu B, Zhao W, Chang P, Wu D X, Wan X Q. 2016. Observed 3D structure, generation, and dissipation of oceanic mesoscale eddies in the South China Sea. Scientific Reports, 6: 24 349.
Zhang Z W, Zhao W, Qiu B, Tian J W. 2017. Anticyclonic eddy sheddings from Kuroshio loop and the accompanying cyclonic eddy in the northeastern South China Sea. Journal of Physical Oceanography, https://doi.org/10.1175/JPO-D-16-0185.1.
Zhang Z W, Zhao W, Tian J W, Liang X F. 2013. A mesoscale eddy pair southwest of Taiwan and its influence on deep circulation. Journal of Geophysical Research, 118 (12): 6 479–6 494.
Zhang Z W, Zhao W, Tian J W, Yang Q X, Qu T D. 2015. Spatial structure and temporal variability of the zonal flow in the Luzon Strait. Journal of Geophysical Research, 120 (2): 759–776.
Zhao W, Zhou C, Tian J W, Yang Q X, Wang B, Xie L L, Qu T D. 2014. Deep water circulation in the Luzon Strait. Journal of Geophysical Research, 119 (2): 790–804.
Zhao Z X, Alford M H, Lien R C, Gregg M C, Carter G S. 2012. Internal tides and mixing in a submarine canyon with time-varying stratification. Journal of Physical Oceanography, 42 (12): 2 121–2 142.
Zhao Z X. 2014. Internal tide radiation from the Luzon Strait. Journal of Geophysical Research, 119 (8): 5 434–5 448.
Zhou C, Zhao W, Tian J W, Yang Q X, Qu T D. 2014. Variability of the deep-water overflow in the Luzon strait. Journal of Physical Oceanography, 44 (11): 2 972–2 986.
Acknowledgement
The mooring data used this paper were obtained by the South China Sea Mooring Array constructed by the Ocean University of China. The authors deeply thank Professor TIAN Jiwei for providing the mooring data.
Author information
Authors and Affiliations
Corresponding author
Additional information
Supported by the China Postdoctoral Science Foundation (No. 2017M611979), the National Natural Science Foundation of China (Nos. 41606006, 41371496), the Natural Science Foundation of Zhejiang Province (No. LY15D060001), the National High Technology Research and Development Program of China (863 Program) (No. 2013AA09A502), the National Key Technology Research and Development Program (No. 2013BAK05B04), and the 111 Project of Ministry of Education of China (No. B07036)
Rights and permissions
About this article
Cite this article
Guo, Z., Cao, A. & Lü, X. Seasonal variation and modal content of internal tides in the northern South China Sea. J. Ocean. Limnol. 36, 651–662 (2018). https://doi.org/10.1007/s00343-018-6352-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00343-018-6352-1