• Alford, M. H., and et al. , 2015: The formation and fate of internal waves in the South China Sea. Nature, 521, 6569, https://doi.org/10.1038/nature14399.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cai, Z., and J. Gan, 2019: Coupled external-internal dynamics of layered circulation in the South China Sea: A modeling study. J. Geophys. Res. Oceans, 124, 50395053, https://doi.org/10.1029/2019JC014962.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cai, Z., and J. Gan, 2020: Dynamics of the cross-layer exchange for the layered circulation in the South China Sea. J. Geophys. Res. Oceans, 125, e2020JC016131, https://doi.org/10.1029/2020JC016131.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cessi, P., N. Pinardi, and V. Lyubartsev, 2014: Energetics of semienclosed basins with two-layer flows at the strait. J. Phys. Oceanogr., 44, 967979, https://doi.org/10.1175/JPO-D-13-0129.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chang, M.-H., R.-C. Lien, T. Y. Tang, E. A. D'Asaro, and Y. J. Yang, 2006: Energy flux of nonlinear internal waves in northern South China Sea. Geophys. Res. Lett., 33, L03607, https://doi.org/10.1029/2005GL025196.

    • Crossref
    • Export Citation
  • Chen, G., Y. Hou, X. Chu, and P. Qi, 2009: The variability of eddy kinetic energy in the South China Sea deduced from satellite altimeter data. Chin. J. Oceanology Limnol., 27, 943954, https://doi.org/10.1007/s00343-009-9297-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, R., A. F. Thompson, and G. R. Flierl, 2016: Time-dependent eddy-mean energy diagrams and their application to the ocean. J. Phys. Oceanogr., 46, 28272850, https://doi.org/10.1175/JPO-D-16-0012.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cheng, X. H., and Y. Q. Qi, 2010: Variations of eddy kinetic energy in the South China Sea. J. Oceanogr., 66, 8594, https://doi.org/10.1007/s10872-010-0007-y.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Fang, G., Y. Wang, Z. Wei, Y. Fang, F. Qiao, and X. Hu, 2009: Interocean circulation and heat and freshwater budgets of the South China Sea based on a numerical model. Dyn. Atmos. Oceans, 47, 5572, https://doi.org/10.1016/j.dynatmoce.2008.09.003.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ferrari, R., and C. Wunsch, 2009: Ocean circulation kinetic energy: Reservoirs, sources, and sinks. Annu. Rev. Fluid Mech., 41, 253282, https://doi.org/10.1146/annurev.fluid.40.111406.102139.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gan, J., and T. Qu, 2008: Coastal jet separation and associated flow variability in the southwest South China Sea. Deep-Sea Res. I, 55, 119, https://doi.org/10.1016/j.dsr.2007.09.008.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gan, J., H. Li, E. N. Curchitser, and D. B. Haidvogel, 2006: Modeling South China sea circulation: Response to seasonal forcing regimes. J. Geophys. Res. Oceans, 111, C06034, https://doi.org/10.1029/2005JC003298.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gan, J., H. San Ho, and L. Liang, 2013: Dynamics of intensified downwelling circulation over a widened shelf in the northeastern South China Sea. J. Phys. Oceanogr., 43, 8094, https://doi.org/10.1175/JPO-D-12-02.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gan, J., Z. Liu, and C. R. Hui, 2016a: A three-layer alternating spinning circulation in the South China Sea. J. Phys. Oceanogr., 46, 23092315, https://doi.org/10.1175/JPO-D-16-0044.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gan, J., Z. Liu, and L. Liang, 2016b: Numerical modeling of intrinsically and extrinsically forced seasonal circulation in the China Seas: A kinematic study. J. Geophys. Res. Oceans, 121, 46974715, https://doi.org/10.1002/2016JC011800.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Greatbatch, R. J., X. Zhai, M. Claus, L. Czeschel, and W. Rath, 2010: Transport driven by eddy momentum fluxes in the Gulf Stream Extension region. Geophys. Res. Lett., 37, L24401, https://doi.org/10.1029/2010GL045473.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Huang, X., Z. Chen, W. Zhao, Z. Zhang, C. Zhou, Q. Yang, and J. Tian, 2016: An extreme internal solitary wave event observed in the northern South China Sea. Sci. Rep., 6, 30041, https://doi.org/10.1038/srep30041.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kang, D., and E. N. Curchitser, 2015: Energetics of eddy–mean flow interactions in the Gulf Stream region. J. Phys. Oceanogr., 45, 11031120, https://doi.org/10.1175/JPO-D-14-0200.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lan, J., N. Zhang, and Y. Wang, 2013: On the dynamics of the South China Sea deep circulation. J. Geophys. Res. Oceans, 118, 12061210, https://doi.org/10.1002/jgrc.20104.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lan, J., Y. Wang, F. Cui, and N. Zhang, 2015: Seasonal variation in the South China Sea deep circulation. J. Geophys. Res. Oceans, 120, 16821690, https://doi.org/10.1002/2014JC010413.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, Z., and J. Gan, 2016: Open boundary conditions for tidally and subtidally forced circulation in a limited-area coastal model using the Regional Ocean Modeling System (ROMS). J. Geophys. Res. Oceans, 121, 61846203, https://doi.org/10.1002/2016JC011975.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, Z., and J. Gan, 2017: Three-dimensional pathways of water masses in the south China Sea: A modeling study. J. Geophys. Res. Oceans, 122, 60396054, https://doi.org/10.1002/2016JC012511.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Magalhães, F. C., J. L. L. Azevedo, and L. R. Oliveira, 2017: Energetics of eddy-mean flow interactions in the Brazil Current between 20°S and 36°S. J. Geophys. Res. Oceans, 122, 61296146, https://doi.org/10.1002/2016JC012609.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Masumoto, Y., H. Sasaki, T. Kagimoto, and N. Komori, 2004: A fifty-year eddy-resolving simulation of the world ocean–preliminary outcomes of OFES (OGCM for the Earth Simulator). J. Earth Simul., 1, 3556.

    • Search Google Scholar
    • Export Citation
  • Mellor, G. L., and T. Yamada, 1982: Development of a turbulence closure model for geophysical fluid problems. Rev. Geophys. Space Phys., 20, 851875, https://doi.org/10.1029/RG020i004p00851.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nan, F., H. Xue, and F. Yu, 2015: Kuroshio intrusion into the South China Sea: A review. Prog. Oceanogr., 137, 314–333, https://doi.org/10.1016/j.pocean.2014.05.012.

    • Crossref
    • Export Citation
  • Noh, Y., B. Y. Yim, S. H. You, J. H. Yoon, and B. Qiu, 2007: Seasonal variation of eddy kinetic energy of the North Pacific Subtropical Countercurrent simulated by an eddy-resolving OGCM. Geophys. Res. Lett., 34, L07601, https://doi.org/10.1029/2006GL029130.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Qiu, B., 1999: Seasonal eddy field modulation of the North Pacific subtropical countercurrent: TOPEX/Poseidon observations and theory. J. Phys. Oceanogr., 29, 24712486, https://doi.org/10.1175/1520-0485(1999)029<2471:SEFMOT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Qu, T., J. B. Girton, and J. A. Whitehead, 2006: Deepwater overflow through Luzon Strait. J. Geophys. Res., 111, C01002, https://doi.org/10.1029/2005JC003139.

    • Search Google Scholar
    • Export Citation
  • Qu, T., Y. T. Song, and T. Yamagata, 2009: An introduction to the South China Sea throughflow: Its dynamics, variability, and application for climate. Dyn. Atmos. Oceans, 47, 314, https://doi.org/10.1016/j.dynatmoce.2008.05.001.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Quan, Q., and H. Xue, 2018: Layered model and insights into the vertical coupling of the South China Sea circulation in the upper and middle layers. Ocean Modell., 129, 7592, https://doi.org/10.1016/j.ocemod.2018.06.006.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Quan, Q., and H. Xue, 2019: Influence of abyssal mixing on the multilayer circulation in the South China Sea. J. Phys. Oceanogr., 49, 30453060, https://doi.org/10.1175/JPO-D-19-0020.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Richardson, P. L., 1983: Eddy kinetic energy in the North Atlantic from surface drifters. J. Geophys. Res., 88, 43554367, https://doi.org/10.1029/JC088iC07p04355.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shchepetkin, A. F., and J. C. McWilliams, 2005: The Regional Ocean Modeling System (ROMS): A split-explicit, free-surface, topography following coordinates ocean model. Ocean Modell., 9, 347404, https://doi.org/10.1016/j.ocemod.2004.08.002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shu, Y., H. Xue, D. Wang, F. Chai, Q. Xie, J. Yao, and J. Xiao, 2014: Meridional overturning circulation in the South China Sea envisioned from the high-resolution global reanalysis data GLBa0.08. J. Geophys. Res. Oceans, 119, 30123028, https://doi.org/10.1002/2013JC009583.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Stammer, D., 1997: Global characteristics of ocean variability estimated from regional TOPEX/Poseidon altimeter measurements. J. Phys. Oceanogr., 27, 17431769, https://doi.org/10.1175/1520-0485(1997)027<1743:GCOOVE>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Su, J., 2004: Overview of the South China Sea circulation and its influence on the coastal physical oceanography outside the Pearl River Estuary. Cont. Shelf Res., 24, 17451760, https://doi.org/10.1016/j.csr.2004.06.005.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tian, J., Q. Yang, and W. Zhao, 2009: Enhanced diapycnal mixing in the South China Sea. J. Phys. Oceanogr., 39, 31913203, https://doi.org/10.1175/2009JPO3899.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, G., J. Su, and P. C. Chu, 2003: Mesoscale eddies in the South China Sea observed with altimeter data. Geophys. Res. Lett., 30, 2121, https://doi.org/10.1029/2003GL018532.

    • Crossref
    • Export Citation
  • Wang, G., S.-P. Xie, T. Qu, and R. X. Huang, 2011: Deep South China Sea circulation. Geophys. Res. Lett., 38, L05601, https://doi.org/10.1029/2010GL046626.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, H., D. Wang, G. Liu, H. Wu, and M. Li, 2012: Seasonal variation of eddy kinetic energy in the South China Sea. Acta Oceanol. Sin., 31, 115, https://doi.org/10.1007/s13131-012-0170-7.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, X., S. Peng, Z. Liu, R. X. Huang, Y. K. Qian, and Y. Li, 2016: Tidal mixing in the South China Sea: An estimate based on the internal tide energetics. J. Phys. Oceanogr., 46, 107124, https://doi.org/10.1175/JPO-D-15-0082.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, X., Z. Liu, and S. Peng, 2017: Impact of tidal mixing on water mass transformation and circulation in the South China Sea. J. Phys. Oceanogr., 47, 419432, https://doi.org/10.1175/JPO-D-16-0171.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wyrtki, K., L. Magaard, and J. Hager, 1976: Eddy energy in the oceans. J. Geophys. Res., 81, 26412646, https://doi.org/10.1029/JC081i015p02641.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xu, F.-H., and L.-Y. Oey, 2014: State analysis using the local ensemble transform Kalman filter (LETKF) and the three-layer circulation structure of the Luzon Strait and the South China Sea. Ocean Dyn., 64, 905923, https://doi.org/10.1007/s10236-014-0720-y.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xu, Z., K. Liu, B. Yin, Z. Zhao, Y. Wang, and Q. Li, 2016: Long-range propagation and associated variability of internal tides in the South China Sea. J. Geophys. Res. Oceans, 121, 82688286, https://doi.org/10.1002/2016JC012105.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xue, H., F. Chai, N. Pettigrew, D. Xu, M. Shi, and J. Xu, 2004: Kuroshio intrusion and the circulation in the South China Sea. J. Geophys. Res. Oceans, 109, C02017, https://doi.org/10.1029/2002JC001724.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yang, H., Q. Liu, Z. Liu, D. Wang, and X. Liu, 2002: A general circulation model study of the dynamics of the upper ocean circulation of the South China Sea. J. Geophys. Res., 107, 3085, https://doi.org/10.1029/2001JC001084.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yang, H., L. Wu, H. Liu, and Y. Yu, 2013: Eddy energy sources and sinks in the South China Sea. J. Geophys. Res. Oceans, 118, 47164726, https://doi.org/10.1002/jgrc.20343.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yang, J., and J. F. Price, 2000: Water-mass formation and potential vorticity balance in an abyssal ocean circulation. J. Mar. Res., 58, 789–808, https://doi.org/10.1357/002224000321358918.

    • Crossref
    • Export Citation
  • Yang, Q., J. Tian, W. Zhao, X. Liang, and L. Zhou, 2014: Observations of turbulence on the shelf and slope of northern South China Sea. Deep-Sea Res. I, 87, 4352, https://doi.org/10.1016/j.dsr.2014.02.006.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yang, Q., M. Nikurashin, H. Sasaki, H. Sun, and J. Tian, 2019: Dissipation of mesoscale eddies and its contribution to mixing in the northern South China Sea. Sci. Rep., 9, 556, https://doi.org/10.1038/s41598-018-36610-x.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yuan, D., 2002: A numerical study of the South China Sea deep circulation and its relation to the Luzon Strait transport. Acta Oceanol. Sin., 21, 187202.

    • Search Google Scholar
    • Export Citation
  • Zhang, Z., W. Zhao, B. Qiu, and J. Tian, 2017: Anticyclonic eddy sheddings from Kuroshio loop and the accompanying cyclonic eddy in the northeastern South China Sea. J. Phys. Oceanogr., 47, 12431259, https://doi.org/10.1175/JPO-D-16-0185.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhao, W., C. Zhou, J. Tian, Q. Yang, B. Wang, L. Xie, and T. Qu, 2014: Deep water circulation in the Luzon Strait. J. Geophys. Res. Oceans, 119, 790–804, https://doi.org/10.1002/2013JC009587.

    • Crossref
    • Export Citation
  • Zhu, Y., J. Sun, Y. Wang, Z. Wei, D. Yang, and T. Qu, 2017: Effect of potential vorticity flux on the circulation in the South China Sea. J. Geophys. Res. Oceans, 122, 64546469, https://doi.org/10.1002/2016JC012375.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhu, Y., J. Sun, Y. Wang, S. Li, T. Xu, Z. Wei, and T. Qu, 2019: Overview of the multi-layer circulation in the South China Sea. Prog. Oceanogr., 175, 171–182, https://doi.org/10.1016/j.pocean.2019.04.001.

    • Crossref
    • Export Citation
  • Zu, T., J. Gan, and S. Erofeeva, 2008: Numerical study of the tide and tidal dynamics in the South China Sea. Deep-Sea Res. I, 55, 137154, https://doi.org/10.1016/j.dsr.2007.10.007.

    • Crossref
    • Search Google Scholar
    • Export Citation
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Dynamics of the Layered Circulation Inferred from Kinetic Energy Pathway in the South China Sea

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  • 1 Center for Ocean Research in Hong Kong and Macau, Department of Ocean Science and Department of Mathematics, Hong Kong University of Science and Technology, Hong Kong, China
  • | 2 State Key Laboratory of Internet of Things for Smart City and Department of Civil and Environmental Engineering, University of Macau, Macau, China
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Abstract

We investigated the mean kinetic energy (MKE) and eddy kinetic energy (EKE) in the South China Sea to illustrate the dynamics of the vertically rotating cyclonic–anticyclonic–cyclonic (CAC) circulation in the upper, middle, and deep layers. We found that strong MKE along the basin slope and the associated EKE arising from the vertical shear and stratification of the mean current characterize the circulation. In the upper layer, the external MKE input from the Kuroshio intrusion and wind forcing drive the cyclonic circulation, with the wind forcing providing most of the EKE. External forcing, however, does not directly provide the MKE and EKE of the CAC circulation in the semi-enclosed middle and deep layers, where the internal pressure work near Luzon Strait and the vertical buoyancy flux (VBF) in the southern basin and along the western slope maintain the MKE and EKE. The internal pressure work is formed by ageostrophic motion and pressure gradient field associated with circulation. The VBF is generated by vertical motion induced by the geostrophic cross-isobath transport along the slope where variable density field is maintained by the external flow and the internal mixing. The kinetic energy pathway in the CAC circulation indicates that the external forcing dominates upper-layer circulation and the coupling between internal and external dynamics is crucial for maintaining the circulation in the middle and deep layers. This study provides a new interpretation to the maintenance of CAC circulation from energy prospect.

© 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Jianping Gan, magan@ust.hk

Abstract

We investigated the mean kinetic energy (MKE) and eddy kinetic energy (EKE) in the South China Sea to illustrate the dynamics of the vertically rotating cyclonic–anticyclonic–cyclonic (CAC) circulation in the upper, middle, and deep layers. We found that strong MKE along the basin slope and the associated EKE arising from the vertical shear and stratification of the mean current characterize the circulation. In the upper layer, the external MKE input from the Kuroshio intrusion and wind forcing drive the cyclonic circulation, with the wind forcing providing most of the EKE. External forcing, however, does not directly provide the MKE and EKE of the CAC circulation in the semi-enclosed middle and deep layers, where the internal pressure work near Luzon Strait and the vertical buoyancy flux (VBF) in the southern basin and along the western slope maintain the MKE and EKE. The internal pressure work is formed by ageostrophic motion and pressure gradient field associated with circulation. The VBF is generated by vertical motion induced by the geostrophic cross-isobath transport along the slope where variable density field is maintained by the external flow and the internal mixing. The kinetic energy pathway in the CAC circulation indicates that the external forcing dominates upper-layer circulation and the coupling between internal and external dynamics is crucial for maintaining the circulation in the middle and deep layers. This study provides a new interpretation to the maintenance of CAC circulation from energy prospect.

© 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Jianping Gan, magan@ust.hk
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