Abstract
An array of three bottom-mounted ADCP moorings was deployed on the prevailing propagation path of strong internal tides for nearly 1 year across the continental slope in the northern South China Sea. These velocity measurements are used to study the intra-annual variability of diurnal and semidiurnal internal tidal energy in the region. A numerical model, the Luzon Strait Ocean Nowcast/Forecast System developed at the U.S. Naval Research Laboratory that covers the northern South China Sea and the Kuroshio, is used to interpret the observed variation of internal tidal energy on the Dongsha slope. Internal tides are generated primarily at the two submarine ridges in the Luzon Strait. At the western ridge generation site, the westward energy flux of the diurnal internal tide is sensitive to the stratification and isopycnal slope associated with the Kuroshio. The horizontal shear at the Kuroshio front does not modify the propagation path of either diurnal or semidiurnal tides because the relative vorticity of the Kuroshio in Luzon Strait is not strong enough to increase the effective inertial frequency to the intrinsic frequency of the internal tides. The variation of internal tidal energy on the continental slope and Dongsha plateau can be attributed to the variation in tidal beam propagation in the northern South China Sea.
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References
Chang MH, Lien RC, Tang TY, D’Asaro EA, Yang YJ (2006) Energy flux of nonlinear internal waves in northern South China Sea. Geophys Res Lett 33. doi:10.1029/2005GL025196
Duda TF, Rainville L (2008) Diurnal and semidiurnal internal tide energy flux at a continental slope in the South China Sea. J Geophys Res 113. doi:10.1029/2007JC004418
Duda TF, Lynch JF, Irish JD, Beardsley RC, Ramp SR, Chiu CS, Tang TY, Yang YJ (2004) Internal tide and nonlinear internal wave behavior at the continental slope in the northern South China Sea. IEEE J Ocean Eng 29:1105–1130
Farmer D, Li Q, Park JH (2009) Internal wave observations in the South China Sea: the role of rotation and non-linearity. Atmos Ocean 47:267–280
Gill AE (1982) Atmosphere-ocean dynamics. Academic Press, New York, p 662
Guo P, Fang WD, Liu CJ, Qiu FW (2012) Seasonal characteristics of internal tides on the continental shelf in the northern South China Sea. J Geophys Res 117. doi:10.1029/2011JC007215
Holloway PE, Pelinovsky E, Talipova T, Barnes B (1997) A nonlinear model of internal tide transformation on the Australian North West Shelf. J Phys Oceanogr 27:871–896
Jan S, Chern CS, Wang J, Chiou MD (2012) Generation and propagation of baroclinic tides modified by the Kuroshio in the Luzon Strait. J Geophys Res 117. doi:10.1029/2011JC007229
Jones WL (1967) Propagation of internal gravity waves in fluids with shear flow and rotation. J Fluid Mech 30:439–448
Klymak JM, Alford MH, Pinkel R, Lien R-C, Yang YJ, Tang TY (2011) The breaking and scattering of the internal tide on a continental slope. J Phys Oceanogr 41(5):926–945
Ko DS, Martin PJ, Rowley CD, Preller RH (2008) A real-time coastal ocean prediction experiment for MREA04. J Mar Syst 69(1–2):17–28
Kunze E (1985) Near-inertial wave propagation in geostrophic shear. J Phys Oceanogr 15(5):544–565
Kunze E, Sanford TB (1984) Observations of near-inertial waves in a front. J Phys Oceanogr 14(3):566–581
Lee CM, Eriksen CC (1997) Near-inertial internal wave interactions with mesoscale fronts: observations and models. J Geophys Res 102(C2):3237–3253
Lee IH, Wang YH, Yang Y, Wang DP (2012) Temporal variability of internal tides in the northeast South China Sea. J Geophys Res Oceans 117. doi:10.1029/2011JC007518
Mooers CNK (1975) Several effects of a baroclinic current on the three-dimensional propagation of inertial-internal waves. Geophys Fluid Dyn 6:277–284
Nash JD, Alford MH, Kunze E (2005) Estimating internal wave energy fluxes in the ocean. J Atmos Ocean Technol 22(10):1551–1570
Olbers DJ (1981) The propagation of internal waves in a geostrophic current. J Phys Oceanogr 11(9):1224–1233
Rainville L, Pinkel R (2004) Observations of energetic high-wavenumber internal waves in the Kuroshio. J Phys Oceanogr 34(7):1495–1505
Ramp SR, Tang TY, Duda TF, Lynch JF, Liu AK, Chiu CS, Bahr FL, Kim HR, Yang YJ (2004) Internal solitons in the northeastern South China Sea—part I: sources and deep water propagation. IEEE J Ocean Eng 29(4):1157–1181
Ramp SR, Yang YJ, Bahr FL (2010) Characterizing the nonlinear internal wave climate in the northeastern South China Sea. Nonlinear Proc Geophys 17(5):481–498
Ramp SR, Yang YJ, Reeder DB, Bahr FL (2012) Observations of a mode-2 nonlinear internal wave on the northern Heng-Chun Ridge south of Taiwan. J Geophys Res 117. doi:10.1029/2011JC007662
Reeder DB, Ma BB, Yang YJ (2011) Very large subaqueous sand dunes on the upper continental slope in the South China Sea generated by episodic, shoaling deep-water internal solitary waves. Mar Geol 279(1–4):12–18
Rudnick DL, Jan S, Centurioni L, Lee CM, Lien R-C, Wang J, Lee D-K, Tseng R-S, Kim YY, Chern C-S (2011) Seasonal and mesoscale variability of the Kuroshio near its origin. Oceanography 24(4):52–63
Scotti A, Beardsley RC, Butman B, Pineda J (2008) Shoaling of nonlinear internal waves in Massachusetts Bay. J Geophys Res 113. doi:10.1029/2008JC004726
Shaw PT, Ko DS, Chao SY (2009) Internal solitary waves induced by flow over a ridge: with applications to the northern South China Sea. J Geophys Res 114. doi:10.1029/2008JC005007
Teague WJ, Carron MJ, Hogan PJ (1990) A comparison between the generalized digital environmental-model and levitus climatologies. J Geophys Res 95:7167–7183
Vlasenko V, Stashchuk N, Hutter K (2005) Baroclinic tide: theoretical modeling and observational evidence. Cambridge University Press, Cambridge, p 351
Weller RA (1985) Near-surface velocity variability at inertial and subinertial frequencies in the vicinity of the California current. J Phys Oceanogr 15(4):372–385
Zhao ZX, Alford MH (2006) Source and propagation of internal solitary waves in the northeastern South China Sea. J Geophys Res 111. doi:10.1029/2006JC003644
Zhao Z, Klemas V, Zheng Q, and Yan X-H (2004) Remote sensing evidence for baroclinic tide origin of internal solitary waves in the northwestern South China Sea. Geophys Res Lett 31. doi:10.1029/2003GL019077
Acknowledgments
The authors thank the captain and crew of the R/V Ocean Researcher I and R/V Ocean Researcher III, and Mr. Wen-Hwa Her of the National Taiwan University for their skillful mooring operations. Discussions with Frank Henyey, Eric D’Asaro, and Eric Kunze are greatly appreciated. The comments from two anonymous reviewers helped greatly to improve the presentation of the manuscript. The experiment and analysis are supported by the U.S. Office of Naval Research grant N00014-09-1-0279. DSK is supported under grant N00014-05WX-2-0647.
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Ma, B.B., Lien, RC. & Ko, D.S. The variability of internal tides in the Northern South China Sea. J Oceanogr 69, 619–630 (2013). https://doi.org/10.1007/s10872-013-0198-0
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DOI: https://doi.org/10.1007/s10872-013-0198-0