Very large subaqueous sand dunes on the upper continental slope in the South China Sea generated by episodic, shoaling deep-water internal solitary waves

Reeder, D. Benjamin; Ma, Barry; Yang, Yiing Jang

doi:10.1016/j.margeo.2010.10.009

Cited by 149 publications

(140 citation statements)

References 65 publications

Supporting

Mentioning

135

Contrasting

Order By: Relevance

“…In deep water the near bottom currents are much weaker, which would reduce the effects of the bottom boundary layer beneath the shoaling waves. Observations of sand dunes in the northern South China Sea reported by Reeder et al (2011) at depths between 160 and 600 m suggest that bottom boundary layer processes could be important at depths greater than 200 m. Our simulations suggest that the presence of a turbulent bottom boundary layer beneath the waves could significantly affect shoaling solitary waves in water depths shallower than 200 m; however, these results are quite sensitive to the eddy viscosity. A more detailed investigation is needed.…”

Section: Effects Of Viscosity and Boundary Layer Separationmentioning

confidence: 59%

See 1 more Smart Citation

Two-dimensional numerical simulations of shoaling internal solitary waves at the ASIAEX site in the South China Sea

Lamb

Warn-Varnas

2015

Nonlin. Processes Geophys.

View full text Add to dashboard Cite

Abstract. The interaction of barotropic tides with LuzonStrait topography generates some of the world's largest internal solitary waves which eventually shoal and dissipate on the western side of the northern South China Sea. Twodimensional numerical simulations of the shoaling of a single internal solitary wave at the site of the Asian Seas International Acoustic Experiment (ASIAEX) have been undertaken in order to investigate the sensitivity of the shoaling process to the stratification and the underlying bathymetry and to explore the influence of rotation. The bulk of the simulations are inviscid; however, exploratory simulations using a vertical eddy-viscosity confined to a near bottom layer, along with a no-slip boundary condition, suggest that viscous effects may become important in water shallower than about 200 m. A shoaling solitary wave fissions into several waves. At depths of 200-300 m the front of the leading waves become nearly parallel to the bottom and develop a very steep back as has been observed. The leading waves are followed by waves of elevation (pedestals) that are conjugate to the waves of depression ahead and behind them. Horizontal resolutions of at least 50 m are required to simulate these well. Wave breaking was found to occur behind the second or third of the leading solitary waves, never at the back of the leading wave. Comparisons of the shoaling of waves started at depths of 1000 and 3000 m show significant differences and the shoaling waves can be significantly non-adiabatic even at depths greater than 2000 m. When waves reach a depth of 200 m, their amplitudes can be more than 50 % larger than the largest possible solitary wave at that depth. The shoaling behaviour is sensitive to the presence of small-scale features in the bathymetry: a 200 m high bump at 700 m depth can result in the generation of many mode-two waves and of higher mode waves. Sensitivity to the stratification is considered by using three stratifications based on summer observations. They primarily differ in the depth of the thermocline. The generation of mode-two waves and the behaviour of the waves in shallow water is sensitive to this depth. Rotation affects the shoaling waves by reducing the amplitude of the leading waves via the radiation of long trailing inertiagravity waves. The nonlinear-dispersive evolution of these inertia-gravity waves results in the formation of secondary mode-one wave packets.

show abstract

Section: Effects Of Viscosity and Boundary Layer Separationmentioning

confidence: 59%

“…The large internal solitary waves that shoal onto the Chinese continental shelf are highly energetic features that have implications for biological productivity and sediment transport (Wang et al, 2007;Reeder et al, 2011). St.…”

Section: K G Lamb and A Warn-varnas: Shoaling Internal Solitary Wavesmentioning

confidence: 99%

Two-dimensional numerical simulations of shoaling internal solitary waves at the ASIAEX site in the South China Sea

Lamb

Warn-Varnas

2015

Nonlin. Processes Geophys.

View full text Add to dashboard Cite

show abstract

“…Nonlinear internal waves [4,38], giant bottom waves [23], or large surface swell waves [27] are good examples for this. For the case of internal waves, low frequency acoustic propagation has been traditionally divided into four regimes [39] depending on the horizontal grazing angle.…”

Section: Sharp Interface Approximationmentioning

confidence: 99%

“…He concludes that sand waves are more regular and have longer crest continuity than megaripples. Reeder et al [23] has recently observed large sand waves on the continental slope of the Northern South China Sea that have crest to crest wavelengths exceeding 350 meters and amplitude exceeding 16 meters. He discovered that these waves were generated by strong interaction of nonlinear internal waves with the continental slope.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional acoustic propagation through shallow water internal, surface gravity and bottom sediment waves

Shmelev¹

2011

View full text Add to dashboard Cite

This thesis describes the physics of fully three-dimensional low frequency acoustic interaction with internal waves, bottom sediment waves and surface swell waves that are often observed in shallow waters and on continental slopes. A simple idealized model of the ocean waveguide is used to analytically study the properties of acoustic normal modes and their perturbations due to waves of each type. The combined approach of a semi-quantitative study based on the geometrical acoustics approximation and on fully three-dimensional coupled mode numerical modeling is used to examine the azimuthal dependence of sound wave horizontal reflection from, transmission through and ducting between straight parallel waves of each type. The impact of the natural crossings of nonlinear internal waves on horizontally ducted sound energy is studied theoretically and modeled numerically using a three-dimensional parabolic equation acoustic propagation code. A realistic sea surface elevation is synthesized from the directional spectrum of long swells and used for three-dimensional numerical modeling of acoustic propagation. As a result, considerable normal mode amplitude scintillations were observed and shown to be strongly dependent on horizontal azimuth, range and mode number. Full field numerical modeling of low frequency sound propagation through large sand waves located on a sloped bottom was performed using the high resolution bathymetry of the mouth of San Francisco Bay. Very strong acoustic ducting is shown to steer acoustic energy beams along the sand wave's curved crests.

show abstract

“…Large IWs are highly significant for sediment resuspension and transport (Bogucki and Redekopp, 1999;Stastna and Lamb, 2008;Reeder et al, 2011) and for the biology on the continental shelf (Sandstrom and Elliott, 1984). The currents forced by large or breaking IWs cause powerful forces on marine platforms and submersibles.…”

Section: Introductionmentioning

confidence: 99%

Propagation regimes of interfacial solitary waves in a three-layer fluid

Kurkina¹,

Kurkin²,

Rouvinskaya³

et al. 2015

Nonlin. Processes Geophys.

View full text Add to dashboard Cite

Abstract. Long weakly nonlinear finite-amplitude internal waves in a fluid consisting of three inviscid layers of arbitrary thickness and constant densities (stable configuration, Boussinesq approximation) bounded by a horizontal rigid bottom from below and by a rigid lid at the surface are described up to the second order of perturbation theory in small parameters of nonlinearity and dispersion. First, a pair of alternatives of appropriate KdV-type equations with the coefficients depending on the parameters of the fluid (layer positions and thickness, density jumps) are derived for the displacements of both modes of internal waves and for each interface between the layers. These equations are integrable for a very limited set of coefficients and do not allow for proper description of several near-critical cases when certain coefficients vanish. A more specific equation allowing for a variety of solitonic solutions and capable of resolving most near-critical situations is derived by means of the introduction of another small parameter that describes the properties of the medium and rescaling of the ratio of small parameters. This procedure leads to a pair of implicitly interrelated alternatives of Gardner equations (KdV-type equations with combined nonlinearity) for the two interfaces. We present a detailed analysis of the relationships for the solutions for the disturbances at both interfaces and various regimes of the appearance and propagation properties of soliton solutions to these equations depending on the combinations of the parameters of the fluid. It is shown that both the quadratic and the cubic nonlinear terms vanish for several realistic configurations of such a fluid.

show abstract

Very large subaqueous sand dunes on the upper continental slope in the South China Sea generated by episodic, shoaling deep-water internal solitary waves

Cited by 149 publications

References 65 publications

Two-dimensional numerical simulations of shoaling internal solitary waves at the ASIAEX site in the South China Sea

Two-dimensional numerical simulations of shoaling internal solitary waves at the ASIAEX site in the South China Sea

Three-dimensional acoustic propagation through shallow water internal, surface gravity and bottom sediment waves

Propagation regimes of interfacial solitary waves in a three-layer fluid

Contact Info

Product

Resources

About