Large-amplitude internal waves observed off the northwest coast of Sumatra

Perry, Richard; Schimke, Gerald R.

doi:10.1029/jz070i010p02319

Cited by 84 publications

(46 citation statements)

References 2 publications

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“…The density differences within the fluid are smaller than at the surface between water and air; hence, the returning forces are weaker, and the wave periods are longer than the periods of surface waves. In oceanic conditions, the amplitudes v of waves can be as large as several tens or even hundreds of meters as reported in early publications (Bockel 1962;Perry and Schimke 1965;Niiler 1968;Osborne and Burch 1980).…”

Section: Prefacementioning

confidence: 90%

Oceanic Internal Tides: Observations, Analysis and Modeling

Morozov

2018

116

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Section: Prefacementioning

confidence: 90%

Oceanic Internal Tides: Observations, Analysis and Modeling

Morozov

2018

116

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“…This means that F can be analytically integrated provided that Q is previously known, and for that purpose the components of the barotropic velocity vector were taken from the 1/12° resolution OTIS model (Oregon state university Tidal Inversion Software, developed in [23] 4 ), of which the M 2 and S 2 tidal constituents (periods of 12.42 and 12.00 h, respectively) are the most important of the barotropic tide in this study region. The bathymetry data is part of the one minute global bathymetry from Smith and Sandwell [24] , and N(z) is assumed to be spatially constant in the horizontal.…”

Section: Methodsmentioning

confidence: 99%

“…Perry and Schimke [4] were the first to conduct oceanographic measurements of these waves from a ship, confirming that these bands of choppy water in the Andaman Sea were associated with solitons, or Internal Solitary Waves (ISWs). Later, Osborne and Burch [1] analyzed oceanographic data collected by the Exxon Production Research Company in the southern Andaman Sea with the aim to assess the impact of underwater currents associated with oceanic internal waves on drilling operations carried out from a drill ship.…”

Section: Introductionmentioning

confidence: 99%

Internal solitons in the Andaman Sea: a new look at an old problem

Silva¹,

Magalhaes²

2016

SPIE Proceedings

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When Osborne and Burch [1] reported their observations of large-amplitude, long internal waves in the Andaman Sea that conform with theoretical results from the physics of nonlinear waves, a new research field on ocean waves was immediately set out. They described their findings in the frame of shallow-water solitary waves governed by the K-dV equation, which occur because of a balance between nonlinear cohesive and linear dispersive forces in a fluid. It was concluded that the internal waves in the Andaman Sea were solitons and that they evolved either from an initial waveform (over approximately constant water depth) or by a fission process (over variable water depth). Since then, there has been a great deal of progress in our understanding of Internal Solitary Waves (ISWs), or solitons in the ocean, particularly making use of satellite Synthetic Aperture Radar (SAR) systems. While two layer models such as those used by Osborne and Burch [1] allow for propagation of fundamental mode (i.e. mode-1) ISWs, continuous stratification permits the existence of higher mode internal waves. It happens that the Andaman Sea stratification is characterized by two (or more) maxima in the vertical profile of the buoyancy frequency N(z), i.e. a double pycnocline, hence prone to the existence of mode-2 (or higher) internal waves. In this paper we report solitary-like internal waves with mode-2 vertical structure co-existing with the large well know mode-1 solitons. The mode-2 waves are identified in satellite SAR images (e.g. TerraSAR-X, Envisat, etc.) because of their distinct surface signature. While the SAR image intensity of mode-1 waves is characterized by bright, enhanced backscatter preceding dark reduced backscatter along the nonlinear internal wave propagation direction (in agreement with Alpers, 1985 [2] ), for mode-2 solitary wave structures, the polarity of the SAR signature is reversed and thus a dark reduced backscatter crest precedes a bright, enhanced backscatter feature in the propagation direction of the wave. The polarity of these mode-2 signatures changes because the location of the surface convergent and divergent zones is reversed in relation to mode-1 ISWs. Mode-2 ISWs are identified in many locations of the Andaman Sea, but here we focus on ISWs along the Ten Degree Channel which occur along-side large mode-1 ISWs. We discuss possible generation locations and mechanisms for both mode-1 and mode-2 ISWs along this stretch of the Andaman Sea, recurring to modeling of the ray pathways of internal tidal energy propagation, and the P. G. Baines [3] barotropic body force, which drives the generation of internal tides near the shallow water areas between the Andaman and Nicobar Islands. We consider three possible explanations for mode-2 solitary wave generation in the Andaman Sea: (1) impingement of an internal tidal beam on the pycnocline, itself emanating from critical bathymetry; (2) nonlinear disintegration of internal tide modes; (3) the lee wave forming mechanism to the west of a ridge during westw...

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“…These features were especially notable below regions of elevated chlorophyll feature. The internal wave climate of the BoB is poorly characterized, apart from relatively sparse measurements of the semidiurnal tides and high-frequency waves obtained over the past several decades (e.g., Wijeratne et al 2010;Jackson 2007;Antony et al 1985;Osborne and Burch 1980;Perry and Schimke 1965). ASIRI observations provide new insights into the internal wavefield through the NRL mooring array (Fig.…”

Section: Modeling Program Continuedmentioning

confidence: 99%

ASIRI: An Ocean–Atmosphere Initiative for Bay of Bengal

Wijesekera

Shroyer

Tandon

et al. 2016

Bulletin of the American Meteorological Society

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Air–Sea Interactions in the Northern Indian Ocean (ASIRI) is an international research effort (2013–17) aimed at understanding and quantifying coupled atmosphere–ocean dynamics of the Bay of Bengal (BoB) with relevance to Indian Ocean monsoons. Working collaboratively, more than 20 research institutions are acquiring field observations coupled with operational and high-resolution models to address scientific issues that have stymied the monsoon predictability. ASIRI combines new and mature observational technologies to resolve submesoscale to regional-scale currents and hydrophysical fields. These data reveal BoB’s sharp frontal features, submesoscale variability, low-salinity lenses and filaments, and shallow mixed layers, with relatively weak turbulent mixing. Observed physical features include energetic high-frequency internal waves in the southern BoB, energetic mesoscale and submesoscale features including an intrathermocline eddy in the central BoB, and a high-resolution view of the exchange along the periphery of Sri Lanka, which includes the 100-km-wide East India Coastal Current (EICC) carrying low-salinity water out of the BoB and an adjacent, broad northward flow (∼300 km wide) that carries high-salinity water into BoB during the northeast monsoon. Atmospheric boundary layer (ABL) observations during the decaying phase of the Madden–Julian oscillation (MJO) permit the study of multiscale atmospheric processes associated with non-MJO phenomena and their impacts on the marine boundary layer. Underway analyses that integrate observations and numerical simulations shed light on how air–sea interactions control the ABL and upper-ocean processes.

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Large-amplitude internal waves observed off the northwest coast of Sumatra

Cited by 84 publications

References 2 publications

Oceanic Internal Tides: Observations, Analysis and Modeling

Oceanic Internal Tides: Observations, Analysis and Modeling

Internal solitons in the Andaman Sea: a new look at an old problem

ASIRI: An Ocean–Atmosphere Initiative for Bay of Bengal

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