On the dependence of radar signatures of oceanic internal solitary waves on wind conditions and internal wave parameters

1998 ◽  
Author(s):  
P. Brandt ◽  
R. Romeiser ◽  
A. Rubino
Keyword(s):  
Internal Wave ◽  
Solitary Waves ◽  
Internal Solitary Waves ◽  
Wave Parameters ◽  
Radar Signatures

scholarly journals An Empirical Model for Estimating the Geographic Location of Nonlinear Internal Solitary Waves

2009 ◽  
Vol 26 (10) ◽  
pp. 2243-2255 ◽  
Author(s):  
Christopher R. Jackson
Keyword(s):  
Internal Wave ◽  
Solitary Waves ◽  
Phase Speed ◽  
Geographic Location ◽  
Propagation Path ◽  
Internal Solitary Waves ◽  
Propagation Time ◽  
Model Function ◽  
New Approach ◽  
Parameterized Model

Abstract This paper describes the development and performance of a new approach for estimating the geographic location of high-frequency nonlinear internal waves. The approach makes use of the internal wave signatures recorded in satellite imagery to determine the parameters of a model function that relates the internal wave phase speed to depth. The phase speed map produced by the parameterized model function establishes a propagation time and propagation path between an origin and any location in the region of interest. Contours of propagation time represent the internal wave locations for a particular time since generation. The parameters of the model function are found by minimizing the difference between the calculated propagation times and the observed propagation times. This approach is applied to the internal solitary waves observed in the northern portion of the South China Sea west of the Luzon Strait. Propagation time estimates based on this new approach have errors of ±1.32 h (1σ) for depths greater than 1000 m and ±2.55 h (1σ) for all depths over which the waves are observed.

The limiting form of internal waves

1984 ◽  
Vol 394 (1807) ◽  
pp. 329-344 ◽  
Keyword(s):  
Free Surface ◽  
Internal Wave ◽  
Internal Waves ◽  
Solitary Waves ◽  
The Other ◽  
Stokes Wave ◽  
Internal Solitary Waves ◽  
Two Dimensional ◽  
Extreme Form ◽  
Eddy Formation

The bifurcation of two-dimensional internal solitary waves in a perfect density stratified fluid between horizontal walls under gravity is studied near to a point of incipient eddy formation. It is shown that eddies do not attach to the walls. Moreover, along the bifurcating branch there is always a flow with a singular cusped streamline before the formation of eddies. This flow with the cusped streamline is an example of what we call an internal wave of limiting form, by analogy with the Stokes wave of extreme form in the free surface problem. Two examples are given where the primary density stratification ensures the existence of a limiting wave of depression in one case, and of elevation in the other.

Internal Wave Generation in Tropical Upwelling Regions: the Angolan and Peruvian Shelves

2020 ◽  
Author(s):  
Kevin Lamb ◽  
Peter Brandt ◽  
Marcus Dengler
Keyword(s):  
Internal Wave ◽  
Solitary Waves ◽  
High Frequency ◽  
Wave Generation ◽  
Internal Solitary Waves ◽  
Small Scale ◽  
Tropical Atlantic ◽  
Near Surface ◽  
High Productivity ◽  
Internal Wave Generation

<p>The Angolan and Peruvian shelves are located in upwelling regions along the eastern boundaries of the tropical Atlantic and Pacific Oceans. They are sites of important fisheries supported by high productivity which is driven by fluxes of nutrients from deep to near surface water along the coast. Mixing associated with internal waves is believed to play a role in this process. Recent field observations have shown the presence of an active internal wave field that includes internal solitary waves. In this talk results of high-resolution two-dimensional simulations of internal wave generation by tide-topography interactions on the Angolan and Peruvian shelves are presented. The simulations show the generation of internal wave beams at near-critical slopes and the generation of high-frequency internal solitary waves. The high-frequency IW spectrum is enhanced when small scale bathymetric ripples are included. Wave generation during winter and summer stratifications will be compared.</p>

scholarly journals On the Generation and Evolution of Internal Solitary Waves in the Andaman Sea

2021 ◽  
Author(s):  
Yujun Yu ◽  
Jinhu Wang ◽  
Shuya Wang ◽  
Qun Li ◽  
Xu Chen ◽  
...  
Keyword(s):  
Internal Wave ◽  
Solitary Waves ◽  
Spring Tide ◽  
Internal Tides ◽  
Andaman Sea ◽  
Internal Solitary Waves ◽  
Minor Effect ◽  
Nicobar Island ◽  
Topographic Characteristics ◽  
East West

Abstract. Internal solitary waves (ISWs) are ubiquitous in the Andaman Sea, as revealed by synthetic aperture radar (SAR) images, but their generation mechanisms and corresponding influencing factors remain unknown. Based on a nonhydrostatic two-dimensional model, the generation of ISW packets along a transect of a channel lying between Batti Malv Island and Car Nicobar Island is investigated. Additionally, the influences of topographic characteristics, seasonal stratification variables and tidal forcings are analysed through a series of sensitivity runs. The simulated results indicate that bidirectional rank-ordered ISW packets are generated by the nonlinear steepening of internal tides. An east-west ISW asymmetry is observed, which is attributed to distinct topographic characteristics. The surrounding sills are also capable of generating internal wave beams, which modulate the intensity of ISWs. However, the topographic structure of the west flank of the ridge mainly contributes to the suppression of westward ISWs, which decrease the modulating effect of internal wave beams. During spring tide, the generation of ISWs is enhanced. Under neap tide, ISWs are weak, and the east-west ISW asymmetry is less obvious. Moreover, seasonally varied stratification only has a minor effect on the generation and evolution of ISWs.

Simulation of the Transformation of Internal Solitary Waves on Oceanic Shelves

2004 ◽  
Vol 34 (12) ◽  
pp. 2774-2791 ◽  
Author(s):  
Roger Grimshaw ◽  
Efim Pelinovsky ◽  
Tatiana Talipova ◽  
Audrey Kurkin
Keyword(s):  
Solitary Wave ◽  
Solitary Waves ◽  
Variable Coefficient ◽  
Asymptotic Theory ◽  
Vries Equation ◽  
Internal Solitary Waves ◽  
Variable Depth ◽  
North West ◽  
Wave Parameters ◽  
De Vries

Abstract Internal solitary waves transform as they propagate shoreward over the continental shelf into the coastal zone, from a combination of the horizontal variability of the oceanic hydrology (density and current stratification) and the variable depth. If this background environment varies sufficiently slowly in comparison with an individual solitary wave, then that wave possesses a soliton-like form with varying amplitude and phase. This stage is studied in detail in the framework of the variable-coefficient extended Korteweg–de Vries equation where the variation of the solitary wave parameters can be described analytically through an asymptotic description as a slowly varying solitary wave. Direct numerical simulation of the variable-coefficient extended Korteweg–de Vries equation is performed for several oceanic shelves (North West shelf of Australia, Malin shelf edge, and Arctic shelf) to demonstrate the applicability of the asymptotic theory. It is shown that the solitary wave may maintain its soliton-like form for large distances (up to 100 km), and this fact helps to explain why internal solitons are widely observed in the world's oceans. In some cases the background stratification contains critical points (where the coefficients of the nonlinear terms in the extended Korteweg–de Vries equation change sign), or does not vary sufficiently slowly; in such cases the solitary wave deforms into a group of secondary waves. This stage is studied numerically.

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