scholarly journals Internal Solitary Waves in the Andaman Sea Revealed by Long-term Mooring Observations

2021 ◽  
Author(s):  
Yunchao Yang ◽  
Xiaodong Huang ◽  
Wei Zhao ◽  
Chun Zhou ◽  
Siwei Huang ◽  
...  
Keyword(s):  
Solitary Waves ◽  
Internal Tide ◽  
Equatorial Indian Ocean ◽  
Temporal Variations ◽  
Andaman Sea ◽  
Internal Solitary Waves ◽  
Release Mechanism ◽  
Annual Variations ◽  
Northern Portion

AbstractThe complex behaviors of internal solitary waves (ISWs) in the Andaman Sea were revealed using data collected over nearly 22-month-long observation period completed by two moorings. Emanating from the submarine ridges northwest of Sumatra Island and south of Car Nicobar, two types of ISWs, referred to as S- and C-ISWs, respectively, were identified in the measurements, and S-ISWs were generally found to be stronger than C-ISWs. The observed S- and C-ISWs frequently appeared as multi-wave packets, accounting for 87% and 43% of their observed episodes, respectively. The simultaneous measurements collected by the two moorings featured evident variability along the S-ISW crests, with the average wave amplitude in the northern portion being 36% larger than that in the southern portion. The analyses of the arrival times revealed that the S-ISWs in the northern portion occurred more frequently and arrived more irregularly than those in the southern portion. Moreover, the temporal variability of ISWs drastically differed on monthly and seasonal time scales, characterized by relatively stronger S-ISWs in spring and autumn. Over interannual time scale, the temporal variations in ISWs were generally subtle. The monthly-to-annual variations of ISWs could be mostly explained by the variability in stratification, which could be modulated by the monsoons, the winds in equatorial Indian Ocean and the mesoscale eddies in Andaman Sea. From careful analyses preformed based on the long-term measurements, we argued that the observed ISWs were likely generated via internal tide release mechanism and their generation processes were obviously modulated by background circulations.

scholarly journals Internal Solitary Waves in the Andaman Sea: New Insights from SAR Imagery

2018 ◽  
Vol 10 (6) ◽  
pp. 861 ◽  
Author(s):  
Jorge Magalhaes ◽  
José da Silva
Keyword(s):  
Solitary Waves ◽  
Andaman Sea ◽  
Internal Solitary Waves ◽  
Sar Imagery

Internal wave energetics modulated by Indonesian Throughflow at Lombok Strait

2020 ◽  
Author(s):  
Zhenhua Xu
Keyword(s):  
Solitary Waves ◽  
Southern Oscillation ◽  
Internal Tide ◽  
Internal Tides ◽  
Internal Solitary Waves ◽  
Indonesian Throughflow ◽  
Indonesian Seas ◽  
The North ◽  
Tide Propagation ◽  
Seasonal And Interannual Variations

<p>The interaction between the energetic internal waves in the Indonesian Seas and the Indonesian Throughflow (ITF) is not well known. Here we conduct a series of high-resolution numerical simulations surrounding the Lombok Strait, Indonesia, which is an important exit channel for the ITF, to explore the influences of the ITF on the spatiotemporal variations of M2 internal tides and associated internal solitary waves from the Strait. The ITF enhances the north-south asymmetry of internal tide propagation from the Lombok Strait, thus resulting in the spatial variability of northward and southward internal solitary waves. Interannual variability of internal tide generation and dissipation are due to ITF and air-sea freshwaterflux induced stratification variations associated with El Niño-Southern Oscillation. The local dissipation efficiency q exhibits substantial seasonal and interannual variations, which may provide effective feedback to the climate processes in the low-latitude equatorial oceans.</p>

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

2021 ◽  
Author(s):  
Yujun Yu ◽  
Shuya Wang ◽  
Xu Chen
Keyword(s):  
Solitary Waves ◽  
Influence Factors ◽  
Internal Tides ◽  
Andaman Sea ◽  
Internal Solitary Waves ◽  
Minor Effect ◽  
Nicobar Island ◽  
Tidal Forcing ◽  
Topographic Features ◽  
Low Froude Number

<p>Internal Solitary Waves (ISW) are ubiquitous in the Andaman Sea as revealed by Synthetic Aperture Radar (SAR) images, but their generation mechanism and corresponding influence factors remain unknown. Based on a non-hydrostatic two-dimensional model, the generation of ISW across the channel between the Batti Malv Island and the Car Nicobar Island is investigated. Influences of the topography characteristics, seasonal stratification and tidal forcing are analyzed with a series of sensitivity runs. The simulated results indicate that no apparent ISW appear near the ridge because of small tidal excursion and low Froude number. Instead, they are evolved from the disintegrated internal tides which gradually steepen due to nonlinearity during propagation. East-west asymmetry of ISWs is revealed, which can be attributed to different topographic features on the two sides of the ridge. Two sills on the east side of the ridge further complicate the generation of eastward-propagating internal tides, resulting in the enhancement of ISWs in the Andaman Sea. Seasonally varying stratification has minor effect on the generation and evolution of ISWs. In addition, generation of ISW is mainly contributed by semidiurnal tidal forcing, while diurnal forcing only generates linear internal tides.</p>

scholarly journals Long-term evolution of strongly nonlinear internal solitary waves in a rotating channel

2009 ◽  
Vol 16 (5) ◽  
pp. 587-598 ◽  
Author(s):  
J. C. Sánchez-Garrido ◽  
V. Vlasenko
Keyword(s):  
Solitary Waves ◽  
Nonlinear Effects ◽  
Kelvin Waves ◽  
Internal Solitary Waves ◽  
Kelvin Wave ◽  
Weakly Nonlinear ◽  
Strongly Nonlinear ◽  
Petviashvili Equation ◽  
Rotating Channel

Abstract. The evolution of internal solitary waves (ISWs) propagating in a rotating channel is studied numerically in the framework of a fully-nonlinear, nonhydrostatic numerical model. The aim of modelling efforts was the investigation of strongly-nonlinear effects, which are beyond the applicability of weakly nonlinear theories. Results reveal that small-amplitude waves and sufficiently strong ISWs evolve differently under the action of rotation. At the first stage of evolution an initially two-dimensional ISW transforms according to the scenario described by the rotation modified Kadomtsev-Petviashvili equation, namely, it starts to evolve into a Kelvin wave (with exponential decay of the wave amplitude across the channel) with front curved backwards. This transition is accompanied by a permanent radiation of secondary Poincaré waves attached to the leading wave. However, in a strongly-nonlinear limit not all the energy is transmitted to secondary radiated waves. Part of it returns to the leading wave as a result of nonlinear interactions with secondary Kelvin waves generated in the course of time. This leads to the formation of a slowly attenuating quasi-stationary system of leading Kelvin waves, capable of propagating for several hundreds hours as a localized wave packet.

scholarly journals Modelling internal solitary waves on the Australian North West Shelf

2006 ◽  
Vol 57 (3) ◽  
pp. 265 ◽  
Author(s):  
Roger Grimshaw ◽  
Efim Pelinovsky ◽  
Yury Stepanyants ◽  
Tatiana Talipova
Keyword(s):  
Solitary Waves ◽  
Vries Equation ◽  
Internal Tide ◽  
Internal Solitary Waves ◽  
Linear Wave ◽  
North West ◽  
Non Linear ◽  
Wave Path ◽  
Simulation Results ◽  
Synergetic Action

The transformation of the non-linear internal tide and the consequent development of internal solitary waves on the Australian North West Shelf is studied numerically in the framework of the generalised rotation-modified Korteweg–de Vries equation. This model contains both non-linearity (quadratic and cubic), the Coriolis effect, depth variation and horizontal variability of the density stratification. The simulation results demonstrate that a wide variety of non-linear wave shapes can be explained by the synergetic action of non-linearity and the variability of the hydrology along the wave path.

Statistics of Internal Tide Bores and Internal Solitary Waves Observed on the Inner Continental Shelf off Point Sal, California

2018 ◽  
Vol 48 (1) ◽  
pp. 123-143 ◽  
Author(s):  
John A. Colosi ◽  
Nirnimesh Kumar ◽  
Sutara H. Suanda ◽  
Tucker M. Freismuth ◽  
Jamie H. MacMahan
Keyword(s):  
Continental Shelf ◽  
Energy Flux ◽  
Solitary Waves ◽  
Internal Tide ◽  
Propagation Loss ◽  
Internal Solitary Waves ◽  
Time Behavior ◽  
Time Duration ◽  
Match Filter ◽  
Inner Continental Shelf

AbstractMoored observations of temperature and current were collected on the inner continental shelf off Point Sal, California, between 9 June and 8 August 2015. The measurements consist of 10 moorings in total: 4 moorings each on the 50- and 30-m isobaths covering a 10-km along-shelf distance and an across-shelf section of moorings on the 50-, 40-, 30-, and 20-m isobaths covering a 5-km distance. Energetic, highly variable, and strongly dissipating transient wave events termed internal tide bores and internal solitary waves (ISWs) dominate the records. Simple models of the bore and ISW space–time behavior are implemented as a temperature match filter to detect events and estimate wave packet parameters as a function of time and mooring position. Wave-derived quantities include 1) group speed and direction; 2) time of arrival, time duration, vertical displacement amplitude, and waves per day; and 3) energy density, energy flux, and propagation loss. In total, over 1000 bore events and over 9000 ISW events were detected providing well-sampled statistical distributions. Statistics of the waves are rather insensitive to position along shelf but change markedly in the across-shelf direction. Two compelling results are 1) that the probability density functions for bore and ISW energy flux are nearly exponential, suggesting the importance of interference and 2) that wave propagation loss is proportional to energy flux, thus giving an exponential decay of energy flux toward shore with an e-folding scale of 2–2.4 km and average dissipation rates for bores and ISWs of 144 and 1.5 W m−1, respectively.

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.

Sign in / Sign up

Export Citation Format

Share Document