scholarly journals Internal solitary waves in the Northwest Sumatra Sea-Indonesia: from observation and modeling

2021 ◽  
Vol 944 (1) ◽  
pp. 012056
Author(s):  
I A Prasetya ◽  
A S Atmadipoera ◽  
S Budhiman ◽  
U C Nugroho
Keyword(s):  
Solitary Waves ◽  
High Tide ◽  
Tidal Currents ◽  
Internal Tides ◽  
Sea Surface ◽  
Radar Signal ◽  
Internal Solitary Waves ◽  
Tidal Waves ◽  
Submarine Ridge ◽  
Lee Waves

Abstract >The southern Andaman waters has been well known as one of the strongest generating and propagating area of internal solitary waves (ISWs), generated by semidiurnal barotropic tidal currents that impinge submarine ridge offshore western Weh. This study aims to investigate sea surface features of internal tides and tidal current around the submarine ridge and adjacent Weh-Aceh waters, derived from satellite imagery datasets (January-May 2018) and CROCO model-output datasets. The results show that sea surface signatures of ISWs are characterized by a strong radar signal backscattering of a dense ripple package in the generating area and two groups of ISWs arch in the propagating area, where the distance of the package groups and wavelengths vary 60-80 km and 9-163 km, respectively. Observed ISWs in March 2018 was 31. The satellite and model datasets suggest that generating area of internal waves is confined over the Breuh ridge. Here, the very strong semidiurnal (M2) barotropic tidal currents of 0.5-5.0 m/s are observed. During high-tide, amplified barotropic tidal currents acrossing the ridge flow partly southeastward into the Weh-Breuh passage. The model suggests that generating internal tidal waves over the ridge are manifested by strong vertical perturbation of isopycnal and current stratifications in the Lee-waves area.

scholarly journals Generation of Internal Solitary Waves by Lateral Circulation in a Stratified Estuary

2017 ◽  
Vol 47 (7) ◽  
pp. 1789-1797 ◽  
Author(s):  
Xiaohui Xie ◽  
Ming Li ◽  
Malcolm Scully ◽  
William C. Boicourt
Keyword(s):  
Solitary Waves ◽  
Tidal Flow ◽  
Tidal Currents ◽  
Internal Solitary Waves ◽  
Deep Channel ◽  
Mode 2 ◽  
Lee Wave ◽  
Salinity Data ◽  
Lateral Circulation ◽  
Stratified Estuary

AbstractInternal solitary waves are commonly observed in the coastal ocean where they are known to contribute to mass transport and turbulent mixing. While these waves are often generated by cross-isobath barotropic tidal currents, novel observations are presented suggesting that internal solitary waves result from along-isobath tidal flows over channel-shoal bathymetry. Mooring and ship-based velocity, temperature, and salinity data were collected over a cross-channel section in a stratified estuary. The data show that Ekman forcing on along-channel tidal currents drives lateral circulation, which interacts with the stratified water over the deep channel to generate a supercritical mode-2 internal lee wave. This lee wave propagates onto the shallow shoal and evolves into a group of internal solitary waves of elevation due to nonlinear steepening. These observations highlight the potential importance of three-dimensionality on the conversion of tidal flow to internal waves in the rotating ocean.

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>

Effects of tidal currents on nonlinear internal solitary waves in the South China Sea

2013 ◽  
Vol 12 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Zhisong Fan ◽  
Xingang Shi ◽  
Antony K. Liu ◽  
Hailong Liu ◽  
Peiliang Li
Keyword(s):  
South China Sea ◽  
Solitary Waves ◽  
South China ◽  
Tidal Currents ◽  
The South China Sea ◽  
Internal Solitary Waves ◽  
The South ◽  
China Sea

scholarly journals Quantifying Tidal Fluctuations in Remote Sensing Infrared SST Observations

2019 ◽  
Vol 11 (19) ◽  
pp. 2313 ◽  
Author(s):  
Cristina González-Haro ◽  
Aurélien Ponte ◽  
Emmanuelle Autret
Keyword(s):  
Scalar Product ◽  
Tidal Currents ◽  
Internal Tides ◽  
Sea Surface ◽  
Spatial Structures ◽  
Tidal Flows ◽  
Geophysical Processes ◽  
Infrared Sst ◽  
Sst Fronts ◽  
Observing Systems

The expected amplitude of fixed-point sea surface temperature (SST) fluctuations induced by barotropic and baroclinic tidal flows is estimated from tidal current atlases and SST observations. The fluctuations considered are the result of the advection of pre-existing SST fronts by tidal currents. They are thus confined to front locations and exhibit fine-scale spatial structures. The amplitude of these tidally induced SST fluctuations is proportional to the scalar product of SST frontal gradients and tidal currents. Regional and global estimations of these expected amplitudes are presented. We predict barotropic tidal motions produce SST fluctuations that may reach amplitudes of 0.3 K. Baroclinic (internal) tides produce SST fluctuations that may reach values that are weaker than 0.1 K. The amplitudes and the detectability of tidally induced fluctuations of SST are discussed in the light of expected SST fluctuations due to other geophysical processes and instrumental (pixel) noise. We conclude that actual observations of tidally induced SST fluctuations are a challenge with present-day observing systems.

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>

Three dimensional simulation on the generation and propagation of internal tides and solitary waves northeast of Taiwan Island

2021 ◽  
Author(s):  
Wenjia Min ◽  
Zhenhua Xu ◽  
Qun Li ◽  
Peiwen Zhang ◽  
Baoshu Yin
Keyword(s):  
Continental Slope ◽  
Solitary Waves ◽  
Okinawa Trough ◽  
Satellite Image ◽  
Three Dimensional ◽  
Internal Tides ◽  
Internal Solitary Waves ◽  
Strong Mixing ◽  
Dimensional Simulation ◽  
Shelf Region

<p>The slope area northeast of Taiwan was known as a hotspot for internal tides and internal solitary waves (ISWs), while their specific sources and generation mechanism of ISWs remain unclear. We investigate the generation and evolution processes of internal tides and ISWs with realistic configuration based on the high resolution non-hydrostatic numerical simulations. The ISWs northeastern Taiwan show a complex pattern according to the satellite image and our numerical results. ISWs propagate to various direction, and both shoreward and seaward propagating ISWs are generated on the continental slope. The ISWs observed on the continental slope-shelf region northeastern Taiwan can be generated by two ways. One is the local tide-topography interaction, and the other is the disintegration of remote internal tides generated over the I-Lan Ridge. The generated internal tides propagate northward to the Okinawa Trough, and can reach the continental slope-shelf region. During the propagation of the internal tides, the internal tides start to steepen and internal solitary waves are formed about 80 km north of I-Lan Ridge. The amplitude of the generated internal solitary waves is about 30 m. Furthermore, the Kuroshio is important to modulate the propagation and evolution of internal tides and ISWs, especially to the complexity of the ISW spatial pattern. We revealed most of the generated internal wave energy is dissipated locally over the double-canyon region, and strong mixing occur over the canyons.</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.

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