A Nearshore Oceanic Front Induced By Wave Streaming

Journal of Physical Oceanography ◽

10.1175/jpo-d-21-0004.1 ◽

2021 ◽

Author(s):

Peng Wang ◽

James C. McWilliams ◽

Yusuke Uchiyama

Keyword(s):

Numerical Simulation ◽

Surface Wave ◽

Cold Water ◽

Wave Direction ◽

Offshore Water ◽

Inner Shelf ◽

Overturning Circulation ◽

Oceanic Front ◽

Continental Shelves ◽

Offshore Transport

AbstractCoastal fronts impact cross-shelf exchange of materials, such as plankton and nutrients, which are important to the ecosystems in continental shelves. Here using numerical simulation we demonstrate a nearshore front induced by wave streaming. Wave streaming is a bottom Eulerian current along the surface wave direction, and it is caused by the wave bottom dissipation. Wave streaming drives a Lagrangian overturning circulation in the inner shelf and pumps up deep and cold water into the overturning circulation. The water inside the overturning circulation is quickly mixed and cooled because of the wave streaming-enhanced viscosity. However, the offshore water outside the overturning circulation remains stratified and warmer. Hence, a front develops between the water inside and outside the overturning circulation. The front is unstable and generates submesoscale shelf eddies, which lead the offshore transport across the front. This study presents a new mechanism for coastal frontogenesis.

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Mapping of Cold-Water Coral Carbonate Mounds Based on Geomorphometric Features: An Object-Based Approach

10.20944/preprints201712.0100.v1 ◽

2017 ◽

Author(s):

Markus Diesing ◽

Terje Thorsnes

Keyword(s):

Spatial Planning ◽

Cold Water ◽

Spatial Prediction ◽

Marine Spatial Planning ◽

Carbonate Mounds ◽

Multibeam Echosounder ◽

Continental Shelves ◽

Object Based ◽

Predicted Probability ◽

Water Coral

Cold-water coral reefs are rich, yet fragile ecosystems found in colder oceanic waters. Knowledge of their spatial distribution on continental shelves, slopes, seamounts and ridge systems is vital for marine spatial planning and conservation. Cold-water corals frequently form conspicuous carbonate mounds of varying sizes, which are identifiable from multibeam echosounder bathymetry and derived geomorphometric attributes. However, the often large number of mounds makes manual interpretation and mapping a tedious process. We present a methodology that combines image segmentation and random forest spatial prediction with the aim to derive maps of carbonate mounds and an associated measure of confidence. We demonstrate our method based on multibeam echosounder data from Iverryggen on the mid-Norwegian shelf. We identified the image-object mean planar curvature as the most important predictor. The presence and absence of carbonate mounds is mapped with high accuracy (overall accuracy = 84.4%, sensitivity = 0.827 and specificity = 0.866). Spatially-explicit confidence in the predictions is derived from the predicted probability and whether the predictions are within or outside the modelled range of values and is generally high. We plan to apply the showcased method to other areas of the Norwegian continental shelf and slope where MBES data have been collected with the aim to provide crucial information for marine spatial planning.

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Numerical simulation on cold water discharge of Nanshan LNG project in Longkou

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/612/1/012055 ◽

2020 ◽

Vol 612 ◽

pp. 012055

Author(s):

S S Yao ◽

Z Zhang

Keyword(s):

Numerical Simulation ◽

Cold Water ◽

Water Discharge

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Numerical Simulation for Two-Dimensional Surface Wave Structure of a Vertical Liquid Falling Film

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.72.1652 ◽

2006 ◽

Vol 72 (719) ◽

pp. 1652-1658

Author(s):

Chiaki KINO ◽

Tomoaki KUNUGI ◽

Akimi SERIZAWA

Keyword(s):

Numerical Simulation ◽

Surface Wave ◽

Wave Structure ◽

Falling Film ◽

Two Dimensional ◽

Dimensional Surface

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Brief communication: Modulation instability of internal waves in a smoothly stratified shallow fluid with a constant buoyancy frequency

Natural Hazards and Earth System Science ◽

10.5194/nhess-19-583-2019 ◽

2019 ◽

Vol 19 (3) ◽

pp. 583-587 ◽

Cited By ~ 2

Author(s):

Kwok Wing Chow ◽

Hiu Ning Chan ◽

Roger H. J. Grimshaw

Keyword(s):

Numerical Simulation ◽

Surface Wave ◽

Internal Waves ◽

Modulation Instability ◽

Rogue Waves ◽

Buoyancy Frequency ◽

Spontaneous Generation ◽

Large Displacements ◽

Analytical Treatment ◽

Intermediate Depth

Abstract. Unexpectedly large displacements in the interior of the oceans are studied through the dynamics of packets of internal waves, where the evolution of these displacements is governed by the nonlinear Schrödinger equation. In cases with a constant buoyancy frequency, analytical treatment can be performed. While modulation instability in surface wave packets only arises for sufficiently deep water, “rogue” internal waves may occur in shallow water and intermediate depth regimes. A dependence on the stratification parameter and the choice of internal modes can be demonstrated explicitly. The spontaneous generation of rogue waves is tested here via numerical simulation.

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Numerical simulation of pounding damage to caisson under storm surge

E3S Web of Conferences ◽

10.1051/e3sconf/20183803046 ◽

2018 ◽

Vol 38 ◽

pp. 03046

Author(s):

Chen Yu

Keyword(s):

Numerical Simulation ◽

Storm Surge ◽

Failure Mode ◽

Structural Model ◽

Time History ◽

Element Model ◽

Wave Force ◽

New Method ◽

Wave Direction ◽

Force Time

In this paper, a new method for the numerical simulation of structural model is proposed，which is employed to analyze the pounding response of caissons subjected to storm surge loads．According to the new method，the simulation process is divided into two steps. Firstly, the wave propagation caused by storm surge is simulated by the wave-generating tool of Flow-3D, and recording the wave force time history on the caisson. Secondly，a refined 3D finite element model of caisson is established，and the wave force load is applied on the caisson according to the measured data in the first step for further analysis of structural pounding response using the explicit solver of LSDYNA. The whole simulation of pounding response of a caisson caused by “Sha Lijia” typhoon is carried out. The results show that the different wave direction results in the different angle caisson collisions, which will lead to different failure mode of caisson, and when the angle of 60 between wave direction and front/back wall is simulated, the numerical pounding failure mode is consistent with the situation.

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Numerical simulation of the December 4, 2007 landslide-generated tsunami in Chehalis Lake, Canada

Geophysical Journal International ◽

10.1093/gji/ggv026 ◽

2015 ◽

Vol 201 (1) ◽

pp. 372-376 ◽

Cited By ~ 25

Author(s):

Jiajia Wang ◽

Steven N. Ward ◽

Lili Xiao

Keyword(s):

Numerical Simulation ◽

Wave Energy ◽

Progressive Failure ◽

Wave Direction ◽

Field Surveys ◽

Slide Mass ◽

Initial Wave ◽

Flow Speeds ◽

Tsunami Squares ◽

Wave Size

Abstract On December 4, 2007, a three million cubic metres landslide impacted Chehalis Lake, 80 km east of Vancouver, Canada. The failed mass rushed into the lake and parented a tsunami that ran up 38 m on the opposite shore, destroyed trees, roads and campsite facilities. Armed with field surveys and multihigh-tech observations from SONAR, LiDAR and orthophotographs, we apply the newly developed ‘Tsunami Squares’ method to simulate the Chehalis Lake landslide and its generated tsunami. The landslide simulation shows a progressive failure, flow speeds up to ∼60 m s–1, and a slide mass stoppage with uniform repose angle on the lakebed. Tsunami products suggest that landslide velocity and spatial scale influence the initial wave size, while wave energy decay and inundation heights are affected by a combination of distance to the landslide, bathymetry and shoreline orientation relative to the wave direction.

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