scholarly journals Dynamics and Transformation of Sea Surface Gravity Waves at the Shelf of Decreasing Depth

2021 ◽  
Vol 9 (8) ◽  
pp. 861
Author(s):  
Grigory I. Dolgikh ◽  
Olga S. Gromasheva ◽  
Stanislav G. Dolgikh ◽  
Alexander A. Plotnikov
Keyword(s):  
Sea Of Japan ◽  
Gravity Waves ◽  
Surf Zone ◽  
Sea Surface ◽  
The Sea Of Japan ◽  
Surface Gravity Waves ◽  
Half Wavelength ◽  
Progressive Waves ◽  
Crust Deformation ◽  
Laser Strainmeters

This paper reviews the results of the processing of synchronized data on hydrosphere pressure variations and the Earth’s crust deformation in the microseismic range (5–15 s), obtained over the course of numerous experiments, using a coastal laser strainmeter and laser meters of hydrosphere pressure variations installed in various points of the Sea of Japan shelf. Interpreting the results, we have discovered new regularities in the dynamics of surface progressive gravity waves, and their transformation into primary microseisms, when waves move at the shelf of decreasing depth. For example, we found non-isochronous behavior of progressive waves, which manifests itself in a decrease in the periods of gravity waves due to the transformation of a part of their energy into the energy of primary microseisms. Furthermore, when processing the synchronous fragments of the records, made by laser strainmeters and laser meters of hydrosphere pressure variations, we identified approximate zones of the most effective transformation of the energy of gravity progressive waves into the energy of primary microseisms, which start from the depth of less than a half-wavelength and stretch to the surf zone.

Measuring Sea Surface Gravity Waves Using Smartphones

Ports 2019 ◽  
2019 ◽  
Author(s):  
Matheus de Paula Vieira ◽  
Pedro Veras Guimarães
Keyword(s):  
Gravity Waves ◽  
Sea Surface ◽  
Surface Gravity ◽  
Surface Gravity Waves

Sea Surface Gravity Waves Excited by Dynamic Ground Motions from Large Regional Earthquakes

2020 ◽  
Vol 91 (4) ◽  
pp. 2268-2277 ◽  
Author(s):  
Yoshihiro Ito ◽  
Spahr C. Webb ◽  
Yoshihiro Kaneko ◽  
Laura M. Wallace ◽  
Ryota Hino
Keyword(s):  
Gravity Waves ◽  
Seismic Waves ◽  
Ground Motions ◽  
Maximum Amplitude ◽  
Sea Surface ◽  
Surface Gravity ◽  
Accretionary Wedge ◽  
Low Velocity ◽  
Infragravity Waves ◽  
Surface Gravity Waves

Abstract Infragravity waves on the sea surface near coastlines are occasionally excited by static displacement caused by large local earthquakes and recorded as tsunamis. However, tsunamis induced by ground motions from seismic waves are rarely observed, especially far from earthquake focal areas. We investigated seafloor pressure variations in the infragravity band at the Hikurangi subduction zone following the M 7.8 Kaikōura and M 7.1 Te Araroa earthquakes. Anomalous infragravity waves were observed at 0.2–20 mHz at sites overlying a low-velocity accretionary wedge offshore of the east coast of New Zealand’s North Island accompanying the Rayleigh-wave arrivals. The maximum amplitude of these ultra-low-frequency waves was similar to the tsunami that propagated from the earthquake focal area hours later. The amplitude of the pressure signal from these waves observed offshore varied inversely with water depth, suggesting that sea surface gravity waves were excited by Rayleigh or Love waves amplified within the accretionary wedge.

Phase velocity and dispersion relations of surface gravity waves in shallow sea

1994 ◽  
Vol 45 (6) ◽  
pp. 993
Author(s):  
VA Kalmykov
Keyword(s):  
Phase Velocity ◽  
Gravity Waves ◽  
Experimental Studies ◽  
Finite Depth ◽  
Dispersion Relations ◽  
Sea Surface ◽  
Surface Gravity ◽  
Linear Wave ◽  
Shallow Sea ◽  
Surface Gravity Waves

Phase velocity and dispersion relations of surface gravity waves on the sea have been modelled by two numerical methods and the results compared with previous experimental studies. Wave nonlinearities cause deviations from linear wave relations and these deviations are seen on the sea surface in the form of sharply crested waves. The effects are amplified if wave steepness increases or wave spectra become narrower. When the effects of finite depth of water are included in the calculations, the deviations from linearity are found to increase significantly.

scholarly journals Observations and a Model of Undertow over the Inner Continental Shelf

2008 ◽  
Vol 38 (11) ◽  
pp. 2341-2357 ◽  
Author(s):  
Steven J. Lentz ◽  
Melanie Fewings ◽  
Peter Howd ◽  
Janet Fredericks ◽  
Kent Hathaway
Keyword(s):  
Gravity Waves ◽  
Vertical Structure ◽  
Surf Zone ◽  
Stokes Drift ◽  
Vertical Shear ◽  
Surface Gravity ◽  
Linear Wave ◽  
Surface Gravity Waves ◽  
Offshore Flow ◽  
Offshore Transport

Abstract Onshore volume transport (Stokes drift) due to surface gravity waves propagating toward the beach can result in a compensating Eulerian offshore flow in the surf zone referred to as undertow. Observed offshore flows indicate that wave-driven undertow extends well offshore of the surf zone, over the inner shelves of Martha’s Vineyard, Massachusetts, and North Carolina. Theoretical estimates of the wave-driven offshore transport from linear wave theory and observed wave characteristics account for 50% or more of the observed offshore transport variance in water depths between 5 and 12 m, and reproduce the observed dependence on wave height and water depth. During weak winds, wave-driven cross-shelf velocity profiles over the inner shelf have maximum offshore flow (1–6 cm s−1) and vertical shear near the surface and weak flow and shear in the lower half of the water column. The observed offshore flow profiles do not resemble the parabolic profiles with maximum flow at middepth observed within the surf zone. Instead, the vertical structure is similar to the Stokes drift velocity profile but with the opposite direction. This vertical structure is consistent with a dynamical balance between the Coriolis force associated with the offshore flow and an along-shelf “Hasselmann wave stress” due to the influence of the earth’s rotation on surface gravity waves. The close agreement between the observed and modeled profiles provides compelling evidence for the importance of the Hasselmann wave stress in forcing oceanic flows. Summer profiles are more vertically sheared than either winter profiles or model profiles, for reasons that remain unclear.

scholarly journals Freely Decaying Weak Turbulence for Sea Surface Gravity Waves

2002 ◽  
Vol 89 (14) ◽  
Author(s):  
M. Onorato ◽  
A. R. Osborne ◽  
M. Serio ◽  
D. Resio ◽  
A. Pushkarev ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Sea Surface ◽  
Surface Gravity ◽  
Weak Turbulence ◽  
Surface Gravity Waves

Effects of Wave Streaming and Wave Variations on Nearshore Wave-Driven Circulation

2020 ◽  
Vol 50 (10) ◽  
pp. 3025-3041
Author(s):  
Peng Wang ◽  
James C. McWilliams ◽  
Yusuke Uchiyama ◽  
Mickaël D. Chekroun ◽  
Daling Li Yi
Keyword(s):  
Numerical Simulations ◽  
Gravity Waves ◽  
Wave Breaking ◽  
Surf Zone ◽  
Material Transport ◽  
Inner Shelf ◽  
Surface Gravity Waves ◽  
Wave Heights ◽  
Passive Tracers ◽  
Mean Current

AbstractWave streaming is a near-bottom mean current induced by the bottom drag on surface gravity waves. Wave variations include the variations in wave heights, periods, and directions. Here we use numerical simulations to study the effects of wave streaming and wave variations on the circulation that is driven by incident surface waves. Wave streaming induces an inner-shelf Lagrangian overturning circulation, which links the inner shelf with the surf zone. Wave variations cause alongshore-variable wave breaking that produces surf eddies; however, such eddies can be suppressed by wave streaming. Moreover, with passive tracers we show that wave streaming and wave variations together enhance the cross-shelf material transport.

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