Radiation of multi-source and multi-band internal waves in the northwestern Pacific

2020 ◽  
Author(s):  
Yang Wang ◽  
Baoshu Yin
Keyword(s):  
Internal Wave ◽  
Internal Waves ◽  
World Ocean ◽  
Kuroshio Current ◽  
Source Model ◽  
Source Distribution ◽  
Northwestern Pacific ◽  
Ideal Line ◽  
Topographic Variability ◽  
Multi Band

<p>The northwestern Pacific is the most energetic area of internal waves in the world ocean. Generation and evolution processes of multi-source and multi-band internal waves at tidal frequency are examined by driving high-resolution numerical model. The semidiurnal and diurnal internal waves exhibit distinct-different generation and radiation patterns. The multi-source distribution of internal waves favours the occurrence of complex interference patterns which contribute significantly to the inhomogeneous internal wave field. The improved ideal line-source model can well reproduce the interference processes of both semidiurnal and diurnal internal waves. Simulation results show that geostrophic circulations such as Kuroshio Current, North Equator Current, influence both semidiurnal and diurnal internal waves’ radiation path. And this modulation process is further demonstrated by theoretical model. Energetic dissipation occurs both near the sources and in the basin. A locally dissipated fraction q ≤ 0.4 is estimated at the generation sites with continuous bathymetry features, while q ≥ 0.6 is estimated at areas with discrete topographic variability. A lower locally dissipated fraction indicates a higher proportion of internal wave energy radiating into the basin, where enhanced dissipation coincides closely with the interference-modulated flux field.</p>

An analogy between electromagnetic and internal waves

2019 ◽  
Vol 485 (4) ◽  
pp. 428-433
Author(s):  
V. G. Baydulov ◽  
P. A. Lesovskiy
Keyword(s):  
Angular Momentum ◽  
Conservation Laws ◽  
Internal Wave ◽  
Special Relativity ◽  
Internal Waves ◽  
Maxwell Equations ◽  
Wave Equations ◽  
Lagrange Function ◽  
Lorentz Transformations ◽  
Symmetry Transformations

For the symmetry group of internal-wave equations, the mechanical content of invariants and symmetry transformations is determined. The performed comparison makes it possible to construct expressions for analogs of momentum, angular momentum, energy, Lorentz transformations, and other characteristics of special relativity and electro-dynamics. The expressions for the Lagrange function are defined, and the conservation laws are derived. An analogy is drawn both in the case of the absence of sources and currents in the Maxwell equations and in their presence.

Density Wave Measurements in a Rectangular Clarifier

1983 ◽  
Vol 18 (1) ◽  
pp. 129-150 ◽  
Author(s):  
Mark K. Watson ◽  
R.R. Hudgins ◽  
P.L. Silveston
Keyword(s):  
Power Spectrum ◽  
Internal Wave ◽  
Internal Waves ◽  
Wave Motion ◽  
Wave Amplitude ◽  
Suspended Solids ◽  
Small Volume ◽  
Density Wave ◽  
Measure Concentration ◽  
Wave Measurements

Abstract Internal wave motion was studied in a laboratory rectangular, primary clarifier. A photo-extinction device was used as a turbidimeter to measure concentration fluctuations in a small volume within the clarifier as a function of time. The signal from this device was fed to a HP21MX minicomputer and the power spectrum plotted from data records lasting approximately 30 min. Results show large changes of wave amplitude as frequency increases. Two distinct regions occur: one with high amplitudes at frequencies below 0.03 Hz, the second with very small amplitudes appears for frequencies greater than 0.1 Hz. The former is associated with internal waves, the latter with flow-generated turbulence. Depth, velocity in the clarifier and inlet suspended solids influence wave amplitudes and the spectra. A variation with position or orientation of the probe was not detected. Contradictory results were found for the influence of flow contraction baffles on internal wave amplitude.

scholarly journals Impacts of the Kuroshio Intrusion through the Luzon Strait on the Local Precipitation Anomaly

2021 ◽  
Vol 13 (6) ◽  
pp. 1113
Author(s):  
Wen-Pin Fang ◽  
Ding-Rong Wu ◽  
Zhe-Wen Zheng ◽  
Ganesh Gopalakrishnan ◽  
Chung-Ru Ho ◽  
...  
Keyword(s):  
Kuroshio Current ◽  
Precipitation Anomaly ◽  
Luzon Strait ◽  
Sea Surface ◽  
Research Quality ◽  
Northwestern Pacific ◽  
Kuroshio Intrusion ◽  
Vertical Advection ◽  
Budget Analysis ◽  
The Kuroshio

The Kuroshio Current has its origin in the northwestern Pacific, flowing northward to the east of Taiwan and the northern part of Luzon Island. As the Kuroshio Current flows northward, it quasi-periodically intrudes (hereafter referred to as Kuroshio intrusion (KI)) into the northern South China Sea (SCS) basin through the Luzon Strait. Despite the complex generation mechanisms of KI, the purpose of this study is to improve our understanding of the effects of KI through the Luzon Strait on the regional atmospheric and weather variations. Long-term multiple satellite observations, including absolute dynamic topography, absolute geostrophic currents, sea surface winds by ASCAT, multi-scale ultra-high resolution sea surface temperature (MURSST) level-four analysis, and research-quality three-hourly TRMM multi-satellite precipitation analysis (TMPA), was used to systematically examine the aforementioned scientific problem. Analysis indicates that the KI is interlinked with the consequential anomalous precipitation off southwestern Taiwan. This anomalous precipitation would lead to ~560 million tons of freshwater influx during each KI event. Subsequently, independent moisture budget analysis suggests that moisture, mainly from vertical advection, is the possible source of the precipitation anomaly. Additionally, a bulk formula analysis was applied to understand how KI can trigger the precipitation anomaly through vertical advection of moisture without causing an evident change in the low-level flows. These new research findings might reconcile the divisiveness on why winds are not showing a synchronous response during the KI and consequential anomalous precipitation events.

A multi-layer model for nonlinear internal wave propagation in shallow water

2012 ◽  
Vol 695 ◽  
pp. 341-365 ◽  
Author(s):  
Philip L.-F. Liu ◽  
Xiaoming Wang
Keyword(s):  
Wave Propagation ◽  
Internal Wave ◽  
Shallow Water ◽  
Internal Waves ◽  
Bottom Topography ◽  
Laboratory Data ◽  
Constant Density ◽  
Layer Model ◽  
Fluid System ◽  
Nonlinear Internal Wave

AbstractIn this paper, a multi-layer model is developed for the purpose of studying nonlinear internal wave propagation in shallow water. The methodology employed in constructing the multi-layer model is similar to that used in deriving Boussinesq-type equations for surface gravity waves. It can also be viewed as an extension of the two-layer model developed by Choi & Camassa. The multi-layer model approximates the continuous density stratification by an $N$-layer fluid system in which a constant density is assumed in each layer. This allows the model to investigate higher-mode internal waves. Furthermore, the model is capable of simulating large-amplitude internal waves up to the breaking point. However, the model is limited by the assumption that the total water depth is shallow in comparison with the wavelength of interest. Furthermore, the vertical vorticity must vanish, while the horizontal vorticity components are weak. Numerical examples for strongly nonlinear waves are compared with laboratory data and other numerical studies in a two-layer fluid system. Good agreement is observed. The generation and propagation of mode-1 and mode-2 internal waves and their interactions with bottom topography are also investigated.

A conservation law for internal gravity waves

1976 ◽  
Vol 78 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Michael Milder
Keyword(s):  
Internal Wave ◽  
Group Velocity ◽  
Internal Waves ◽  
Gravity Waves ◽  
Conservation Law ◽  
Short Wavelength ◽  
Internal Gravity Waves ◽  
Volume Integral ◽  
Weak Density ◽  
Progressive Waves

The scaled vorticity Ω/N and strain ∇ ζ associated with internal waves in a weak density gradient of arbitrary depth dependence together comprise a quantity that is conserved in the usual linearized approximation. This quantity I is the volume integral of the dimensionless density DI = ½[Ω2/N2 + (∇ ζ)2]. For progressive waves the ‘kinetic’ and ‘potential’ parts are equal, and in the short-wavelength limit the density DI and flux FI are related by the ordinary group velocity: FI = DIcg. The properties of DI suggest that it may be a useful measure of local internal-wave saturation.

scholarly journals Pliocene ostracods (Crustacea) from the Togakushi area, central Japan; palaeobiogeography of trans-Arctic taxa and Japan Sea endemic species

2008 ◽  
Vol 27 (2) ◽  
pp. 161-175 ◽  
Author(s):  
Hirokazu Ozawa ◽  
Hideaki Nagamori ◽  
Tomotaka Tanabe
Keyword(s):  
High Latitude ◽  
Endemic Species ◽  
Japan Sea ◽  
Kuroshio Current ◽  
The Arctic ◽  
Northwestern Pacific ◽  
Arctic Seas ◽  
Central Japan ◽  
The Japan Sea ◽  
Northern Atlantic

Abstract. Pliocene strata (4–3 Ma) in the Togakushi area, central Japan, yield significant ostracods, which allow investigation of the origins of high-latitude (Arctic–Atlantic) taxa and the Japan Sea endemic species, together with their post-Miocene history of extinction-speciation and migration. Three types of extinct species are found here: (1) cryophilic species in common with, or closely related to, species in Plio-Pleistocene assemblages described from the Japan Sea; (2) species closely related to, or comparable with, species that characterize Miocene Japan; and (3) species endemic to the Pliocene Japan Sea. Type (1) contains species closely related to high-latitude species known from the Arctic and northern Atlantic Oceans. Their presence suggests migration from the northwestern Pacific to the northern Atlantic through the Arctic seas since the Late Pliocene after the opening of the Bering Strait. Both Types (2) and (3) contain genera originating in the south, which show high specific diversity in regions affected by the modern warm Kuroshio Current. Ancestral ostracods of Types (2) and (3) invaded the Japan Sea from the Pacific from the Middle Miocene, and diversified to produce closely related species in the semi land-locked Japan Sea until the Early Pliocene. Two new species Aurila togakushiensis sp. nov. and Aurila shigaramiensis sp. nov. are described.

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