Ambient noise generated by surface wind waves—Numerical and experimental results.

1996 ◽  
Vol 99 (4) ◽  
pp. 2454-2457
Author(s):  
Jin‐Yuan Liu ◽  
Chuen‐Song Chen
Keyword(s):  
Ambient Noise ◽  
Wind Waves ◽  
Surface Wind ◽  
Experimental Results

A Method for Noise Source Levels Inversion with Underwater Ambient Noise Generated by Typhoon in Deep Ocean

2018 ◽  
Vol 26 (02) ◽  
pp. 1850007 ◽  
Author(s):  
Qiulong Yang ◽  
Kunde Yang ◽  
Shunli Duan
Keyword(s):  
Ambient Noise ◽  
Noise Source ◽  
Surface Wind ◽  
Deep Ocean ◽  
Noise Sources ◽  
Noise Field ◽  
Sea Surface Wind ◽  
Source Level ◽  
The Western Pacific ◽  
Good Agreement

Sea-surface wind agitation can be considered the dominant noise sources whose intensity relies on local wind speed during typhoon period. Noise source levels in previous researches may be unappreciated for all oceanic regions and should be corrected for modeling typhoon-generated ambient noise fields in deep ocean. This work describes the inversion of wind-driven noise source level based on a noise field model and experimental measurements, and the verification of the inverted noise source levels with experimental results during typhoon period. A method based on ray approach is presented for modeling underwater ambient noise fields generated by typhoons in deep ocean. Besides, acoustic field reciprocity is utilized to decrease the calculation amount in modeling ambient noise field. What is more, the depth dependence and the vertical directionality of noise field based on the modeling method and the Holland typhoon model are evaluated and analyzed in deep ocean. Furthermore, typhoons named “Soulik” in 2013 and “Nida” in 2016 passed by the receivers deployed in the western Pacific (WP) and the South China Sea (SCS). Variations in sound speed profile, bathymetry, and the related oceanic meteorological parameters are analyzed and taken into consideration for modeling noise field. Boundary constraint simulated annealing (SA) method is utilized to invert the three parameters of noise source levels and to minimize the objective function value. The prediction results with the inverted noise source levels exhibit good agreement with the measured experiment data and are compared with predicted results with other noise sources levels derived in previous researches.

scholarly journals Impacts on wave-driven harbour agitation due to climate change in Catalan ports

2015 ◽  
Vol 15 (8) ◽  
pp. 1695-1709 ◽  
Author(s):  
J. P. Sierra ◽  
M. Casas-Prat ◽  
M. Virgili ◽  
C. Mösso ◽  
A. Sánchez-Arcilla
Keyword(s):  
Climate Change ◽  
Wind Waves ◽  
Surface Wind ◽  
Qualitative Assessment ◽  
Type Model ◽  
Slight Reduction ◽  
Wind Fields ◽  
General Applicability ◽  
Nw Mediterranean ◽  
Offshore Wave

Abstract. The objective of the present work is to analyse how changes in wave patterns due to the effect of climate change can affect harbour agitation (oscillations within the port due to wind waves). The study focuses on 13 harbours located on the Catalan coast (NW Mediterranean) using a methodology with general applicability. To obtain the patterns of agitation, a Boussinesq-type model is used, which is forced at the boundaries by present/future offshore wave conditions extracted from recently developed high-resolution wave projections in the NW Mediterranean. These wave projections were obtained with the SWAN model forced by present/future surface wind fields projected, respectively, by five different combinations of global and regional circulation models (GCMs and RCMs) for the A1B scenario. The results show a general slight reduction in the annual average agitation for most of the ports, except for the northernmost and southernmost areas of the region, where a slight increase is obtained. A seasonal analysis reveals that the tendency to decrease is accentuated in winter. However, the inter-model variability is large for both the winter and the annual analysis. Conversely, a general increase with a larger agreement among models is found during summer, which is the period with greater activity in most of the studied ports (marinas). A qualitative assessment of the factors of variability seems to indicate that the choice of GCM tends to affect the spatial pattern, whereas the choice of RCM induces a more homogeneous bias over the regional domain.

scholarly journals Green–Naghdi dynamics of surface wind waves in finite depth

2018 ◽  
Vol 50 (2) ◽  
pp. 025514
Author(s):  
M A Manna ◽  
A Latifi ◽  
R A Kraenkel
Keyword(s):  
Wind Waves ◽  
Surface Wind ◽  
Finite Depth

A Model of Strongly Forced Wind Waves

2009 ◽  
Vol 39 (10) ◽  
pp. 2502-2522 ◽  
Author(s):  
Alexey V. Fedorov ◽  
W. Kendall Melville
Keyword(s):  
Wind Stress ◽  
Wave Breaking ◽  
Wind Waves ◽  
Surface Wind ◽  
Finite Width ◽  
Hydraulic Jumps ◽  
Turbulent Layer ◽  
Near Surface ◽  
Layer Interface ◽  
Forced Waves

Abstract A model of surface waves generated on deep water by strong winds is proposed. A two-layer approximation is adopted, in which a shallow turbulent layer overlies the lower, infinitely deep layer. The dynamics of the upper layer, which is directly exposed to the wind, are nonlinear and coupled to the linear dynamics in the deep fluid. The authors demonstrate that in such a system there exist steady wave solutions characterized by confined regions of wave breaking alternating with relatively long intervals where the wave profiles change monotonically. In the former regions the flow is decelerated; in the latter it is accelerated. The regions of breaking are akin to hydraulic jumps of finite width necessary to join the smooth “interior” flows and have periodic waves. In contrast to classical hydraulic jumps, the strongly forced waves lose both energy and momentum across the jumps. The flow in the upper layer is driven by the balance between the wind stress at the surface, the turbulent drag applied at the layer interface, and the wave drag induced at the layer interface by quasi-steady breaking waves. Propagating in the downwind direction, the strongly forced waves significantly modify the flow in both layers, lead to enhanced turbulence, and reduce the speed of the near-surface flow. According to this model, a large fraction of the work done by the surface wind stress on the ocean in high winds may go directly into wave breaking and surface turbulence.

Assessment of energy resources of Polish Baltic Sea areas

2017 ◽  
Vol 32 (1) ◽  
pp. 93-102
Author(s):  
Maciej Kałas ◽  
Piotr Piotrowski
Keyword(s):  
Power Plants ◽  
Numerical Models ◽  
Wind Waves ◽  
Surface Wind ◽  
Sea Surface ◽  
Energy Resources ◽  
Near Surface ◽  
Sea Surface Wind ◽  
Physical Energy ◽  
Physical Phenomena

The article presents spatial characteristics of energy fluxes recorded in the area of the Polish Exclusive Economic Zone (EEZ) in the four-year period of 2013–16. Data presented in this work are based on results of forecast calculations with the application of numerical models of the atmosphere (HIRLAM) and sea (WAM and HIROMB). Conducted analyses were concerned with dynamics of physical phenomena above the sea surface (wind), on its surface (wind waves motion), and in its near-surface layer up to 4 m (seawater flows). Physical energy resources connected with these processes for subsequent four years were computed and compared with the amount of annual electricity output generated by conventional and renewable sources of energy. Such an analysis of estimated energy resources reveals that the resource is highly differentiated in terms of space and in individual years, and significantly exceed the annual production of Polish power plants.

Empirical Parameterization of the Wind-induced Drift Currents

2020 ◽  
Author(s):  
Vladislav Polnikov ◽  
Hongyu Ma
Keyword(s):  
Wind Waves ◽  
Wave Spectrum ◽  
Surface Wind ◽  
Wide Band ◽  
Stokes Drift ◽  
Wave Steepness ◽  
Mechanical Waves ◽  
Large Tank ◽  
First Time ◽  
Surface Drift

<p>Results of measurements of the drift currents induced by waves and wind at the wavy water surface are presented. The measurements were executed by means of surface floats in a large tank with the dimensions of 32.5x1x2 m<sup>3</sup>. Three cases were studied: (i) regular (narrow-band) mechanical waves; (ii) irregular (wide-band) mechanical waves; and (iii) wind waves.</p><p>The measured surface-drift currents induced by mechanical waves, U<sub>d</sub>, are compared with the Stokes drift at the surface, U<sub>St</sub>, estimated by the well-known formula with the integral over a wave spectrum. In this case, it was found that ratio U<sub>d</sub> / U<sub>St</sub> is varying in the range 0.5 – 0.93 and slightly growing with the decrease of wave steepness, having no visible dependence on the breaking intensity. These estimations are used to separate the wind-induced drift current, U<sub>dw</sub>, from the total drift at the presence of wind.</p><p>In the case of wind waves, the wind-induced part of the surface drift, U<sub>dw</sub>, is compared with the friction velocity, u<sub>*</sub>. In our measurements, the ratio U<sub>dw</sub> / u<sub>*</sub> varies systematically in the range 0.65 – 1.2. Taking into account the percentage of wave breaking, Br, the wave age, A, and the wave steepness, Ϭ = ak<sub>p</sub>, it was found the parameterization:  U<sub>dw</sub> = (Br + Ϭ A) u<sub>*</sub>, which corresponds to the observations with the mean error less than 10%. For the first time, this ratio provides the dependence of the surface wind drift on the surface wave parameters.</p>

Bifurcations and exact solutions for a nonlinear surface wind waves equation

2015 ◽  
Vol 39 (6) ◽  
pp. 1289-1297 ◽  
Author(s):  
Yongan Xie ◽  
Shengqiang Tang ◽  
Liyan Zhong ◽  
Ai-yong Chen
Keyword(s):  
Exact Solutions ◽  
Wind Waves ◽  
Surface Wind ◽  
Nonlinear Surface

scholarly journals Surface Roughness Imaging of Currents Shows Divergence and Strain in the Wind Direction

2014 ◽  
Vol 44 (8) ◽  
pp. 2153-2163 ◽  
Author(s):  
Nicolas Rascle ◽  
Bertrand Chapron ◽  
Aurélien Ponte ◽  
Fabrice Ardhuin ◽  
Patrice Klein
Keyword(s):  
Surface Roughness ◽  
Wind Direction ◽  
Wind Waves ◽  
Surface Wind ◽  
Surface Currents ◽  
Simple Method ◽  
Sea Surface Roughness ◽  
Deformation Properties ◽  
The Mean ◽  
Synthetic Aperture Radars

Abstract Images of sea surface roughness—for example, obtained by synthetic aperture radars (SAR) or by radiometers viewing areas in and around the sun glitter—at times provide clear observations of meso- and submesoscale oceanic features. Interacting with the surface wind waves, particular deformation properties of surface currents are responsible for those manifestations. Ignoring other sources of surface roughness variations, the authors limit their discussion to the mean square slope (mss) variability. This study confirms that vortical currents and currents with shear in the wind direction shall not be expressed in surface roughness images. Only divergent currents or currents with no divergence but strained in the wind direction can exhibit surface roughness signatures. More specifically, nondivergent currents might be traced with a 45° sensitivity to the wind direction. A simple method is proposed in order to interpret high-resolution roughness images, where roughness variations are proportional to ∂u/∂x + α∂υ/∂y, a linear combination of the along-wind and crosswind current gradients. The polarization parameter α depends upon the sensor look direction and the directional properties of the surface waves selected by the sensor. The use of multiple look directions or possible acquisitions with different wind directions shall thus help to retrieve surface currents from surface roughness observations.

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