Parabolic equation modeling of high frequency acoustic transmission with an evolving sea surface

2012 ◽  
Vol 132 (3) ◽  
pp. 1311-1318 ◽  
Author(s):  
J. Senne ◽  
A. Song ◽  
M. Badiey ◽  
K. B. Smith
Keyword(s):  
Parabolic Equation ◽  
High Frequency ◽  
Sea Surface ◽  
Equation Modeling ◽  
Acoustic Transmission

Efficient, high‐frequency, parabolic‐equation modeling with surface scattering loss

1988 ◽  
Vol 83 (S1) ◽  
pp. S10-S10
Author(s):  
Martha E. M. Head ◽  
Eleanor S. Holmes ◽  
Lewis B. Dozier ◽  
W. Jobst
Keyword(s):  
Parabolic Equation ◽  
High Frequency ◽  
Surface Scattering ◽  
Equation Modeling ◽  
Scattering Loss

scholarly journals Parabolic Equation Modeling of Electromagnetic Wave Propagation over Rough Sea Surfaces

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1252 ◽  
Author(s):  
Ying Gao ◽  
Qun Shao ◽  
Binzhou Yan ◽  
Qifan Li ◽  
Shuxia Guo
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Parabolic Equation ◽  
Electromagnetic Wave Propagation ◽  
Sea Surface ◽  
Equation Modeling ◽  
Surface Model ◽  
Atmospheric Dust ◽  
Maritime Environment ◽  
Rough Sea

The parabolic equation is an efficient numerical solution for electromagnetic wave propagation. In order to address the difficulties in predicting electromagnetic wave propagation in the maritime environment caused by atmospheric dust and rough sea surfaces, and the shortcomings of the existing research that cannot fully reflect the rough characteristics of sea surfaces, the authors have modelled electromagnetic wave propagation in the maritime environment, including in the presence of atmospheric dust. In this study the authors present a parabolic equation modeling method for calculating the electromagnetic wave propagation over rough sea surfaces. Firstly, the rough sea surface is generated by building a double summation model of three-dimensional random sea surface. Then, combined with the piecewise linear shift transformation method of the parabolic equation model, the parabolic equation random sea surface model is constructed, and the electromagnetic wave propagation characteristics in a rough sea environment are analyzed. Finally, a large number of results are compared with the Miler-Brown model and shadow effect model in rough sea environments, which verifies that the random sea surface model can better characterize the influence of rough sea surfaces on electromagnetic wave propagation. The model can be used to improve the reliability of marine microwave communication links and the detection performance of ship-borne radar.

ИССЛЕДОВАНИЯ АКУСТИЧЕСКИХ ХАРАКТЕРИСТИК ВЕРХНЕГО СЛОЯ МОРЯ МЕТОДОМ МНОГОЧАСТОТНОГО АКУСТИЧЕСКОГО ЗОНДИРОВАНИЯ

2020 ◽  
Author(s):  
V.A. Bulanov ◽  
I.V. Korskov ◽  
A.V. Storozhenko ◽  
S.N. Sosedko
Keyword(s):  
High Frequency ◽  
Wave Motion ◽  
High Spatial Resolution ◽  
Wind Waves ◽  
Acoustic Parameter ◽  
Sea Surface ◽  
Near Surface ◽  
Acoustical Properties ◽  
Acoustic Spectroscopy ◽  
Sea Bottom

Описано применение акустического зондирования для исследования акустических характеристик верхнего слоя моря с использованием широкополосных остронаправленных инвертированных излучателей,устанавливаемых на дно. В основу метода положен принцип регистрации обратного рассеяния и отраженияот поверхности моря акустических импульсов с различной частотой, позволяющий одновременно измерятьрассеяние и поглощение звука и нелинейный акустический параметр морской воды. Многочастотное зондирование позволяет реализовать акустическую спектроскопию пузырьков в приповерхностных слоях моря,проводить оценку газосодержания и получать данные о спектре поверхностного волнения при различных состояниях моря вплоть до штормовых. Применение остронаправленных высокочастотных пучков ультразвукапозволяет разделить информацию о планктоне и пузырьках и определить с высоким пространственным разрешением структуру пузырьковых облаков, образующихся при обрушении ветровых волн, и структуру планктонных сообществ. Участие планктона в волновом движении в толще морской воды позволяет определитьпараметры внутренних волн спектр и распределение по амплитудам в различное время.This paper represents the application of acoustic probingfor the investigation of acoustical properties of the upperlayer of the sea using broadband narrow-beam invertedtransducers that are mounted on the sea bottom. Thismethod is based on the principle of the recording of thebackscattering and reflections of acoustic pulses of differentfrequencies from the sea surface. That simultaneouslyallows measuring scattering and absorption of the soundand non-linear acoustic parameter of seawater. Multifrequencyprobing allows performing acoustic spectroscopy ofbubbles in the near-surface layer of the sea, estimating gascontent, and obtaining data on the spectrum of the surfacewaves in various states of the sea up to a storm. Utilizationof the high-frequency narrow ultrasound beams allows us toseparate the information about plankton and bubbles and todetermine the structure of bubble clouds, created during thebreaking of wind waves, along with the structure of planktoncommunities with high spatial resolution. The participationof plankton in the wave motion in the seawater columnallows determining parameters of internal waves, such asspectrum and distribution of amplitudes at different times.

scholarly journals Rapid observations of ocean dynamics and stratification along a steep island coast during Hurricane María

2021 ◽  
Vol 7 (20) ◽  
pp. eabf1552
Author(s):  
Olivia M. Cheriton ◽  
Curt D. Storlazzi ◽  
Kurt J. Rosenberger ◽  
Clark E. Sherman ◽  
Wilford E. Schmidt
Keyword(s):  
Puerto Rico ◽  
Water Column ◽  
High Frequency ◽  
Coastal Communities ◽  
Ocean Dynamics ◽  
Sea Surface ◽  
Hurricane Intensity ◽  
Island Coast ◽  
New Framework ◽  
Insular Shelf

Hurricanes are extreme storms that affect coastal communities, but the linkages between hurricane forcing and ocean dynamics remain poorly understood. Here, we present full water column observations at unprecedented resolution from the southwest Puerto Rico insular shelf and slope during Hurricane María, representing a rare set of high-frequency, subsurface, oceanographic observations collected along an island margin during a hurricane. The shelf geometry and orientation relative to the storm acted to stabilize and strengthen stratification. This maintained elevated sea-surface temperatures (SSTs) throughout the storm and led to an estimated 65% greater potential hurricane intensity contribution at this site before eye passage. Coastal cooling did not occur until 11 hours after the eye passage. Our findings present a new framework for how hurricane interaction with insular island margins may generate baroclinic processes that maintain elevated SSTs, thus potentially providing increased energy for the storm.

On the solutions of a fourth order parabolic equation modeling epitaxial thin film growth

2016 ◽  
Vol 66 (3) ◽  
Author(s):  
Ning Duan ◽  
Xiaopeng Zhao ◽  
Xiufang Zhao
Keyword(s):  
Thin Film ◽  
Parabolic Equation ◽  
Fourth Order ◽  
Film Growth ◽  
Thin Film Growth ◽  
Equation Modeling ◽  
Epitaxial Thin Film ◽  
Epitaxial Thin Film Growth ◽  
Order Parabolic Equation ◽  
Fourth Order Parabolic Equation

AbstractIn this paper, we study the existence and uniqueness of global weak solution, the regularity of the solutions and the existence of global attractor for a fourth order parabolic equation modeling epitaxial thin film growth with Neumann boundary conditions in two space dimensions.

scholarly journals Ice-edge detection from Japanese C-band radar and high-frequency radar coastal stations

2013 ◽  
Vol 54 (62) ◽  
pp. 59-64 ◽  
Author(s):  
K. Shirasawa ◽  
N. Ebuchi ◽  
M. Leppäranta ◽  
T. Takatsuka
Keyword(s):  
Sea Ice ◽  
Edge Detection ◽  
High Frequency ◽  
Open Water ◽  
Radar Data ◽  
Hf Radar ◽  
Sea Surface ◽  
Geometrical Structures ◽  
Overlapping Data ◽  
Ice Edge

AbstractA C-band sea-ice radar (SIR) network system was operated to monitor the sea-ice conditions off the Okhotsk Sea coast of northern Hokkaido, Japan, from 1969 to 2004. The system was based on three radar stations, which were capable of continuously monitoring the sea surface as far as 60 km offshore along a 250 km long coastal section. In 2004 the SIR system was closed down and a sea surface monitoring programme was commenced using high-frequency (HF) radar; this system provides information on surface currents in open-water conditions, while areas with ‘no signal’ can be identified as sea ice. The present study compares HF radar data with SIR data to evaluate their feasibility for sea-ice remote sensing. The period of overlapping data was 1.5 months. The results show that HF radar information can be utilized for ice-edge mapping although it cannot fully compensate for the loss of the SIR system. In particular, HF radar does not provide ice concentration, ice roughness and geometrical structures or ice kinematics. The probability of ice-edge detection by HF radar was 0.9 and the correlation of the ice-edge distance between the radars was 0.7.

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