scholarly journals Polarimetric Scattering from Two-Dimensional Dielectric Rough Sea Surface with a Ship-Induced Kelvin Wake

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Pengju Yang ◽  
Lixin Guo
Keyword(s):  
Electromagnetic Scattering ◽  
Sea Surface ◽  
Two Dimensional ◽  
Ship Wake ◽  
Enhanced Backscattering ◽  
Rough Sea Surface ◽  
Configuration Simulation ◽  
Depolarized Scattering ◽  
Limited Surface ◽  
Rough Sea

Based on the polarimetric scattering model of second-order small-slope approximation (SSA-II) with tapered wave incidence for reducing the edge effect caused by limited surface size, monostatic and bistatic polarimetric scattering signatures of two-dimensional dielectric rough sea surface with a ship-induced Kelvin wake is investigated in detail by comparison with those of sea surface without ship wake. The emphasis of this paper is on an investigation of depolarized scattering and enhanced backscattering of sea surface with a ship wake that changes the sea surface geometric structure especially for low wind conditions. Numerical simulations show that in the plane of incidence rough sea surface scattering is dominated by copolarized scattering rather than cross-polarized scattering and that under low wind conditions a larger ship speed gives rise to stronger enhanced backscattering and enhanced depolarized scattering. For both monostatic and bistatic configuration, simulation results indicate that electromagnetic scattering signatures in the presence of a ship wake dramatically differ from those without ship wake, which may serve as a basis for the detection of ships in marine environment.

scholarly journals Angular Composite Facet Model with Shadowing Treatment for Backscattering from Two-Dimensional Rough Sea Surface

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 402
Author(s):  
Xiaojun Wang ◽  
Xingyuan You ◽  
Nan Bi ◽  
Tao Jiang
Keyword(s):  
Incident Angle ◽  
Sea Surface ◽  
Ocean Wave ◽  
Two Dimensional ◽  
Ship Wake ◽  
Shadowing Effects ◽  
Scattering Contribution ◽  
Rough Sea Surface ◽  
Facet Model ◽  
Rough Sea

Recent diverse applications on ocean wave synthetic aperture radar (SAR) images have a potential demand for individual facet scattering contribution rather than the total average radar cross-section (RCS) by statistical scattering models. However, only a few facet methods have been proposed and fewer have considered shadowing effects, which are thought to be non-negligible at large incident angle. In view of this, we proposed an angular composite facet model (ACFM) with shadowing treatment to investigate the backscattering from two-dimensional rough sea surface. First, a region division formula for ACFM without shadowing treatment is proposed to classified sea surface facets into specular facets and diffusion facets based on which kind of scattering is dominate from each facet, and the corresponding scattering contribution is calculated either by Kirchhoff approximation (KA) or by a small perturbation method (SPM) with a tilting process. Second, an electromagnetic shadowing algorithm based on facets grouping is adopted to handle the shadowing effects in a geometric manner with moderate computation complexity gained. Finally, comparisons between numerical backscattering evaluations and experimental data demonstrate that this new ACFM can attain accurate numerical results and the geometric facets grouping method is a practical way to tackle shadowing effects despite a certain acceptable gap. Therefore, the whole ACFM can simulate ocean wave SAR imaging, especially for those electrically large surfaces and to evaluate the scattering from sea surface with different local nature, such as sea spikes, foams, spilled oil, swells, and ship wake.

scholarly journals Study of electromagnetic scattering from two-dimensional rough sea surface based on improved Wen’s spectrum

2014 ◽  
Vol 63 (13) ◽  
pp. 134203
Author(s):  
Wu Geng-Kun ◽  
Ji Guang-Rong ◽  
Ji Ting-Ting ◽  
Ren Hong-Xia
Keyword(s):  
Electromagnetic Scattering ◽  
Sea Surface ◽  
Two Dimensional ◽  
Rough Sea Surface ◽  
Rough Sea

The Study on a New Approximate Method of Computing Electromagnetic Scattering from Multilayer Rough Sea Surfaces

2014 ◽  
Vol 533 ◽  
pp. 268-273
Author(s):  
Jia Sheng Tian ◽  
Wan Pan ◽  
Jian Shi
Keyword(s):  
Electromagnetic Scattering ◽  
Computation Time ◽  
Sea Surface ◽  
Analysis Method ◽  
Large Matrix ◽  
Random Rough Surfaces ◽  
Strong Winds ◽  
Rough Sea Surface ◽  
Rough Sea ◽  
Good Agreement

At high sea states strong winds make the sea surface broken, and become a multilayer-rough sea surface made of a large number of foams and droplets. Similarly, if the sea surface covered by oil and other dirts will also belong to the mutilayer rough sea surfaces of various medium properties. In this paper, applying the Kirchhoff Approximation (KA) and the electromagnetic theory of stratified media, electromagnetic scattering characteristics from a multilayer rough medium surface are calculated. Firstly, a detailed analysis of electromagnetic reflection from multilayer parallel interfaces under different incident angles is carried out. Secondly, combining the preceding two results and courses, electromagnetic scattering from the multilayer random rough surfaces is studied. The computed results are in good agreement with those by using the method of moments (MOM) and reported by some experts. Finally, the random rough sea surface covered by spilling oil or droplets and foams is calculated in detail. Compared with MOM, the new approximate analysis method in the paper can avoid a large matrix inversion, and thus greatly reduce the computation time and improve the computational efficiency.

scholarly journals Interference from the sea surface near the electrostatic system location

2015 ◽  
pp. 70-75
Author(s):  
A. E. Lastavetski
Keyword(s):  
Energy Spectrum ◽  
Electric Field ◽  
Power Spectra ◽  
Spatial Filter ◽  
Sea Surface ◽  
Third Party ◽  
Two Dimensional ◽  
Rough Sea Surface ◽  
Rough Sea ◽  
Electrostatic System

The solution of the problem of the spatial structure of the secondary electric field due to rough sea surface in the field of third-party sources. It is shown that the energy spectrum of two-dimensional components of the electric field is determined as a result of the two-dimensional spatial filter filters the energy spectrum of sea surface height. Shows the frequency characteristics of the spatial filter and temporal power spectra of the components of the electric field when driving electrostatic locator over the sea surface.

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