Theoretical model for scattering of radar signals in K<sub><i>u</i></sub>- and C-bands from a rough sea surface with breaking waves

Voronovich, Alexander G.; Zavorotny, Valery U.

doi:10.1080/13616670109409784

Cited by 241 publications

(236 citation statements)

References 33 publications

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“…The details of kernel functions of the integral, B and M , can be found in [25], here, we safely omit it for the sake of brevity. For revised CWM, the integral variables x in Equation (12) should be replaced byx = x + C (x, t), thus the Jacobian J of the transformation from x tox is utilized to accomplish this change of integral variables.…”

Section: Ssa-ii Model For Calculation Of the Doppler Spectrummentioning

confidence: 99%

“…Recently, the second-order small-slope approximation (SSA-II) has been widely applied to evaluate electromagnetic (EM) scattering from sea surfaces with great accuracy [25][26][27][28]. Compared with rigorous numerical methods such as MOMI based on the iteratively solving the magnetic field integral equation with heavy burden on computation time, the analytical model SSA-II is efficient with acceptable accuracy, thus the SSA-II is employed in this study.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Nie¹,

Min²,

Geng³

et al. 2012

PIER

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Abstract-The Doppler spectral characteristics of electromagnetic backscattered echoes from dynamic nonlinear surfaces of finite-depth sea is investigated with the second-order small-slope approximation (SSA-II). The revised nonlinear hydrodynamic choppy wave model (CWM) combining with an experiment-verified shoaling coefficient is utilized to model the finite-depth sea wave profiles, and the simulated surfaces of finite-depth sea show steeper crests and more flat troughs as depth decreases. First, Comparison of the Doppler spectra for linear sea surfaces and nonlinear choppy sea surfaces shows that nonlinear hydrodynamic effect greatly enhances the Doppler shift and the Doppler spectrum bandwidth, and the predicted results agree well with the rigorous numerical model data. The Doppler spectra of backscattered echoes from finite-depth sea with different depths are further evaluated. At small incident angles, the Doppler shifts and the spectra bandwidths are much lower for shallower sea, and the opposite situation can be gradually observed for increased incident angles. This indicates that the nonlinear wave-wave interactions among waves occur more frequently in finite-depth sea and the long waves will be suppressed while shorter wind waves will be boosted in shallower water. Moreover, the dependence of the Doppler spectral characteristics on polarization is also discussed.

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Section: Ssa-ii Model For Calculation Of the Doppler Spectrummentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Nie¹,

Min²,

Geng³

et al. 2012

PIER

View full text Add to dashboard Cite

show abstract

“…Actually, the local fluctuation is always thought as an important feature in ocean SAR imaging. The commonly used method, SSA [21,22], is applicable for a surface RMS slope lower than the slopes and surfaces with gentle slopes. It can readily be applied to surfaces having several scales of roughness.…”

Section: Introductionmentioning

confidence: 99%

Application of Facet Scattering Model in Sar Imaging of Sea Surface Waves With Kelvin Wake

Wang¹,

Min²,

Chen³

et al. 2016

PIER B

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Abstract-The principal purpose of this work is the simulation of the ship wake in Synthetic Aperture Radar (SAR) imaging based on a facet scattering model. The hydrodynamic model of the surface waves mainly considers the Kelvin wake waves and the wind driven waves. For the prediction of radar returns from the composite surface, the semi-deterministic facet scattering model (SDFSM) is proposed, which is verified to have good performance through a comparison with the experiment by SASS-II. Then, the distributions of backscattering normalized radar cross section (NRCS) of facets are investigated for both V V and HH polarizations and characteristics of the wake pattern are shown with good visibility. On the basis of these, an application of velocity bunching (VB) imaging model is presented in detail for the simulation of SAR imaging of sea surface waves with Kelvin wake. Finally, several numerical results provide states of the effects of ship speed, wind speed and the ship sailing direction on the characteristics of Kelvin wake in SAR images. Thus, this simulation may enable us to provide a theoretical basis to the detection of ship wakes.

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“…In the TSM formalism, the large tilting waves are the source of depolarization effects on the Bragg resonant waves. Recent works [Kudryavtsev et al, 2003[Kudryavtsev et al, , 2005Mouche et al, 2006;Voronovich and Zavarotny, 2001] are based on particular statistical decomposition for the NRCS. In such developments, the sea surface is assumed to follow a double structure.…”

Section: Introductionmentioning

confidence: 99%

Importance of the sea surface curvature to interpret the normalized radar cross section

et al. 2007

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[1] Asymptotic models (small perturbation and small slope approximation at first-order, Kirchhoff approximation or two-scale model) used to predict the normalized radar cross section of the sea surface generally fail to reproduce in detail backscatter radar measurements. In particular, the predicted polarization ratio versus incidence and azimuth angles is not in agreement with experimental data. This denotes the inability of these standard models to fully take into account the roughness properties with respect to the sensor's configuration of measurement (frequency, incidence, and polarization). On the basis of particular assumptions, to decompose the scattered electromagnetic field between zones covered with freely propagating waves and others where roughness and slopes are enhanced, recent works were able to match observations. In this paper, we do not assume such a decomposition but study the latest improvements obtained in the field of approximate scattering theories of random rough surfaces using the local and resonant curvature approximations. These models are based on an extension of the Kirchhoff Approximation up to first order to relate explicitly the curvature properties of the sea surface to the polarization strength of the scattered electromagnetic field. Consistency with previous approaches is discussed. As shown, dynamically taking into account the sea surface curvature properties of the surface is crucial to better interpret normalized radar cross-section and polarization ratio sensitivities to both sensor characteristics and geophysical environment conditions. The proposed developments, termed the Resonant Curvature Approximation (RCA), are found to reproduce experimental data versus incidence angle and azimuth direction. The polarization sensitivity to the wind direction and incidence angle is largely improved. Finally, Gaussian statistical assumption adopted to derive the analytical expression of the normalized radar cross section is also discussed. In particular, the third-order cumulant function is shown to better reproduce the second-order up-/down-wind azimuth modulation. The proposed developments appear very promising for improvement of our understanding and analysis of both sea surface radar backscatter and Doppler signals.Citation: Mouche, A. A., B. Chapron, N. Reul, D. Hauser, and Y. Quilfen (2007), Importance of the sea surface curvature to interpret the normalized radar cross section,

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Theoretical model for scattering of radar signals in K_u- and C-bands from a rough sea surface with breaking waves

Cited by 241 publications

References 33 publications

Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Application of Facet Scattering Model in Sar Imaging of Sea Surface Waves With Kelvin Wake

Importance of the sea surface curvature to interpret the normalized radar cross section

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Theoretical model for scattering of radar signals in Ku- and C-bands from a rough sea surface with breaking waves

Cited by 241 publications

References 33 publications

Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Application of Facet Scattering Model in Sar Imaging of Sea Surface Waves With Kelvin Wake

Importance of the sea surface curvature to interpret the normalized radar cross section

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Theoretical model for scattering of radar signals in K_u- and C-bands from a rough sea surface with breaking waves