Numerical calculations of radar scattering from sharply peaked ocean waves

Lyzenga, David R.; Ericson, E.A.

doi:10.1109/36.662744

Cited by 19 publications

(4 citation statements)

References 25 publications

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“…Some analytical and numerical solutions of the scattering problem have been proposed, in the past. Among these studies we mention the recent investigations by Lyzenga and Ericson [1998] of microwave diffraction on a wedge corresponding to a steep Stokes wave. It was shown that the backscattering power drops quickly when the curvature radius r c of the crest increases; at k r r c > 1, the return signal becomes insignificant.…”

Section: Radar Backscattering: Governing Equationsmentioning

confidence: 99%

A semiempirical model of the normalized radar cross‐section of the sea surface 1. Background model

Kudryavtsev

Hauser²,

Caudal³

et al. 2003

J. Geophys. Res.

250

388

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[1] Multiscale composite models based on the Bragg theory are widely used to study the normalized radar cross-section (NRCS) over the sea surface. However, these models are not able to correctly reproduce the NRCS in all configurations and wind wave conditions. We have developed a physical model that takes into account, not only the Bragg mechanism, but also the non-Bragg scattering mechanism associated with wave breaking. A single model was built to explain on the same physical basis both the background behavior of the NRCS and the wave radar Modulation Transfer Function (MTF) at HH and VV polarization. The NRCS is assumed to be the sum of a Bragg part (two-scale model) and of a non-Bragg part. The description of the sea surface is based on the short wind wave spectrum (wavelength from few millimeters to few meters) developed by Kudryavtsev et al. [1999] and wave breaking statistics proposed by Phillips [1985]. We assume that non-Bragg scattering is supported by quasi-specular reflection from very rough wave breaking patterns and that the overall contribution is proportional to the white cap coverage of the surface. A comparison of the model NRCS with observations is presented. We show that neither pure Bragg nor composite Bragg model is able to reproduce observed feature of the sea surface NRCS in a wide range of radar frequencies, wind speeds, and incidence and azimuth angles. The introduction of the non-Bragg part in the model gives an improved agreement with observations. In Part 2, we extend the model to the wave radar MTF problem.

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Section: Radar Backscattering: Governing Equationsmentioning

confidence: 99%

A semiempirical model of the normalized radar cross‐section of the sea surface 1. Background model

Kudryavtsev

Hauser²,

Caudal³

et al. 2003

J. Geophys. Res.

250

388

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show abstract

“…A number of potential scattering mechanisms from steep and/or breaking waves have been described in the literature. The mechanisms likely to be of highest importance at intermediate grazing angles are quasi-specular scattering from the forward faces of steep breaking or near-breaking waves [23], [14], edge diffraction from sharply peaked wave crests [24]- [26], and Bragg scattering from the increased surface roughness generated during the breaking process [23], [27].…”

Section: Breaking-wave Detectionmentioning

confidence: 99%

Comparison of radar and video observations of shallow water breaking waves

Haller

Lyzenga²

2003

IEEE Trans. Geosci. Remote Sensing

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Simultaneous microwave and video measurements of shallow water breaking waves are presented. A comparison of the data from the two sensors shows that short-duration spikes in the measured X-band radar cross section are highly correlated with the presence of breaking waves in the video imagery. In addition, the radar backscatter from shallow water breaking events is responsible for 40% to 50% of the total cross section, which is a much larger contribution than typically observed for deepwater breaking events. Based on estimates of the area of individual breaking regions determined from digitized video images, the radar cross section per unit area of the turbulent breaking region is shown to be well approximated by a value of 1.9 dB at 31 grazing. Finally, there are some differences between the radar and video signals that suggest that microwave radar may be less sensitive than video techniques to relict foam not associated with active wave breaking. In general, the results indicate that radar is a very good detector of shallow water breaking waves and suggest that radar can be used for the measurement of the spatial and temporal variations of wave breaking.

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“…Since it was observed that the sharp wave crests is wedge-shaped [22,23], the dihedral wedge was used to approximately simulate the breaking waves. In addition, the geometric parameters on the scattering were discussed with numerical methods [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Composite Scattering of Ship on Sea Surface With Breaking Waves

Min¹,

Luo²,

Luo³

et al. 2012

PIER

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Abstract-The composite backscattering of the ship model on sea surface is investigated with the spilling breaking waves and ship bow waves. The spilling breakers are approximately modeled with the wedge-like waves, and the ship bow waves are simulated based on the Kelvin model. With the modified four-path model, each scattering component is evaluated with the high frequency approximation methods for the total composite scattering. Due to the volume scattering, the composite scattering at large incidence angles is strongly enhanced by the non-Bragg scattering. The relationship of the composite scattering and the ship motion is analyzed. The numerical results of sea surface scattering agree with the measured data well, and the complex physical mechanism of the low-grazing-angle composite scattering is explicitly evaluated in this paper.

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Numerical calculations of radar scattering from sharply peaked ocean waves

Cited by 19 publications

References 25 publications

A semiempirical model of the normalized radar cross‐section of the sea surface 1. Background model

A semiempirical model of the normalized radar cross‐section of the sea surface 1. Background model

Comparison of radar and video observations of shallow water breaking waves

Composite Scattering of Ship on Sea Surface With Breaking Waves

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