Mathematical and Physical Modelling of Microwave Scattering and Polarimetric Remote Sensing

Kozlov, Anatoly Ivanovich; Ligthart, L.P.; Logvin, A.I.; Besieris, Ioannis M.; Pusone, E. G.

doi:10.1007/0-306-48091-3

Cited by 23 publications

(9 citation statements)

References 76 publications

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“…In order to model the backscatter from large-scale erg surface features (i.e., dunes), we adopt the general scattering model presented in [16]. The average copolar scattering coefficient is expressed as a function of and given by (3) where is the generic response from the target surface as a function of azimuth angle and local incidence angle .…”

Section: A Rough Facet Modelmentioning

confidence: 99%

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Microwave backscatter modeling of erg surfaces in the Sahara desert

Stephen

Long

2005

IEEE Trans. Geosci. Remote Sensing

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Abstract-The Sahara desert includes large expanses of sand dunes called ergs. These dunes are formed and constantly reshaped by prevailing winds. Previous study shows that Saharan ergs exhibit significant radar backscatter ( ) modulation with azimuth angle ( ). We use measurements observed at various incidence angles and from the NASA Scatterometer (NSCAT), the SeaWinds scatterometer, the ERS scatterometer (ESCAT), and the Tropical Rainfall Measuring Mission's Precipitation Radar to model the response from sand dunes. Observations reveal a characteristic relationship between the backscatter modulation and the dune type, i.e., the number and orientation of the dune slopes. Sand dunes are modeled as a composite of tilted rough facets, which are characterized by a probability distribution of tilt with a mean value, and small ripples on the facet surface. The small ripples are modeled as cosinusoidal surface waves that contribute to the return signal at Bragg angles only. Longitudinal and transverse dunes are modeled with rough facets having Gaussian tilt distributions. The model results in a response similar to NSCAT and ESCAT observations over areas of known dune types in the Sahara. The response is high at look angles equal to the mean tilts of the rough facets and is lower elsewhere. This analysis provides a unique insight into scattering by large-scale sand bedforms.

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Section: A Rough Facet Modelmentioning

confidence: 99%

“…The local normal vector and incidence wave vector are (14) (15) The slopes of the surface in and directions are given by (16) (17) where the inverse relationship is given by (18) (19) We define the local coordinate system ( , , ) as …”

Section: A Local Incidence and Azimuth Anglesmentioning

confidence: 99%

Microwave backscatter modeling of erg surfaces in the Sahara desert

Stephen

Long

2005

IEEE Trans. Geosci. Remote Sensing

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“…Therefore, at large incident angles, the surface elements of large-scale components can no longer be considered as planes, but should be treated as curved surfaces. Finally, based on the scattering theory of facet in [42], the phase modified (k 1 ·r+ϕ) field-based scattering model is proposed. The curvature modified factor (c pp ) and the shadowing function (S(v)) are introduced, the scattering field of the facet-based two-scale model is obtained by…”

Section: The Modified Facet-based Two-scale Modelmentioning

confidence: 99%

“…k 1 ·r+ϕ is the phase modified. Hypothesis the large-scale roughness waves are geometrically illustrated by a discrete set of ζ (ρ, t), then γ x = ∂ζ/∂x and γ y = ∂ζ/∂y are the corresponding slopes.ϕ = ξ·k 1 ·(∆x,∆y,(γ x ·∆x + γ y ·∆y)), −1/2 ≤ ξ ≤ 1/2, the specific theory is in [42]. In each facet, KA is adopted to calculate the specular scattering, and IEM computes the diffusion scattering.…”

Section: The Modified Facet-based Two-scale Modelmentioning

confidence: 99%

A Modified Model for Electromagnetic Scattering of Sea Surface Covered with Crest Foam and Static Foam

Zhao

et al. 2020

Remote Sensing

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With the increase of sea surface wind speed, whitecaps will appear on the sea surface. Generally, for Electromagnetic (EM) scattering of the foam-covered sea surface, medium-scale waves are used to replace the breaking waves of the real sea surface. Another treatment in computation is to adopt one of the whitecap coverages and fixed foam layer thickness. In fact, the evolution process of a breaking wave goes through two stages: stage A (crest foam) and stage B (static foam). In this paper, a geometric model of the sea surface covered with crest foam and static foam is established. The coverage ratio of stage A and stage B is proposed for the first time for a given sea state. In addition, different foam layer thickness distributions in each foam for various wind speeds are also considered. Based on the facet scattering theory of sea surface, this paper adopts the modified facet-based scattering model to deal with the scattering contribution of the sea surface and the effect of foam. Finally, in order to verify the accuracy of the geometric modeling and the scattering model of the sea surface, the EM backscattering of sea surface under different sea states are calculated. Simulation results show that the results of the proposed model are more consistent with the measured data than the results of the sea surface covered with individual crest foam or the sea surface covered with individual static foam.Carlo method to study the EM scattering of dense foam on the sea surface. In addition, Kalmykov [10] pointed out that the wedge model could be able to simulate the crest breaking wave, which would enhance the polarization ratio. Lyzenga et al. [11] calculated the EM scattering of the wedge model to modify the scattering coefficient of the sea surface. Churyumov [12] regarded the medium-scale breaking wave as scatterers capable of generating non-Bragg scattering. Kudryavtsev et al. [13,14] established a semi-empirical model to modify the scattering coefficient of the sea surface by considering the breaking wave and whitecap coverage. West and Zhao [15] adopted a Multi-Level Fast Multipole Algorithm (MLFMA) to calculate the EM scattering of the LONGTANK wave model, and the results illustrated the high polarization ratio and sea spike. Li et al. [16] established a 3-D scattering model based on the wedge model and the capillary wave modification facet scattering model (CWMFSM), which to some extent interprets the "super events" under high sea conditions. The above works almost adopt the medium-scale waves or a single breaking wave model to replace the real breaking wave of the sea surface. Thus, from the geometric modeling of the foam-covered sea surface, they do not accord with the real situation of the sea surface.As a matter of fact, in [17][18][19], in terms of the time evolution of whitecap, the process of a whitecap goes through two stages: stage A and stage B. Stage A is the growth process, called crest foam, located on the breaking wave. It is produced by a combination of active breaking waves and dragged air. Stage...

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“…Design of (tracking) radar relies on the time correlation properties of the received scattered signals. Regarding coherence, the correlation time cor τ of the received signals for narrow beam and radial speed measurements is given by [2]:…”

Section: Design Considerationmentioning

confidence: 99%

Radar objects detection and imaging for ground-based vehicle collision avoidance: computer simulation results and safety aspects

Pusone

Terzi

Coccia

et al. 2007

2007 International Conference on Electromagnetics in Advanced Applications

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The scope of this paper is to illustrate a new concept of a multi-sensor system for obstacle detection, and collision avoidance by controlling the motion of the vehicle traveling at very high speed regimes, of the order of 250 km/h. The paper illustrates the primary requirement of safety for the vehicle and the passengers and presents the effects of relative motion at such high speeds on radar data quality. A new mathematical model is described for calculating the effects of scintillation on detection range and Doppler velocity. Results indicate large spread around the expected values of range and Doppler depending on propagation and type of fluctuation of the signal. For improved obstacle detection and tracking is concluded that the effects of fluctuations of front radar measurements need to be compensated by measurements from a reference sensor on board, for example a rear sensor.

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Mathematical and Physical Modelling of Microwave Scattering and Polarimetric Remote Sensing

Cited by 23 publications

References 76 publications

Microwave backscatter modeling of erg surfaces in the Sahara desert

Microwave backscatter modeling of erg surfaces in the Sahara desert

A Modified Model for Electromagnetic Scattering of Sea Surface Covered with Crest Foam and Static Foam

Radar objects detection and imaging for ground-based vehicle collision avoidance: computer simulation results and safety aspects

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