Numerical study on the along-track interferometric radar imaging mechanism of oceanic surface currents

Romeiser, Roland; Thompson, D. R.

doi:10.1109/36.823940

Cited by 235 publications

(163 citation statements)

References 23 publications

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“…Two data sets as references are quoted here. One is the data set of Doppler simulations based on rigorous MOMI model by Toporkov and Brown [15], and the other is based on the TSM combined with the modulation transfer function (MTF) technique by Romeiser and Thompson [33], which has been demonstrated to be qualitatively consistent with the experimental results and other numerical approaches.…”

Section: Numerical Resultssupporting

confidence: 55%

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: Numerical Resultssupporting

confidence: 55%

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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“…The simulations were configured by input files so that the second module (M4Sr320) used the wave spectrum produced by the M4Sw320 module, along with sensor (frequency, polarization, platform altitude and velocity) and imaging (incidence angle, look direction, and platform heading) attributes, to compute NRSC matrices. This module, also known as the Radar Module, also incorporates the contributions from the Improved Composite Surface Model THOMPSON, 2000), as well as from artifacts generated by the imaging mechanism. The M4S modelling procedures are summarized in Figure 4.…”

Section: Shear and Divergence Of Surface Currents At The Bc Frontmentioning

confidence: 99%

“…The theoretical basis of the M4S model is presented in , THOMPSON (2000). The M4S model employs a set of numerical routines that simulate microwave radar imaging of ocean surface features that may be either associated with or modulated by a surface current field, as well as by variations of the ocean surface wind field.…”

Section: M4s -The Numerical Model To Simulate Sar Microwave Ocean Imamentioning

confidence: 99%

“…Recent models, such as the M4S and the Radar Imaging Model (RIM) are now able to provide very realistic simulation results. The present study employed the M4S model developed by , ROMEISER and THOMPSON (2000). This model is mostly based on the Bragg backscattering mechanism and the Weak Interaction theories (LONGUET-HIGGINS; STEWART, 1964;WHITHAM, 1965;BRETHERTON, 1971); it is also able to represent the geometric modulations caused by the tilt of illuminated facets and range variations, the hydrodynamic modulation of Bragg waves caused by longer waves, and it also includes the "velocity bunching" mechanism .…”

Section: Introductionmentioning

confidence: 99%

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Numerical simulations of SAR microwave imaging of the Brazil current surface front

Macedo

Lorenzzetti

2015

Braz. j. oceanogr.

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This paper analyzes the hydrodynamic and atmospheric instability modulation mechanisms which influence the Brazilian Current's (BC) thermal front signature in Synthetic Aperture Radar (SAR) images. Simulations were made using the M4S SAR imaging model. Two SAR images of the Brazilian Southeastern Coast depicting the BC's thermal front were selected including a VV (ASAR/Envisat) and a HH polarization (RADARSAT-1) image. Conditions of current shear and divergence were reproduced for the fronts imaged, using in situ (Acoustic Doppler Current Profilers) current velocities. Wind velocity fields were simulated based on QuikSCAT data. Results showed that SAR imaging of the BC front may be influenced both by atmospheric instabilities and hydrodynamic modulations. The first mechanism prevailed on the RADARSAT image and the latter on the ASAR/Envisat image. When atmospheric instabilities prevailed, the contribution of shear and divergence was almost negligible. When hydrodynamic modulations prevailed, a better agreement between the simulated responses and SAR image responses was obtained by inforcing a reduction of 88% in the relaxation rate, and higher divergence values, of the order of 10 -4 s -1 . Results indicate that, for some specific cases, local increases in shear and divergence may allow the detection of the BC thermal front. AbstrAct

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“…These orbital velocities are amplified by shallow bathymetric features and might reach tens of cm/s or even m/s in coastal areas. Tsunami orbital velocities might be detected by along-track interferometric SAR systems (Romeiser, 2000) and HF surface wave radars (e.g. Lipa, 2006;Anderson, 2008).…”

Section: Tsunami Orbital Velocitiesmentioning

confidence: 99%

Concept study of radar sensors for near-field tsunami early warning

Börner

Galletti

Marquart

et al. 2010

Nat. Hazards Earth Syst. Sci.

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Abstract. Off-shore detection of tsunami waves is a critical component of an effective tsunami early warning system (TEWS). Even more critical is the off-shore detection of local tsunamis, namely tsunamis that strike coastal areas within minutes after generation. In this paper we propose new concepts for near-field tsunami early detection, based on innovative and up-to-date microwave remote sensing techniques. We particularly introduce the NESTRAD (NEar-Space Tsunami RADar) concept, which consists of a real aperture radar accommodated inside a stationary stratospheric airship providing continuous monitoring of tsunamigenic oceanic trenches.

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Numerical study on the along-track interferometric radar imaging mechanism of oceanic surface currents

Cited by 235 publications

References 23 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

Numerical simulations of SAR microwave imaging of the Brazil current surface front

Concept study of radar sensors for near-field tsunami early warning

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