Polarimetric thermal emission from rough ocean surfaces

Johnson, Joel T.; Kong, Jin Au; Shin, R.T.; Yueh, Simon; Nghiem, S. V.; Kwok, R.

doi:10.1163/156939394x00803

Cited by 18 publications

(13 citation statements)

References 10 publications

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“…The response of U B to surface slope, as indicated by higher U B values for larger surface heights, is demonstrated in Figure 11. This response has been observed in the literature for 1-D periodic surfaces [11,16]. Surfaces with heights less than 0.25λ and maximum slopes consequently less than 0.08 are seen to produce negligible U B emission.…”

Section: Pyramidal Surface Thermal Emissionsupporting

confidence: 76%

“…Responses to polar observation angle similar to those in Figure 12 have been observed for 1-D periodic surfaces [11]. However, simulations in the literature with much higher, ocean like dielectric constant media show smaller variations in U B with polar observation angle in this range [16]. Also, V B is observed to show some response to polar observation angle, although it is quite small.…”

Section: Pyramidal Surface Thermal Emissionsupporting

confidence: 75%

“…However, these six sets of equations are restricted to four by the divergenceless condition of plane wave fields. Using the x and y components of these equations and substituting in the Fourier series expansions (15)(16)(17)(18) results in the following matrix equation:…”

Section: Formulation and Numerical Methodsmentioning

confidence: 99%

“…Models for one dimensional periodic surface scattering have found application in a wide range of areas, ranging from optical grating design [8] to the prediction of wave propagation over the ocean [10]. In a more recent application, theories and experiments involving passive remote sensing of one dimensional periodic surfaces [11][12][13][14][15][16] have conclusively demonstrated the existence of a third Stokes parameter component of the thermal emission, U B . Assumed to be non-zero only in polarimetric passive remote sensing, U B is known to respond to the azimuthal anisotropy of the medium under view [17] and thus is currently being investigated for application to remote sensing of wind direction over the ocean [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…Since the region below the surface profile is considered to be a half space in this paper, use of a surface integral equation technique as opposed to the volume integral equations of [22] results in a more efficient solution. Although the limitations of the EBC method for surfaces with deep corrugations are well known [23], previous one dimensional periodic surface studies showed the EBC to perform efficiently for non-steep surfaces when compared to a method of moments approach [16]. Use of the EBC method for two dimensional surface profiles is motivated by the fact that computational requirements are much greater than in the one dimensional case, so that efficiency becomes an even more important issue if a thorough study is to be performed.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Scattering and Thermal Emission from a Two Dimensional Periodic Surface

Johnson¹,

Kong²

1997

PIER

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Section: Pyramidal Surface Thermal Emissionsupporting

confidence: 76%

Section: Pyramidal Surface Thermal Emissionsupporting

confidence: 75%

Section: Formulation and Numerical Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Scattering and Thermal Emission from a Two Dimensional Periodic Surface

Johnson¹,

Kong²

1997

PIER

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Computational Electromagnetic Scattering Models for Microwave Remote Sensing

Ding

Tsang

2005

Encyclopedia of RF and Microwave Engineering

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Modeling of electromagnetic wave propagation and scattering in random media play an important role in geoscience and remote sensing research. Considerable efforts have been made to elucidate and understand the wave interaction processes involved in such problems, and various models have been developed for microwave active and passive remote sensing applications. With the rapid advances in computer technology and fast computational electromagnetic algorithms, numerical simulations of scattering by random media allow us to solve Maxwell's equations exactly without the limitations of approximate analytical models. The numerical models can provide a valuable means for evaluating the validity regimes of analytical scattering theories; in addition, they can potentially aid in the future development of extended analytical models. In this article, updated developments in the numerical scattering models for discrete random scatterers are presented, with emphasis on the applications of microwave remote sensing in snowcover, seafoam, and vegetation canopy. The frequency dependence of scattering by dense media at microwave frequencies is the first numerical model described, which is an important topic because multifrequency measurements are usually used in remote sensing applications. The approach used is based on the Monte Carlo simulations where the three‐dimensional solutions of Maxwell's equations are solved. The properties of absorption, scattering, and extinction are calculated for dense media consisting of sticky and nonsticky particles. Numerical solutions of Maxwell's equations indicate that the frequency dependence of densely packed sticky small particles is much weaker than that of independent scattering. Numerical results are illustrated using parameters of snow in microwave remote sensing. Comparisons are made with extinction measurements as a function of frequency. Polarimetric microwave emissions form foam‐covered ocean surfaces are studied by modeling foam as densely packed air bubbles coated with thin seawater. The absorption, scattering, and extinction coefficients are computed from the Monte Carlo solutions of Maxwell's equations for a collection of coated particles. These quantities are then applied in the dense media radiative transfer theory to calculate the polarimetric microwave emissivities of ocean surfaces with foam cover. The theoretical results of Stokes brightness temperatures with typical parameters of foam in passive remote sensing at 10.8 and 36.5 GHz are illustrated and compared with experimental measurements. It follows by describing an efficient computational model based on the sparse matrix iterative approach (SMIA) for tree scattering at VHF/UHF frequencies. The method of moments is applied to solve the volume integral equation for the tree scattering signatures. The SMIA decomposes the impedance matrix into a sparse matrix for the near interactions, and a complementary matrix for the far interactions of the tree structure. Solutions obtained from the SMIA method agree very well with the solutions obtained using extract matrix inversion and the conjugate gradient method (CGM). The key feature of the SMIA approach is that very little iteration is required to obtain convergent solutions; compared to the CGM, the SMIA approach may reduce the number of iterations by a factor of >100. The UV multilevel partitioning (UV‐MLP) method is also presented for solving the general volume scattering problems. The method consists of setting up a rank table of transmitting and receiving block sizes and their separations. The table can be set up speedily using coarse–coarse sampling. For a specific scattering problem with given geometry, the scattering structure is partitioned into multilevel blocks. By looking up the rank in the pre‐determined table, the impedance matrix for a given transmitting and receiving block is expressed by a product of U and V matrices. We demonstrate the method for two‐dimensional volume scattering by discrete scatterers. Multiple scattering is cast into the Foldy–Lax equations of partial waves. We show that the UV decomposition can be applied directly to the impedance matrix of partial waves of higher order than the usual lowest‐order Green function. Numerical results are illustrated for randomly distributed cylinders with a diameter of 1 wavelength. For scattering by 1024 cylinders on a single PC processor with 2.6 GHz CPU and 2 GB memory, only 14 CPU minutes is needed to obtain the numerical solution and for 4096 cylinders, only 7.34 s is needed for one matrix–vector multiplication.

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Rough Surface Scattering: Numerical Simulations and Applications in Microwave Remote Sensing

Xia

Tsang

et al. 2005

Encyclopedia of RF and Microwave Engineering

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In this article we present rough‐surface bistatic scattering and emission based on NMM3D (numerical Maxwell model using 3D simulations). Results are computed using the method of sparse matrix canonical grid with RWG (Rao–Wilton–Glisson) basis functions. Results are illustrated for active and passive microwave remote sensing of soil moisture and ocean. We also describe recent numerical simulation techniques of the single integral equation and the multilevel UV method in rough surface scattering.

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Polarimetric thermal emission from rough ocean surfaces

Cited by 18 publications

References 10 publications

Scattering and Thermal Emission from a Two Dimensional Periodic Surface

Scattering and Thermal Emission from a Two Dimensional Periodic Surface

Computational Electromagnetic Scattering Models for Microwave Remote Sensing

Rough Surface Scattering: Numerical Simulations and Applications in Microwave Remote Sensing

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