Bi-directional reflectance measurements of closely packed natural and prepared particulate surfaces

Zhang, Hao; Voss, Kenneth J.

doi:10.1007/978-3-540-48546-9_8

Cited by 4 publications

(4 citation statements)

References 35 publications

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“…2. With a sample layer thickness of 3 mm, radiative transfer computations [27][28][29] show that for the wavelength spans in this study these particulate layers have optical thickness values large enough to have their reflectance not affected by any substrate retro-reflections. All measured data presented here are reflectance relative to Spectralon with nominal 99% reflectance, or R s in Eq.…”

Section: Laboratory Measurementsmentioning

confidence: 72%

“…1 is the 8°-HR and the biconical reflectance measured under the EasiDiff geometry should be closer to a 47°-incidence and 47°-viewing bidirectional reflectance. These two quantities should have different reflectance values and band depths because of the directional effects of the Spectralon especially under oblique incidences (e.g [28].). Because few goniometers can accurately measure the absolute bidirectional reflectance above 1.5 μm and thus the real r c data containing the 2.1 μm peak under the EasiDiff geometry are not available.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Spectralon absorption on reflectance spectra of typical planetary surface analog materials

Zhang¹,

Yang²,

Jin³

et al. 2014

Opt. Express

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Acquiring accurate visible and near-infrared (VisNIR) reflectance values of atmosphereless celestial bodies is very important in inferring the physical and geological properties of their surficial materials. When a calibration target with inherent non-trivial absorption features is used, the calibrated reflectance would essentially always contain spurious spectral features and the spectroscopic data may easily be misinterpreted if the artifact is not properly taken care of. We demonstrate with laboratory reflectance measurements that the VisNIR spectra of three typical planetary surface analog materials, lunar simulant JSC-1A, olivine and pyroxene grains, have an artificial peak at 2.1 µm when Spectralon-type plaque made of polytetrafluoroethylene is used as the calibration target in the NIR region. The degree of severity of this artifact is dependent on the strength of the 2.0 µm absorption feature of the mineral. Empirical methods are proposed to remove this artifact to bring the spectra close to that calibrated by a gold mirror which does not have any conspicuous absorption features in the NIR region. The correction methods may be applied to reflectance data acquired by the VisNIR imaging spectrometer onboard the Yutu Rover of the Chinese Chang'E 3 lunar mission which employed an onboard Spectralon-type calibration target.

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Section: Laboratory Measurementsmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Effects of Spectralon absorption on reflectance spectra of typical planetary surface analog materials

Zhang¹,

Yang²,

Jin³

et al. 2014

Opt. Express

Self Cite

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show abstract

“…In particular, the knowledge of scattering properties of densely packed particulate ice is needed for the interpretation of radar observations of terrestrial ice sheets [1], the Moon [2], Mercury [3], Galilean satellites of Jupiter [4], and Saturn's rings [5]. Similarly, definitive interpretation of bidirectional remote-sensing observations of snow, soil, desert, and regolith surfaces at visible wavelengths [6][7][8][9][10] requires an accurate scattering theory directly based on the Maxwell equations.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic scattering by densely packed particulate ice at radar wavelengths: exact theoretical results and remote-sensing implications

Mishchenko

Liu

2009

Appl. Opt.

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We use the numerically exact superposition T-matrix method to compute electromagnetic scattering characteristics of a macroscopic volume of a discrete random medium filled with wavelength-sized spherical particles with a refractive index typical of water ice at centimeter wavelengths. Our analysis demonstrates relative strengths of various optical observables in terms of their potential remote-sensing content. In particular, it illustrates the importance of accounting for the forward-scattering interference effect in the interpretation of occultation measurements of planetary rings. We show that among the most robust indicators of the amount of multiple scattering inside a particulate medium are the cross-polarized scattered intensity, the same-helicity scattered intensity, and the circular polarization ratio. We also demonstrate that many predictions of the low-packing-density theories of radiative transfer and coherent backscattering are applicable, both qualitatively and semi-quantitatively, to densely packed media.

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“…The samples used in the laboratory polarization measurements mentioned above are mostly fine lunar regolith and planetary surface analog materials having particle sizes of several or a few tens of micrometers. In our measurements of the bi-directional reflectance distribution function (BRDF) of both natural benthic sediments and prepared particulate layers [18,19], we have found significant hotspots in most of the millimeter-sized samples [20,21]. Although in underwater remote sensing it would be difficult to acquire scattering information within 2 phase angle (except in the case of lidar measurements), given the CBS and SHOE characterization efforts summarized above, we wanted to answer the following questions; is negative polarization observable in these millimeter-sized benthic sediment grains?…”

Section: Introductionmentioning

confidence: 99%

Bidirectional reflectance and polarization measurements on packed surfaces of benthic sediments and spherical particles

Zhang¹,

Voss²

2009

Opt. Express

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Laboratory bidirectional reflectance and polarization measurements were carried out on packed layers of both natural sediments and manufactured spherical particles. The results indicate that among the natural sediments showing a strong backscattering peak ("hotspot"), the rough platelets are the only sediments with a negative polarization effect. Measurements of circular and linear polarization ratios indicate that both smooth ooids and rough platelets are strongly depolarizing. Measurements of perfect spherical grains show both negative polarization and strong backscattering as a remnant of the single scattering process.

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Bi-directional reflectance measurements of closely packed natural and prepared particulate surfaces

Cited by 4 publications

References 35 publications

Effects of Spectralon absorption on reflectance spectra of typical planetary surface analog materials

Effects of Spectralon absorption on reflectance spectra of typical planetary surface analog materials

Electromagnetic scattering by densely packed particulate ice at radar wavelengths: exact theoretical results and remote-sensing implications

Bidirectional reflectance and polarization measurements on packed surfaces of benthic sediments and spherical particles

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