Spectral reflectance 0.4 to 2.0 microns of silicate rock powders

Adams, John B.; Filice, Alan L.

doi:10.1029/jz072i022p05705

Cited by 246 publications

(101 citation statements)

References 7 publications

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“…In light of the results by Adams and Filice [1967] on albedo variations with changing particle size, this is not surprising. An absolute albedo calibration during the remote-sensing observations would be required in order to apply this class of calibrations.…”

Section: Analytical Groupings and General Trendsmentioning

confidence: 95%

Calibrations of phase abundance, composition, and particle size distribution for olivine‐orthopyroxene mixtures from reflectance spectra

Cloutis¹,

Gaffey²,

Jackowski³

et al. 1986

J. Geophys. Res.

357

511

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Spectral reflectance measurements of characterized (phase abundance, particle size) mixtures of olivine and orthopyroxene were utilized to define the correlations between spectral and albedo parameters of such assemblages and their mineralogical or textural properties. Thirty-three different spectral parameters falling into three general classes (relative or ratioed, absolute or albedo, and wavelength) were investigated for empirical sensitivity to one or more of the mixture properties. Theoretical considerations and previous experimental observations were utilized to understand their functional relationships. The ratio of areas for the 1-and 2-3tm absorption bands is shown to be a sensitive indicator of the olivineorthopyroxene abundance and is very nearly independent of particle size and mineral composition. In conjunction with an abundance determination, the wavelength position of the 1-3tm absorption feature can be utilized to determine the molar iron contents of the olivine and orthopyroxene phases. This calibration is insensitive to particle size but will produce systematic deviations if the phases have significantly different iron contents or if more than a few percent of a clinopyroxene component is present. The spectral albedo in the 0.6-to 0.7-#m region is relatively insensitive to phase abundance and can be used to constrain particle size if phase composition has been determined.

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Section: Analytical Groupings and General Trendsmentioning

confidence: 95%

Calibrations of phase abundance, composition, and particle size distribution for olivine‐orthopyroxene mixtures from reflectance spectra

Cloutis¹,

Gaffey²,

Jackowski³

et al. 1986

J. Geophys. Res.

357

511

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“…We speculate that this signature could be evidence for substantial surface exposure and accumulation of mineral impurities in this region of GrIS. The spectra of most minerals exhibit higher NIR reflectance than bare ice, leading to the potential for a trend toward increased NIR albedo while visible albedo drops with high mineral content (Adams and Filice, 1967;Painter et al, 2003;Bøggild et al, 2010;Casey et al, 2012;Tedesco et al, 2013). The SE GrIS margin shows decreasing NIR albedo and only isolated change in visible wavelengths at the lowest elevations.…”

Section: Impact Of C6 Revision On Scientific Investigation Of Grismentioning

confidence: 99%

Impact of MODIS sensor calibration updates on Greenland Ice Sheet surface reflectance and albedo trends

2017

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Abstract. We evaluate Greenland Ice Sheet (GrIS) surface reflectance and albedo trends using the newly released Collection 6 (C6) MODIS (Moderate Resolution Imaging Spectroradiometer) products over the period [2001][2002][2003][2004][2005][2006][2007][2008][2009][2010][2011][2012][2013][2014][2015][2016]. We find that the correction of MODIS sensor degradation provided in the new C6 data products reduces the magnitude of the surface reflectance and albedo decline trends obtained from previous MODIS data (i.e., Collection 5, C5). Collection 5 and 6 data product analysis over GrIS is characterized by surface (i.e., wet vs. dry) and elevation (i.e., 500-2000 m, 2000 m and greater) conditions over the summer season from 1 June to 31 August. Notably, the visible-wavelength declining reflectance trends identified in several bands of MODIS C5 data from previous studies are only slightly detected at reduced magnitude in the C6 versions over the dry snow area. Declining albedo in the wet snow and ice area remains over the MODIS record in the C6 product, albeit at a lower magnitude than obtained using C5 data. Further analyses of C6 spectral reflectance trends show both reflectance increases and decreases in select bands and regions, suggesting that several competing processes are contributing to Greenland Ice Sheet albedo change. Investigators using MODIS data for other ocean, atmosphere and/or land analyses are urged to consider similar re-examinations of trends previously established using C5 data.

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“…This is a common property of silicate powders discussed by Adams and Filice (1967), who also found that this trend often reverses at large phase angles (powders becoming bluer with increasing phase). There are indications of this happening in some of our samples at phase angles larger than 700.…”

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confidence: 92%

Photometric and polarimetric properties of the bruderheim chondritic meteorite

Egan¹,

Veverka

Noland

et al. 1973

Icarus

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RE -447T.fABSTRACT r Photometric and polarimetric laboratory measurements were made, as a function of phase angle in the U(0.36 im), G(0.541.m) and R(0.67Lm) bands for 0 , 30O and 600 incident illumination on four particle size ranges of Bruderheim, an L6 olivine-hypersthene chondritic meteorite.The four particle size ranges were: 0.25-4.76mm, 0.25-4.76mm coated with <74lm powder, 74-250pm, and < 37pm. In addition, normal reflectance measurments were made in the spectral range from 0.31 to 1.1lm. Comparison with astronomical data reveals that none of the asteroids in the main belt for which adequate observations exist can be matched with Bruderheim, which is representative of the most common meteoritic material encountered by the Earth. However, it appears from the polarization and photometry data that the surface of-the Apollo asteroid Icarus is consistent with an ordinary chondrite composition. ' This suggests the possibility that this material, although common in Earth-crossing orbits, is rare as a surface constituent in the main asteroid belt.ii . I INTRODUCTIONRecently, much astronomical effort has been devoted to the study of the physical properties of asteroid surfaces. This has resulted in an ever growing store of spectral, photometric, and polarimetric data that 'have not been sufficiently complemented by laboratory measurements.Because there are many indirect arguments (Anders, 1964) which indicate that most meteorites are fragments of asteroid bodies, and since McCord, et al. (1970) 'have successfully identified the spectral reflectance curve of one asteroid, Vesta, with that of a basaltic achondrite, laboratory measurments on meteorite samples should prove useful in an intrepretation of asteroid surfaces. We 'have chosen to study the spectral, photometric, and polarimetric properties of the Bruderheim olivine-hypersthene chondrite, which is representative of the most common meteoritic material recovered on Earth (Mason, 1962), and, hence, might also be the most common in interplanetary space. II INSTRUMENTATIONThe Grumman goniometer, designed to measure the polarimetric and photometric properties of samples up to 60mm in diameter, consists of a light source on a 3-meter long arm and a sensor on another 3-meter long arm. The center of rotation of the arms is situated on the average sample surface, and the average normal to the surface lies in the plane defined by the arms.The source is a G-E Type 2331 tungsten lamp, followed by a quartz ground glass diffuser, a Lyot depolarizer, an aperture plate, a 420 cycle, seven 1' bladed chopper, and an 11.4 cm diameter quartz objective lens. This assembly produces a beam collimated to 1°, of uniform brightness to 1 percent or less, with a residual polarization of 0.1 percent or less on the 60mm illuminated sample area. The source arm is ordinarily fixed at an incident illumination angle between 0 and 60 degrees.The sensors used in this investigation were photomultipliers RCA Types 6199 and 7102 with mumetal shields. The sensor arm normally traverses a phase ang...

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Spectral reflectance 0.4 to 2.0 microns of silicate rock powders

Cited by 246 publications

References 7 publications

Calibrations of phase abundance, composition, and particle size distribution for olivine‐orthopyroxene mixtures from reflectance spectra

Calibrations of phase abundance, composition, and particle size distribution for olivine‐orthopyroxene mixtures from reflectance spectra

Impact of MODIS sensor calibration updates on Greenland Ice Sheet surface reflectance and albedo trends

Photometric and polarimetric properties of the bruderheim chondritic meteorite

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