Roger N Clark (Former Employee)
Science and Products
Filter Total Items: 75
Photometric changes on Saturn's Titan: Evidence for active cryovolcanism Photometric changes on Saturn's Titan: Evidence for active cryovolcanism
We report infrared spectrophotometric variability on the surface of Saturn's moon Titan detected in images returned by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Saturn Orbiter. The changes were observed at 7°S, 138°W and occurred between October 27, 2005 and January 15, 2006. After that date the surface was unchanged until the most recent observation, March...
Authors
Robert M. Nelson, Lucas W. Kamp, Rosaly Lopes, Dennis L. Matson, Randolph L. Kirk, Bruce W. Hapke, Stephen D. Wall, Mark D. Boryta, Frank E. Leader, William D. Smythe, Karl L. Mitchell, Kevin H. Baines, Ralf Jaumann, Christophe Sotin, Roger N. Clark, Dale P. Cruikshank, Pierre Drossart, Jonathan I. Lunine, Michel Combes, Giancarlo Bellucci, Jean-Pierre Bibring, Fabrizio Capaccioni, Pricilla Cerroni, Angioletta Coradini, Vittorio Formisano, Gianrico Filacchione, Yves Langevin, Thomas B. McCord, Vito Mennella, Philip D. Nicholson, Bruno Sicardy, Patrick G.J. Irwin, John C. Pearl
Opaline silica in young deposits on Mars Opaline silica in young deposits on Mars
High spatial and spectral resolution reflectance data acquired by the Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument reveal the presence of H2O- and SiOH-bearing phases on the Martian surface. The spectra are most consistent with opaline silica and glass altered to various degrees, confirming predictions based on geochemical...
Authors
Ralph E. Milliken, Gregg A. Swayze, Raymond E. Arvidson, Janice L Bishop, Roger N. Clark, Bethany L. Ehlmann, Robert O. Green, John P. Grotzinger, R.V. Morris, Scott L. Murchie, John F. Mustard, C. Weitz
USGS Digital Spectral Library splib06a USGS Digital Spectral Library splib06a
Introduction We have assembled a digital reflectance spectral library that covers the wavelength range from the ultraviolet to far infrared along with sample documentation. The library includes samples of minerals, rocks, soils, physically constructed as well as mathematically computed mixtures, plants, vegetation communities, microorganisms, and man-made materials. The samples and...
Authors
Roger N. Clark, Gregg A. Swayze, Richard A. Wise, K. Eric Livo, Todd M. Hoefen, Raymond F. Kokaly, Stephen J. Sutley
Correlations between Cassini VIMS spectra and RADAR SAR images: Implications for Titan's surface composition and the character of the Huygens Probe Landing Site Correlations between Cassini VIMS spectra and RADAR SAR images: Implications for Titan's surface composition and the character of the Huygens Probe Landing Site
Titan's vast equatorial fields of RADAR-dark longitudinal dunes seen in Cassini RADAR synthetic aperture images correlate with one of two dark surface units discriminated as “brown” and “blue” in Visible and Infrared Mapping Spectrometer (VIMS) color composites of short-wavelength infrared spectral cubes (RGB as 2.0, 1.6, 1.3 μm). In such composites bluer materials exhibit higher...
Authors
Laurence A. Soderblom, Randolph L. Kirk, Jonathan I. Lunine, Jeffrey A. Anderson, Kevin H. Baines, Jason W. Barnes, Janet M. Barrett, Robert H. Brown, Bonnie J. Buratti, Roger N. Clark, Dale P. Cruikshank, Charles Elachi, Michael A. Janssen, Ralf Jaumann, Erich Karkoschka, Stéphane Le Mouélic, Rosaly Lopes, Ralph D. Lorenz, Thomas B. McCord, Philip D. Nicholson, Jani Radebaugh, Bashar Rizk, Christophe Sotin, Ellen R. Stofan, Tracie L. Sucharski, Martin G. Tomasko, Stephen D. Wall
Near-infrared spectral mapping of Titan's mountains and channels Near-infrared spectral mapping of Titan's mountains and channels
We investigate the spectral reflectance properties of channels and mountain ranges on Titan using data from Cassini's Visual and Infrared Mapping Spectrometer (VIMS) obtained during the T9 encounter (26 December 2005). We identify the location of channels and mountains using synthetic aperture radar maps obtained from Cassini's RADAR instrument during the T13 (30 April 2006) flyby...
Authors
Jason W. Barnes, Jani Radebaugh, Robert H. Brown, Steve Wall, Laurence A. Soderblom, Jonathan I. Lunine, Devon M. Burr, Christophe Sotin, Stephane Le Mouelic, Sebastien Rodriguez, Bonnie J. Buratti, Roger N. Clark, Kevin H. Baines, Ralf Jaumann, Philip D. Nicholson, Randolph L. Kirk, Rosaly Lopes, Ralph D. Lorenz, Ken Mitchell, Charles A. Wood
Spectroscopic and x-ray diffraction analyses of asbestos in the World Trade Center dust: Asbestos content of the settled dust Spectroscopic and x-ray diffraction analyses of asbestos in the World Trade Center dust: Asbestos content of the settled dust
On September 17 and 18, 2001, samples of settled dust and airfall debris were collected from 34 sites within a 1-km radius of the WTC collapse site, including a sample from an indoor location unaffected by rainfall, and samples of insulation from two steel beams at Ground Zero. Laboratory spectral and x-ray diffraction analyses of the field samples detected trace levels of serpentine...
Authors
Gregg A. Swayze, Roger N. Clark, Stephen J. Sutley, Todd M. Hoefen, Geoffrey S. Plumlee, Gregory P. Meeker, Isabelle Brownfield, Keith E. Livo, Laurie C. Morath
Preliminary report on using imaging spectroscopy to map ultramafic rocks, serpentinites, and tremolite-actinolite-bearing rocks in California Preliminary report on using imaging spectroscopy to map ultramafic rocks, serpentinites, and tremolite-actinolite-bearing rocks in California
Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) data were collected in approximately 3- kilometer-wide swaths over selected areas in El Dorado and Plumas Counties that contain serpentinite and ultramafic rocks as part of an experiment to determine if potentially asbestos-bearing rocks could be identified spectrally. M ineral maps created from the AVIRIS data were used...
Authors
Gregg A. Swayze, Chris T. Higgins, John P. Clinkenbeard, Raymond F. Kokaly, Roger N. Clark, Gregory P. Meeker, Stephen J. Sutley
Reflectance spectroscopy as a rapid assessment tool for the detection of amphiboles from the Libby, Montana region Reflectance spectroscopy as a rapid assessment tool for the detection of amphiboles from the Libby, Montana region
No abstract available.
Authors
Roger N. Clark, Todd M. Hoefen, Gregg A. Swayze, K. Eric Livo, Greg P. Meeker, Steve J. Sutley, Steve Wilson, Isabelle K. Brownfield, J. Sam Vance
Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems
Imaging spectroscopy is a tool that can be used to spectrally identify and spatially map materials based on their specific chemical bonds. Spectroscopic analysis requires significantly more sophistication than has been employed in conventional broadband remote sensing analysis. We describe a new system that is effective at material identification and mapping: a set of algorithms within...
Authors
Roger N. Clark, Gregg A. Swayze, K. Eric Livo, Raymond F. Kokaly, Steve J. Sutley, J. Brad Dalton, Robert R. McDougal, Carol A. Gent
USGS Digital Spectral Library splib05a USGS Digital Spectral Library splib05a
We have assembled a digital reflectance spectral library of spectra that covers wavelengths from the ultraviolet to near-infrared along with sample documentation. The library includes samples of minerals, rocks, soils, physically constructed as well as mathematically computed mixtures, vegetation, microorganisms, and man-made materials. The samples and spectra collected were assembled...
Authors
Roger N. Clark, Gregg A. Swayze, Richard K. Wise, Eric Livo, Todd M. Hoefen, Raymond F. Kokaly, Steve J. Sutley
Mapping vegetation in Yellowstone National Park using spectral feature analysis of AVIRIS data Mapping vegetation in Yellowstone National Park using spectral feature analysis of AVIRIS data
Knowledge of the distribution of vegetation on the landscape can be used to investigate ecosystem functioning. The sizes and movements of animal populations can be linked to resources provided by different plant species. This paper demonstrates the application of imaging spectroscopy to the study of vegetation in Yellowstone National Park (Yellowstone) using spectral feature analysis of...
Authors
Raymond F. Kokaly, Don G. Despain, Roger N. Clark, K. Eric Livo
Effects of spectrometer band pass, sampling, and signal‐to‐noise ratio on spectral identification using the Tetracorder algorithm Effects of spectrometer band pass, sampling, and signal‐to‐noise ratio on spectral identification using the Tetracorder algorithm
[1] Estimates of spectrometer band pass, sampling interval, and signal‐to‐noise ratio required for identification of pure minerals and plants were derived using reflectance spectra convolved to AVIRIS, HYDICE, MIVIS, VIMS, and other imaging spectrometers. For each spectral simulation, various levels of random noise were added to the reflectance spectra after convolution, and then each...
Authors
Gregg A. Swayze, Roger N. Clark, Alexander F.H. Goetz, Thomas G. Chrien, Noel S. Gorelick
Science and Products
Filter Total Items: 75
Photometric changes on Saturn's Titan: Evidence for active cryovolcanism Photometric changes on Saturn's Titan: Evidence for active cryovolcanism
We report infrared spectrophotometric variability on the surface of Saturn's moon Titan detected in images returned by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Saturn Orbiter. The changes were observed at 7°S, 138°W and occurred between October 27, 2005 and January 15, 2006. After that date the surface was unchanged until the most recent observation, March...
Authors
Robert M. Nelson, Lucas W. Kamp, Rosaly Lopes, Dennis L. Matson, Randolph L. Kirk, Bruce W. Hapke, Stephen D. Wall, Mark D. Boryta, Frank E. Leader, William D. Smythe, Karl L. Mitchell, Kevin H. Baines, Ralf Jaumann, Christophe Sotin, Roger N. Clark, Dale P. Cruikshank, Pierre Drossart, Jonathan I. Lunine, Michel Combes, Giancarlo Bellucci, Jean-Pierre Bibring, Fabrizio Capaccioni, Pricilla Cerroni, Angioletta Coradini, Vittorio Formisano, Gianrico Filacchione, Yves Langevin, Thomas B. McCord, Vito Mennella, Philip D. Nicholson, Bruno Sicardy, Patrick G.J. Irwin, John C. Pearl
Opaline silica in young deposits on Mars Opaline silica in young deposits on Mars
High spatial and spectral resolution reflectance data acquired by the Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument reveal the presence of H2O- and SiOH-bearing phases on the Martian surface. The spectra are most consistent with opaline silica and glass altered to various degrees, confirming predictions based on geochemical...
Authors
Ralph E. Milliken, Gregg A. Swayze, Raymond E. Arvidson, Janice L Bishop, Roger N. Clark, Bethany L. Ehlmann, Robert O. Green, John P. Grotzinger, R.V. Morris, Scott L. Murchie, John F. Mustard, C. Weitz
USGS Digital Spectral Library splib06a USGS Digital Spectral Library splib06a
Introduction We have assembled a digital reflectance spectral library that covers the wavelength range from the ultraviolet to far infrared along with sample documentation. The library includes samples of minerals, rocks, soils, physically constructed as well as mathematically computed mixtures, plants, vegetation communities, microorganisms, and man-made materials. The samples and...
Authors
Roger N. Clark, Gregg A. Swayze, Richard A. Wise, K. Eric Livo, Todd M. Hoefen, Raymond F. Kokaly, Stephen J. Sutley
Correlations between Cassini VIMS spectra and RADAR SAR images: Implications for Titan's surface composition and the character of the Huygens Probe Landing Site Correlations between Cassini VIMS spectra and RADAR SAR images: Implications for Titan's surface composition and the character of the Huygens Probe Landing Site
Titan's vast equatorial fields of RADAR-dark longitudinal dunes seen in Cassini RADAR synthetic aperture images correlate with one of two dark surface units discriminated as “brown” and “blue” in Visible and Infrared Mapping Spectrometer (VIMS) color composites of short-wavelength infrared spectral cubes (RGB as 2.0, 1.6, 1.3 μm). In such composites bluer materials exhibit higher...
Authors
Laurence A. Soderblom, Randolph L. Kirk, Jonathan I. Lunine, Jeffrey A. Anderson, Kevin H. Baines, Jason W. Barnes, Janet M. Barrett, Robert H. Brown, Bonnie J. Buratti, Roger N. Clark, Dale P. Cruikshank, Charles Elachi, Michael A. Janssen, Ralf Jaumann, Erich Karkoschka, Stéphane Le Mouélic, Rosaly Lopes, Ralph D. Lorenz, Thomas B. McCord, Philip D. Nicholson, Jani Radebaugh, Bashar Rizk, Christophe Sotin, Ellen R. Stofan, Tracie L. Sucharski, Martin G. Tomasko, Stephen D. Wall
Near-infrared spectral mapping of Titan's mountains and channels Near-infrared spectral mapping of Titan's mountains and channels
We investigate the spectral reflectance properties of channels and mountain ranges on Titan using data from Cassini's Visual and Infrared Mapping Spectrometer (VIMS) obtained during the T9 encounter (26 December 2005). We identify the location of channels and mountains using synthetic aperture radar maps obtained from Cassini's RADAR instrument during the T13 (30 April 2006) flyby...
Authors
Jason W. Barnes, Jani Radebaugh, Robert H. Brown, Steve Wall, Laurence A. Soderblom, Jonathan I. Lunine, Devon M. Burr, Christophe Sotin, Stephane Le Mouelic, Sebastien Rodriguez, Bonnie J. Buratti, Roger N. Clark, Kevin H. Baines, Ralf Jaumann, Philip D. Nicholson, Randolph L. Kirk, Rosaly Lopes, Ralph D. Lorenz, Ken Mitchell, Charles A. Wood
Spectroscopic and x-ray diffraction analyses of asbestos in the World Trade Center dust: Asbestos content of the settled dust Spectroscopic and x-ray diffraction analyses of asbestos in the World Trade Center dust: Asbestos content of the settled dust
On September 17 and 18, 2001, samples of settled dust and airfall debris were collected from 34 sites within a 1-km radius of the WTC collapse site, including a sample from an indoor location unaffected by rainfall, and samples of insulation from two steel beams at Ground Zero. Laboratory spectral and x-ray diffraction analyses of the field samples detected trace levels of serpentine...
Authors
Gregg A. Swayze, Roger N. Clark, Stephen J. Sutley, Todd M. Hoefen, Geoffrey S. Plumlee, Gregory P. Meeker, Isabelle Brownfield, Keith E. Livo, Laurie C. Morath
Preliminary report on using imaging spectroscopy to map ultramafic rocks, serpentinites, and tremolite-actinolite-bearing rocks in California Preliminary report on using imaging spectroscopy to map ultramafic rocks, serpentinites, and tremolite-actinolite-bearing rocks in California
Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) data were collected in approximately 3- kilometer-wide swaths over selected areas in El Dorado and Plumas Counties that contain serpentinite and ultramafic rocks as part of an experiment to determine if potentially asbestos-bearing rocks could be identified spectrally. M ineral maps created from the AVIRIS data were used...
Authors
Gregg A. Swayze, Chris T. Higgins, John P. Clinkenbeard, Raymond F. Kokaly, Roger N. Clark, Gregory P. Meeker, Stephen J. Sutley
Reflectance spectroscopy as a rapid assessment tool for the detection of amphiboles from the Libby, Montana region Reflectance spectroscopy as a rapid assessment tool for the detection of amphiboles from the Libby, Montana region
No abstract available.
Authors
Roger N. Clark, Todd M. Hoefen, Gregg A. Swayze, K. Eric Livo, Greg P. Meeker, Steve J. Sutley, Steve Wilson, Isabelle K. Brownfield, J. Sam Vance
Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems
Imaging spectroscopy is a tool that can be used to spectrally identify and spatially map materials based on their specific chemical bonds. Spectroscopic analysis requires significantly more sophistication than has been employed in conventional broadband remote sensing analysis. We describe a new system that is effective at material identification and mapping: a set of algorithms within...
Authors
Roger N. Clark, Gregg A. Swayze, K. Eric Livo, Raymond F. Kokaly, Steve J. Sutley, J. Brad Dalton, Robert R. McDougal, Carol A. Gent
USGS Digital Spectral Library splib05a USGS Digital Spectral Library splib05a
We have assembled a digital reflectance spectral library of spectra that covers wavelengths from the ultraviolet to near-infrared along with sample documentation. The library includes samples of minerals, rocks, soils, physically constructed as well as mathematically computed mixtures, vegetation, microorganisms, and man-made materials. The samples and spectra collected were assembled...
Authors
Roger N. Clark, Gregg A. Swayze, Richard K. Wise, Eric Livo, Todd M. Hoefen, Raymond F. Kokaly, Steve J. Sutley
Mapping vegetation in Yellowstone National Park using spectral feature analysis of AVIRIS data Mapping vegetation in Yellowstone National Park using spectral feature analysis of AVIRIS data
Knowledge of the distribution of vegetation on the landscape can be used to investigate ecosystem functioning. The sizes and movements of animal populations can be linked to resources provided by different plant species. This paper demonstrates the application of imaging spectroscopy to the study of vegetation in Yellowstone National Park (Yellowstone) using spectral feature analysis of...
Authors
Raymond F. Kokaly, Don G. Despain, Roger N. Clark, K. Eric Livo
Effects of spectrometer band pass, sampling, and signal‐to‐noise ratio on spectral identification using the Tetracorder algorithm Effects of spectrometer band pass, sampling, and signal‐to‐noise ratio on spectral identification using the Tetracorder algorithm
[1] Estimates of spectrometer band pass, sampling interval, and signal‐to‐noise ratio required for identification of pure minerals and plants were derived using reflectance spectra convolved to AVIRIS, HYDICE, MIVIS, VIMS, and other imaging spectrometers. For each spectral simulation, various levels of random noise were added to the reflectance spectra after convolution, and then each...
Authors
Gregg A. Swayze, Roger N. Clark, Alexander F.H. Goetz, Thomas G. Chrien, Noel S. Gorelick