Roger N Clark (Former Employee)
Science and Products
Filter Total Items: 85
Inorganic chemical composition and chemical reactivity of settled dust generated by the World Trade Center building collapse Inorganic chemical composition and chemical reactivity of settled dust generated by the World Trade Center building collapse
Samples of dust deposited around lower Manhattan by the September 11, 2001, World Trade Center (WTC) collapse have inorganic chemical compositions that result in part from the variable chemical contributions of concrete, gypsum wallboard, glass fibers, window glass, and other materials contained in the buildings. The dust deposits were also modified chemically by variable interactions...
Authors
Geoffrey S. Plumlee, Philip L. Hageman, Paul J. Lamothe, Thomas L. Ziegler, Gregory P. Meeker, Peter M. Theodorakos, Isabelle Brownfield, Monique G. Adams, Gregg A. Swayze, Todd M. Hoefen, Joseph E. Taggart, Roger N. Clark, S. Wilson, Stephen J. Sutley
Global circulation as the main source of cloud activity on Titan Global circulation as the main source of cloud activity on Titan
Clouds on Titan result from the condensation of methane and ethane and, as on other planets, are primarily structured by circulation of the atmosphere. At present, cloud activity mainly occurs in the southern (summer) hemisphere, arising near the pole and at mid-latitudes from cumulus updrafts triggered by surface heating and/or local methane sources, and at the north (winter) pole...
Authors
S. Rodriguez, Stéphane Le Mouélic, P. Rannou, G. Tobie, K. H. Baines, J. W. Barnes, C.A. Griffith, M. Hirtzig, K.M. Pitman, Christophe Sotin, R. H. Brown, B. J. Buratti, R. N. Clark, P. D. Nicholson
VIMS spectral mapping observations of Titan during the Cassini prime mission VIMS spectral mapping observations of Titan during the Cassini prime mission
This is a data paper designed to facilitate the use of and comparisons to Cassini/visual and infrared mapping spectrometer (VIMS) spectral mapping data of Saturn's moon Titan. We present thumbnail orthographic projections of flyby mosaics from each Titan encounter during the Cassini prime mission, 2004 July 1 through 2008 June 30. For each flyby we also describe the encounter geometry...
Authors
J. W. Barnes, J.M. Soderblom, R. H. Brown, B. J. Buratti, Christophe Sotin, K. H. Baines, R. N. Clark, R. Jaumann, T. B. McCord, R. Nelson, Stéphane Le Mouélic, S. Rodriguez, C. Griffith, P. Penteado, F. Tosi, K.M. Pitman, L. Soderblom, K. Stephan, P. Hayne, G. Vixie, J.-P. Bibring, G. Bellucci, F. Capaccioni, P. Cerroni, A. Coradini, D. P. Cruikshank, P. Drossart, V. Formisano, Y. Langevin, D. L. Matson, P. D. Nicholson, B. Sicardy
Shoreline features of Titan's Ontario Lacus from Cassini/VIMS observations Shoreline features of Titan's Ontario Lacus from Cassini/VIMS observations
We analyze observations of Titan's south polar lake Ontario Lacus obtained by Cassini's Visual and Infrared Mapping Spectrometer during the 38th flyby of Titan (T38; 2007 December 5). These near-closest-approach observations have the highest signal-to-noise, the finest spatial resolution, and the least atmospheric influence of any near-infrared lake observation to date. We use the large...
Authors
J. W. Barnes, R. H. Brown, J.M. Soderblom, L.A. Soderblom, R. Jaumann, B. Jackson, Stéphane Le Mouélic, Christophe Sotin, B. J. Buratti, K.M. Pitman, K. H. Baines, R. N. Clark, P. D. Nicholson, E. P. Turtle, J. Perry
Characterization of clouds in Titan's tropical atmosphere Characterization of clouds in Titan's tropical atmosphere
Images of Titan's clouds, possible over the past 10 years, indicate primarily discrete convective methane clouds near the south and north poles and an immense stratiform cloud, likely composed of ethane, around the north pole. Here we present spectral images from Cassini's Visual Mapping Infrared Spectrometer that reveal the increasing presence of clouds in Titan's tropical atmosphere...
Authors
C.A. Griffith, P. Penteado, S. Rodriguez, Stéphane Le Mouélic, K. H. Baines, B. Buratti, R. Clark, P. Nicholson, R. Jaumann, Christophe Sotin
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
Mapping and interpretation of Sinlap crater on Titan using Cassini VIMS and RADAR data Mapping and interpretation of Sinlap crater on Titan using Cassini VIMS and RADAR data
Only a few impact craters have been unambiguously detected on Titan by the Cassini-Huygens mission. Among these, Sinlap is the only one that has been observed both by the RADAR and VIMS instruments. This paper describes observations at centimeter and infrared wavelengths which provide complementary information about the composition, topography, and surface roughness. Several units appear...
Authors
Stéphane Le Mouélic, P. Paillou, M.A. Janssen, J. W. Barnes, S. Rodriguez, Christophe Sotin, R. H. Brown, K. H. Baines, B. J. Buratti, R. N. Clark, M. Crapeau, P.J. Encrenaz, R. Jaumann, D. Geudtner, F. Paganelli, L. Soderblom, G. Tobie, S. Wall
Fluvial erosion and post-erosional processes on Titan Fluvial erosion and post-erosional processes on Titan
The surface of Titan has been revealed by Cassini observations in the infrared and radar wavelength ranges as well as locally by the Huygens lander instruments. Sand seas, recently discovered lakes, distinct landscapes and dendritic erosion patterns indicate dynamic surface processes. This study focus on erosional and depositional features that can be used to constrain the amount of...
Authors
R. Jaumann, R. H. Brown, K. Stephan, J. W. Barnes, L.A. Soderblom, Christophe Sotin, Stéphane Le Mouélic, R. N. Clark, J. Soderblom, B. J. Buratti, R. Wagner, T. B. McCord, S. Rodriguez, K. H. Baines, D. P. Cruikshank, P. D. Nicholson, C.A. Griffith, M. Langhans, R. D. Lorenz
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
Global-scale surface spectral variations on Titan seen from Cassini/VIMS Global-scale surface spectral variations on Titan seen from Cassini/VIMS
We present global-scale maps of Titan from the Visual and Infrared Mapping Spectrometer (VIMS) instrument on Cassini. We map at 64 near-infrared wavelengths simultaneously, covering the atmospheric windows at 0.94, 1.08, 1.28, 1.6, 2.0, 2.8, and 5 ??m with a typical resolution of 50 km/pixel or a typical total integration time of 1 s. Our maps have five to ten times the resolution of...
Authors
J. W. Barnes, R. H. Brown, L. Soderblom, B. J. Buratti, Christophe Sotin, S. Rodriguez, Stéphane Le Mouélic, K. H. Baines, R. Clark, P. Nicholson
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
Science and Products
Filter Total Items: 85
Inorganic chemical composition and chemical reactivity of settled dust generated by the World Trade Center building collapse Inorganic chemical composition and chemical reactivity of settled dust generated by the World Trade Center building collapse
Samples of dust deposited around lower Manhattan by the September 11, 2001, World Trade Center (WTC) collapse have inorganic chemical compositions that result in part from the variable chemical contributions of concrete, gypsum wallboard, glass fibers, window glass, and other materials contained in the buildings. The dust deposits were also modified chemically by variable interactions...
Authors
Geoffrey S. Plumlee, Philip L. Hageman, Paul J. Lamothe, Thomas L. Ziegler, Gregory P. Meeker, Peter M. Theodorakos, Isabelle Brownfield, Monique G. Adams, Gregg A. Swayze, Todd M. Hoefen, Joseph E. Taggart, Roger N. Clark, S. Wilson, Stephen J. Sutley
Global circulation as the main source of cloud activity on Titan Global circulation as the main source of cloud activity on Titan
Clouds on Titan result from the condensation of methane and ethane and, as on other planets, are primarily structured by circulation of the atmosphere. At present, cloud activity mainly occurs in the southern (summer) hemisphere, arising near the pole and at mid-latitudes from cumulus updrafts triggered by surface heating and/or local methane sources, and at the north (winter) pole...
Authors
S. Rodriguez, Stéphane Le Mouélic, P. Rannou, G. Tobie, K. H. Baines, J. W. Barnes, C.A. Griffith, M. Hirtzig, K.M. Pitman, Christophe Sotin, R. H. Brown, B. J. Buratti, R. N. Clark, P. D. Nicholson
VIMS spectral mapping observations of Titan during the Cassini prime mission VIMS spectral mapping observations of Titan during the Cassini prime mission
This is a data paper designed to facilitate the use of and comparisons to Cassini/visual and infrared mapping spectrometer (VIMS) spectral mapping data of Saturn's moon Titan. We present thumbnail orthographic projections of flyby mosaics from each Titan encounter during the Cassini prime mission, 2004 July 1 through 2008 June 30. For each flyby we also describe the encounter geometry...
Authors
J. W. Barnes, J.M. Soderblom, R. H. Brown, B. J. Buratti, Christophe Sotin, K. H. Baines, R. N. Clark, R. Jaumann, T. B. McCord, R. Nelson, Stéphane Le Mouélic, S. Rodriguez, C. Griffith, P. Penteado, F. Tosi, K.M. Pitman, L. Soderblom, K. Stephan, P. Hayne, G. Vixie, J.-P. Bibring, G. Bellucci, F. Capaccioni, P. Cerroni, A. Coradini, D. P. Cruikshank, P. Drossart, V. Formisano, Y. Langevin, D. L. Matson, P. D. Nicholson, B. Sicardy
Shoreline features of Titan's Ontario Lacus from Cassini/VIMS observations Shoreline features of Titan's Ontario Lacus from Cassini/VIMS observations
We analyze observations of Titan's south polar lake Ontario Lacus obtained by Cassini's Visual and Infrared Mapping Spectrometer during the 38th flyby of Titan (T38; 2007 December 5). These near-closest-approach observations have the highest signal-to-noise, the finest spatial resolution, and the least atmospheric influence of any near-infrared lake observation to date. We use the large...
Authors
J. W. Barnes, R. H. Brown, J.M. Soderblom, L.A. Soderblom, R. Jaumann, B. Jackson, Stéphane Le Mouélic, Christophe Sotin, B. J. Buratti, K.M. Pitman, K. H. Baines, R. N. Clark, P. D. Nicholson, E. P. Turtle, J. Perry
Characterization of clouds in Titan's tropical atmosphere Characterization of clouds in Titan's tropical atmosphere
Images of Titan's clouds, possible over the past 10 years, indicate primarily discrete convective methane clouds near the south and north poles and an immense stratiform cloud, likely composed of ethane, around the north pole. Here we present spectral images from Cassini's Visual Mapping Infrared Spectrometer that reveal the increasing presence of clouds in Titan's tropical atmosphere...
Authors
C.A. Griffith, P. Penteado, S. Rodriguez, Stéphane Le Mouélic, K. H. Baines, B. Buratti, R. Clark, P. Nicholson, R. Jaumann, Christophe Sotin
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
Mapping and interpretation of Sinlap crater on Titan using Cassini VIMS and RADAR data Mapping and interpretation of Sinlap crater on Titan using Cassini VIMS and RADAR data
Only a few impact craters have been unambiguously detected on Titan by the Cassini-Huygens mission. Among these, Sinlap is the only one that has been observed both by the RADAR and VIMS instruments. This paper describes observations at centimeter and infrared wavelengths which provide complementary information about the composition, topography, and surface roughness. Several units appear...
Authors
Stéphane Le Mouélic, P. Paillou, M.A. Janssen, J. W. Barnes, S. Rodriguez, Christophe Sotin, R. H. Brown, K. H. Baines, B. J. Buratti, R. N. Clark, M. Crapeau, P.J. Encrenaz, R. Jaumann, D. Geudtner, F. Paganelli, L. Soderblom, G. Tobie, S. Wall
Fluvial erosion and post-erosional processes on Titan Fluvial erosion and post-erosional processes on Titan
The surface of Titan has been revealed by Cassini observations in the infrared and radar wavelength ranges as well as locally by the Huygens lander instruments. Sand seas, recently discovered lakes, distinct landscapes and dendritic erosion patterns indicate dynamic surface processes. This study focus on erosional and depositional features that can be used to constrain the amount of...
Authors
R. Jaumann, R. H. Brown, K. Stephan, J. W. Barnes, L.A. Soderblom, Christophe Sotin, Stéphane Le Mouélic, R. N. Clark, J. Soderblom, B. J. Buratti, R. Wagner, T. B. McCord, S. Rodriguez, K. H. Baines, D. P. Cruikshank, P. D. Nicholson, C.A. Griffith, M. Langhans, R. D. Lorenz
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
Global-scale surface spectral variations on Titan seen from Cassini/VIMS Global-scale surface spectral variations on Titan seen from Cassini/VIMS
We present global-scale maps of Titan from the Visual and Infrared Mapping Spectrometer (VIMS) instrument on Cassini. We map at 64 near-infrared wavelengths simultaneously, covering the atmospheric windows at 0.94, 1.08, 1.28, 1.6, 2.0, 2.8, and 5 ??m with a typical resolution of 50 km/pixel or a typical total integration time of 1 s. Our maps have five to ten times the resolution of...
Authors
J. W. Barnes, R. H. Brown, L. Soderblom, B. J. Buratti, Christophe Sotin, S. Rodriguez, Stéphane Le Mouélic, K. H. Baines, R. Clark, P. Nicholson
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