Near-Infrared Imaging of Mars from HST

Surface Reflectance, Photometric Properties, and Implications for MOLA Data

James Bell, Michael J. Wolff, Thomas C. Daley, David Crisp, Philip B. James, Steven W. Lee, John T. Trauger, Robin W. Evans

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

We report initial results from Hubble Space Telescope (HST) images of Mars obtained at a near-IR wavelength of 1042 nm between February 1995 and June 1997. The images provide the highest spatial resolution global near-IR measurements of Mars obtained to date. The data have been calibrated to radiance factor (I/F) to an absolute accuracy of 2 to 5% (including new refinements to several HST calibration parameters) and now exist as a set of coregistered, map-projected images spanning a range of phase angles between 10° and 41°. The relatively high spatial resolution (20-30 km/pixel) global maps, when compared with Viking-era global albedo maps, reveal that substantial variations in Mars surface albedo patterns have occurred in the past 20 years. The most obvious changes include several classical dark regions that have become substantially brighter, and a few formerly bright regions that have darkened. The normal albedo of typical surface regions in the near-IR is derived from the multiple phase angle observations and is found to be bimodal with typical bright and dark values of 0.36 and 0.18, respectively. The surface near-IR phase coefficient ranges from 0.0 to 0.013 mag/deg, and there is no systematic correlation between phase coefficient and normal albedo. This observation is consistent with the diffusely scattering nature of the martian atmosphere even during times of low dust opacity. The data presented here may facilitate the planning and optimization of measurements to be obtained by the Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA), which will begin mapping the planet in 1999. These HST data also provide a basis for comparison with future MOLA and Mars Orbiter Camera (MOC) data in searches for seasonal and interannual variations in surface and polar cap albedo.

Original languageEnglish (US)
Pages (from-to)25-35
Number of pages11
JournalIcarus
Volume138
Issue number1
DOIs
StatePublished - Mar 1 1999
Externally publishedYes

Fingerprint

Mars Global Surveyor
surface reflectance
albedo
altimeter
Hubble Space Telescope
mars
Mars
near infrared
laser
reflectance
annual variations
phase shift
spatial resolution
Mars surface
polar caps
high resolution
coefficients
opacity
radiance
caps

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Near-Infrared Imaging of Mars from HST : Surface Reflectance, Photometric Properties, and Implications for MOLA Data. / Bell, James; Wolff, Michael J.; Daley, Thomas C.; Crisp, David; James, Philip B.; Lee, Steven W.; Trauger, John T.; Evans, Robin W.

In: Icarus, Vol. 138, No. 1, 01.03.1999, p. 25-35.

Research output: Contribution to journalArticle

Bell, J, Wolff, MJ, Daley, TC, Crisp, D, James, PB, Lee, SW, Trauger, JT & Evans, RW 1999, 'Near-Infrared Imaging of Mars from HST: Surface Reflectance, Photometric Properties, and Implications for MOLA Data', Icarus, vol. 138, no. 1, pp. 25-35. https://doi.org/10.1006/icar.1998.6057
Bell, James ; Wolff, Michael J. ; Daley, Thomas C. ; Crisp, David ; James, Philip B. ; Lee, Steven W. ; Trauger, John T. ; Evans, Robin W. / Near-Infrared Imaging of Mars from HST : Surface Reflectance, Photometric Properties, and Implications for MOLA Data. In: Icarus. 1999 ; Vol. 138, No. 1. pp. 25-35.
@article{298ff7de9c4a475aacb5ce4236ae9cd0,
title = "Near-Infrared Imaging of Mars from HST: Surface Reflectance, Photometric Properties, and Implications for MOLA Data",
abstract = "We report initial results from Hubble Space Telescope (HST) images of Mars obtained at a near-IR wavelength of 1042 nm between February 1995 and June 1997. The images provide the highest spatial resolution global near-IR measurements of Mars obtained to date. The data have been calibrated to radiance factor (I/F) to an absolute accuracy of 2 to 5{\%} (including new refinements to several HST calibration parameters) and now exist as a set of coregistered, map-projected images spanning a range of phase angles between 10° and 41°. The relatively high spatial resolution (20-30 km/pixel) global maps, when compared with Viking-era global albedo maps, reveal that substantial variations in Mars surface albedo patterns have occurred in the past 20 years. The most obvious changes include several classical dark regions that have become substantially brighter, and a few formerly bright regions that have darkened. The normal albedo of typical surface regions in the near-IR is derived from the multiple phase angle observations and is found to be bimodal with typical bright and dark values of 0.36 and 0.18, respectively. The surface near-IR phase coefficient ranges from 0.0 to 0.013 mag/deg, and there is no systematic correlation between phase coefficient and normal albedo. This observation is consistent with the diffusely scattering nature of the martian atmosphere even during times of low dust opacity. The data presented here may facilitate the planning and optimization of measurements to be obtained by the Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA), which will begin mapping the planet in 1999. These HST data also provide a basis for comparison with future MOLA and Mars Orbiter Camera (MOC) data in searches for seasonal and interannual variations in surface and polar cap albedo.",
author = "James Bell and Wolff, {Michael J.} and Daley, {Thomas C.} and David Crisp and James, {Philip B.} and Lee, {Steven W.} and Trauger, {John T.} and Evans, {Robin W.}",
year = "1999",
month = "3",
day = "1",
doi = "10.1006/icar.1998.6057",
language = "English (US)",
volume = "138",
pages = "25--35",
journal = "Icarus",
issn = "0019-1035",
publisher = "Academic Press Inc.",
number = "1",

}

TY - JOUR

T1 - Near-Infrared Imaging of Mars from HST

T2 - Surface Reflectance, Photometric Properties, and Implications for MOLA Data

AU - Bell, James

AU - Wolff, Michael J.

AU - Daley, Thomas C.

AU - Crisp, David

AU - James, Philip B.

AU - Lee, Steven W.

AU - Trauger, John T.

AU - Evans, Robin W.

PY - 1999/3/1

Y1 - 1999/3/1

N2 - We report initial results from Hubble Space Telescope (HST) images of Mars obtained at a near-IR wavelength of 1042 nm between February 1995 and June 1997. The images provide the highest spatial resolution global near-IR measurements of Mars obtained to date. The data have been calibrated to radiance factor (I/F) to an absolute accuracy of 2 to 5% (including new refinements to several HST calibration parameters) and now exist as a set of coregistered, map-projected images spanning a range of phase angles between 10° and 41°. The relatively high spatial resolution (20-30 km/pixel) global maps, when compared with Viking-era global albedo maps, reveal that substantial variations in Mars surface albedo patterns have occurred in the past 20 years. The most obvious changes include several classical dark regions that have become substantially brighter, and a few formerly bright regions that have darkened. The normal albedo of typical surface regions in the near-IR is derived from the multiple phase angle observations and is found to be bimodal with typical bright and dark values of 0.36 and 0.18, respectively. The surface near-IR phase coefficient ranges from 0.0 to 0.013 mag/deg, and there is no systematic correlation between phase coefficient and normal albedo. This observation is consistent with the diffusely scattering nature of the martian atmosphere even during times of low dust opacity. The data presented here may facilitate the planning and optimization of measurements to be obtained by the Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA), which will begin mapping the planet in 1999. These HST data also provide a basis for comparison with future MOLA and Mars Orbiter Camera (MOC) data in searches for seasonal and interannual variations in surface and polar cap albedo.

AB - We report initial results from Hubble Space Telescope (HST) images of Mars obtained at a near-IR wavelength of 1042 nm between February 1995 and June 1997. The images provide the highest spatial resolution global near-IR measurements of Mars obtained to date. The data have been calibrated to radiance factor (I/F) to an absolute accuracy of 2 to 5% (including new refinements to several HST calibration parameters) and now exist as a set of coregistered, map-projected images spanning a range of phase angles between 10° and 41°. The relatively high spatial resolution (20-30 km/pixel) global maps, when compared with Viking-era global albedo maps, reveal that substantial variations in Mars surface albedo patterns have occurred in the past 20 years. The most obvious changes include several classical dark regions that have become substantially brighter, and a few formerly bright regions that have darkened. The normal albedo of typical surface regions in the near-IR is derived from the multiple phase angle observations and is found to be bimodal with typical bright and dark values of 0.36 and 0.18, respectively. The surface near-IR phase coefficient ranges from 0.0 to 0.013 mag/deg, and there is no systematic correlation between phase coefficient and normal albedo. This observation is consistent with the diffusely scattering nature of the martian atmosphere even during times of low dust opacity. The data presented here may facilitate the planning and optimization of measurements to be obtained by the Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA), which will begin mapping the planet in 1999. These HST data also provide a basis for comparison with future MOLA and Mars Orbiter Camera (MOC) data in searches for seasonal and interannual variations in surface and polar cap albedo.

UR - http://www.scopus.com/inward/record.url?scp=0002470099&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0002470099&partnerID=8YFLogxK

U2 - 10.1006/icar.1998.6057

DO - 10.1006/icar.1998.6057

M3 - Article

VL - 138

SP - 25

EP - 35

JO - Icarus

JF - Icarus

SN - 0019-1035

IS - 1

ER -