THERMAL INERTIA CHARACTERIZATION OF VASTITAS BOREALIS AND OLYMPIA UNDAE

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THERMAL INERTIA CHARACTERIZATION OF VASTITAS
BOREALIS ANDOLYMPIA UNDAE

• Timothy N. Titus
• United States Geological Survey, Flagstaff,
  Arizona 86001

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Motivation Background

• GRS Suite of Instruments
• High Concentrations of WEH measurements in polar
  regions.
• WEH minimum in Eastern Olympia Undae.
• TES KRC
• Successfully used KRC Thermal Model combined with
  TES observations to detect water ice at edge of
  the SPRC

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The Thermal Model

• TES Albedo Thermal Bolometer Observations
• Restricted to Late-Spring Summer
• KRC Two-Layer Model
• Surface Layer Thermal Inertia
• Surface Layer Depth
• Bottom Layer Thermal Inertia
• Model Fits
• Time-dependent Albedo
• Constant Dust Opacity of 0.2

Depth
Thermal Inertia
Thermal Inertia
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Top Layer Thermal Inertia
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Lower Layer Thermal Inertia
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Top Layer Depth (mm)
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Cross-SectionLatitude 80.5N

• 5-10 cm of sand on top of ice

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Cross-SectionLatitude 80.5N

• 5-10 cm of sand on top of ice

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Cross-SectionLongitude 179 E

• Ice Table Edge is 66N

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Cross-SectionLongitude 179 E

• Ice Table Edge is 66N

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Cross-SectionLongitude 189 E

• Ice Table Edge is 67N

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Cross-SectionLongitude 189 E

• Ice Table Edge is 67N

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Cross-SectionLongitude 221 E

• Ice Table Edge is south of 65N

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Cross-SectionLongitude 221 E

• Ice Table Edge is south of 65N

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Results

• Olympia Undae is frozen with 5-10 cm overburden
  of sand. (Consistent with papers by Mary Bourke
  and Bill Feldman et al.)
• The thermal edge of the ice table is consistent
  with that derived from neutrons.
• Low hydrogen detection in Olympia Undae
  corresponds to a deeper ice table.
• The ice table may have a thermal inertia higher
  than that expected for either bedrock or pure
  ice.
• Could be an effect from non-atmospherically
  corrected albedo
• Possible Implications for formation mechanisms

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Future Work

• New MDAP Funding
• 60km resolution
• Both Polar Regions
• Variable Opacity
• Atmospherically-corrected albedo
• Combine with Mars Odyssey Neutron Spectrometer
  observations