Colin HoASU Mars Space Flight Facility
Mentor: Phil Christensen
Full atmospheric correction of Thermal Emission Imaging System IR stamps would provide a valuable source of spectral data that can be used for determining the Martian surface composition at a high resolution (100m/pixel) THEMIS visible stamp and TES
mineral map resolution comparisonimage from JMARS
To determine if atmospherically correcting Thermal Emission Imaging System (THEMIS) IR spectra using Thermal Emission Spectrometer (TES) data as a basis provides useful data
Assumptions◦ TES data is pure surface emissivity◦ General atmospheric composition has little shift
over time
Selecting an area Acquiring data
Data access tools TES – vanilla THEMIS -
THMPROC
Processing data
Programming tool davinci Using scripts
such as i2i (Christensen)
TES pixel outlined upon THEMIS stamp with MOLA in background
Image from JMARS
Area of 44 to 44.25E, 2.75 to 3N used (day IR)
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1.4THEMIS vs TES emissivity
wavenumber cm-1
emis
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average THEMIS emissivity
TES emissivity
0200400600800100012001400160018000
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1.4THEMIS vs TES emissivity
wavenumber cm-1
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average THEMIS emissivity
TES emissivity
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1.1THEMIS vs i2i converted TES emissivity
wavenumber cm-1
emis
sivi
ty
average THEMIS emissivity
i2i converted TES emissivity
6007008009001000110012001300140015000.1
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1.1THEMIS vs i2i converted TES emissivity
wavenumber cm-1
emis
sivi
ty
average THEMIS emissivity
i2i converted TES emissivity
Raw data comparison After processing using i2i
The derived atmospheric emissivity correlated to the expected atmospheric spectral dust emissivity
Atmospheric dust emissivity (Smith, Bandfield, Christensen, 2000)
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0.25derived atmospheric emissivity
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Atmospheric emissivity derived from the difference between TES and THEMIS
In the initial test case, the results were found to be suitable for atmospheric correction purposes
Plans for future improvement◦ Using a larger temporal and spatial spread of data◦ Applying multiple methods of determining
emissivity difference◦ Automating data retrieval, and processing
MentorPhilip Christensen
Special ThanksKim Murray
Smith, Bandfield, Christensen (2000), Separation of atmospheric and surface spectral features in Mars Global Surveyor Thermal Emission Spectrometer (TES) spectra, Journal of Geophysical Research. Vol 105. No E4. Pages 9589-9607
Bandfield (2002), Global mineral distributions on Mars, Journal of Geophysical Research, 10.1029/2001JE001510.
Mars Global Data, http://jmars.asu.edu/data/ THMPROC, http://thmproc.mars.asu.edu/ davinci – Main Page. 6-25-07,
“http://davinci.asu.edu/index.php/Main_Page” Arizona Space Grant Consortium logos. 8-28-08,
http://spacegrant.arizona.edu/about/azsgc_logos