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

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TES emissivity

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1.4THEMIS vs TES emissivity

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average THEMIS emissivity

TES emissivity

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1.1THEMIS vs i2i converted TES emissivity

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i2i converted TES emissivity

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1.1THEMIS vs i2i converted TES emissivity

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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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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