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Thermal Emission Imaging System Atmospheric Correction. Colin Ho ASU Mars Space Flight Facility Mentor: Phil Christensen. Overview.
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Thermal Emission Imaging System Atmospheric Correction Colin Ho ASU Mars Space Flight Facility Mentor: Phil Christensen
Overview • 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 comparison image from JMARS
Objective • 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
Method 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
Test Case • Area of 44 to 44.25E, 2.75 to 3N used (day IR) Raw data comparison After processing using i2i
Test Case Results • The derived atmospheric emissivity correlated to the expected atmospheric spectral dust emissivity Atmospheric dust emissivity (Smith, Bandfield, Christensen, 2000) Atmospheric emissivity derived from the difference between TES and THEMIS
Analysis • 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
Acknowledgments Mentor Philip Christensen Special Thanks Kim Murray
Sources • 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