Giovannina Mansir 182 presentation
13
Correction for the Martian Atmosphere in CRISM Spectra Giovannina Mansir University of California, Santa Cruz 12/03/2014
-
Upload
giovannina-mansir -
Category
Documents
-
view
52 -
download
3
Transcript of Giovannina Mansir 182 presentation
Correction for the Martian
Atmosphere in CRISM Spectra
Giovannina Mansir University of California, Santa Cruz
12/03/2014
ANCIENT MARS
12/03/2014
o Once had abundant surface
water (4.1 – 3.7 billion years
ago)
o Formed clay minerals such as
kaolinite, nontronite, and
montmorillonite
o Current mineralogy suggests
soil has between 1.5% - 3%
water by mass
Possible surface of ancient Mars
Rendered by Celestia
MRO
12/03/2014
o Mars Reconnaissance Orbiter
o Launched in 2006
o Main objective is to
o Monitor weather
o Study surface
o Find possible rover
landing sites
Concept art of MRO in orbit
Image credit: NASA/JPL
CRISM
12/03/2014
o Compact Reconnaissance Imaging Spectrometer for Mars
o Looks at the chemical composition of surface
o Used in proposed landing site evaluations for Icebreaker Life (2020)
o Monitoring dust and ice aerosols
Surface Map of Mars by CRISM
CRISM IMAGES
12/03/2014
o 2 spacial dimensions (640 x 480 pixels)
o 1 wavelength dimension (438 bands per pixel)
o False colors used to highlight clays using spectral absorptions
Mawrth Vallis (CRISM Image)
Single Pixel Spectral Profile
THE PROBLEM
12/03/2014
THE PROBLEM
12/03/2014
PREVIOUS SOLUTION
12/03/2014
Martian Volcanoes (CRISM Image Database)
o Estimate the atmospheric transmission by volcano scans
o (Abundance at base) / (Abundance at summit) = Scaling relation
21,000 m
200,000 m
THE BETTER WAY (EPF AND DISORT)
12/03/2014
o Emission Phase Angles
o Used to create an opacity
spectrum and remove CO2
triplet
o Can’t be used for aerosols
because they aren’t evenly
mixed
o Discrete Ordinate-method Radiative Transfer
o FORTRAN program that models multi-layer, plane-parallel atmospheres
o Model how dust and ice aerosols adjust the spectra
From the 2009 CRISM Workshop Presentation
DISORT MODELS 12/03/2014
o Between pixels, the following parameters change:
o Surface albedo (percentage of light it can reflect)
o Dust optical depth
o Ice optical depth
o Incident, emission, and phase angles
o Everything except for the albedo can be determined for an individual CRISM
pixel
o Database of 12,500
DISORT models total
ATMOSPHERIC CORRECTIONS 12/03/2014
o Program takes
o Observed radiance value
o Aerosol optical depths
o Angle information
o Wavelength value
o Creates an extrapolated DISORT
model
o Returns the surface albedo
spectrum
ERROR ANALYSIS (IN PROGRESS) 12/03/2014
o Use generic martian dust spectrum
o Mix with minerals of interest
o Model atmosphere (with noise)
o Create false CRISM image with various
emission phase angles (EPF)
o Run through atmospheric corrections and
compare with original surface spectra
Arabia Terra (CRISM Image)
o Curiosity will also be able to verify the work from its location in Gale
Crater in a few months
ACKNOWLEDGMENTS
12/03/2014
o Eldar Noe Dobrea (NASA Ames/Planetary Science Institute)
o Mike Wolff (Space Science Institute)
o Courtney Dressing (Harvard University)
o Szilárd Gyalay (UC Los Angeles)
o Jonathan Fortney (UC Santa Cruz)
![WAC 182 - 12 CHAPTER - lawfilesext.leg.wa.govlawfilesext.leg.wa.gov/law/WACArchive/2014/WAC 182 - 12 CHAPTE… · (10/28/13) [Ch. 182-12 WAC p. 1] Chapter 182-12 Chapter 182-12 WAC](https://static.fdocuments.net/doc/165x107/5f937086d75d77697316c603/wac-182-12-chapter-182-12-chapte-102813-ch-182-12-wac-p-1-chapter.jpg)
