Transcript Polarization Surface-State Retrieval in the Presence of

Polarization Surface-State
Retrieval in the Presence of
Atmospheric Perturbations
Mentor: Dr. Carol Bruegge (JPL)
By: Victor Chu
Who
• Funding: Non-NASA contract
– ICATS project (Image Chain Analysis Technology for
Space)
• Orbiting Carbon Observatory (OCO)
– OCO requires knowledge of surface polarization
properties for its retrieval algorithm
– The task utilizes a retrieval code also used by OCO
• Multiangle SpectroPolarimetric Imager (MSPI)
– JPL polarimeter built to study aerosols
Pre-Cursor
• Multi-angle Imaging SpectroRadiometer
(MISR)
• Orbit since 1999
• 275m resolution
• 0º, 26º, 46º, 60º, and 70º fore and aft of
nadir
• Spectral Bands - 446, 558, 672, 866 nm
• Multi-angle – Unique Capabilities
What it can do
MISR generated image
Enhanced sensitivity to
aerosols
Polarization
• MISR lacks Polarization Sensor
• Polarization Adds New Dimension
• New level of clarity
What it COULD do
• Camouflaged objects
are difficult to detect
with MISR
• Polarization
objects
extremely
regardless
makes
appear
clear
Do you see any trucks?
What about now?
See them now?
MSPI
• Follow-on instrument to MISR
• Many factors affect polarimetric accuracy
• Requires calibration
Radiative Programs
• VLIDORT
• Few Polarization calculators
– MODTRAN
• Developed by the Air Force Geophysical Laboratory
(AFGL)
– MODTRAN 5
– ICATS team has access to MODTRAN 4P beta
Effects of Aeresol
Ground Downwelling
Ground Upwelling
Satellite Upwelling
Degree of Linear Polarization
Effects of Gases
Ground Downwelling
Ground Upwelling
Satellite Upwelling
Degree of Linear Polarization
Future Plans
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Simulations of test scenes
Identify surfaces given Stokes parameters
Measurement capability
Validation of
both VLIDORT and
MODTRAN 4P
Acknowledgements
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Dr. Carol Bruegge, Mentor
Vijay Natraj, VLIDORT expert
Rob Spurr, VLIDORT author
SURF office for program organization
References
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D. Diner, A. Davis, R. Chipman, “Innovative Technology Approach for HighAccuracy Imaging Spectropolarimetry at Multiple View Angles,” project
proposal for funding, 2006.
Spurr, Robert J.D. VLIDORT: A linearized pseudo-spherical vector discrete
ordinate radiative transfer model for forward model and retrieval studies in
multilayer multiple scattering media. JQSRT 2006 in press.
T. Takashima, K. Masuda, “Degree of radiance and polarization of upwelling
radiation from an atmosphere-ocean system”, Applied Optics 24, 15, 2423
(1985)
T. Cronin, E. Warrant, B Greiner, “Celestial polarization patterns during
twilight”, Applied Optics 45, 22, 5582 (2006)
G.N. Plass, G.W. Kattawar, “Polarization of the Radiation Reflected and
Transmitted by the Earth’s Atmosphere”, Applied Optics 9, 5, 1122 (1970)
J. S. Tyo, D. L. Goldstein, D. B. Chenault, J. A. Shaw, “Review of passive
imaging polarimetry for remote sensing applications”, Applied Optics 45, 22,
5453 (2006