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 m 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 makes objects appear extremely clear regardless

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 Simulations of test scenes Identify surfaces given Stokes parameters Measurement capability Validation of both VLIDORT and MODTRAN 4P

Acknowledgements Dr. Carol Bruegge, Mentor Vijay Natraj, VLIDORT expert Rob Spurr, VLIDORT author SURF office for program organization

References D. Diner, A. Davis, R. Chipman, “Innovative Technology Approach for High- Accuracy Imaging Spectropolarimetry at Multiple View Angles,” project proposal for funding, 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