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Polarization in the OCO Retrieval Algorithm Vijay Natraj California Institute of Technology March 22, 2005 Objectives Test polarization code and perform timing tests Study effect of viewing geometry and surface albedo on reflectance errors
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Polarization in the OCO Retrieval Algorithm Vijay Natraj California Institute of Technology March 22, 2005
Objectives • Test polarization code and perform timing tests • Study effect of viewing geometry and surface albedo on reflectance errors • Gain insights into potential methods of characterizing polarization in a scalar retrieval code
Operational and System Details • Discrete Ordinates RT Code • 11 layer (8 in troposphere) atmosphere • Aerosol optical depth: 0.025 • Single scattering albedo: 0.8 • SZA: 60 degrees • Surface albedo: 0.2
Effect of Viewing Geometry I Red, Green, Blue, Yellow: VZA = 0°, 30°, 60°, 75°
Effect of Viewing Geometry II Red, Green, Blue, Yellow: VZA = 0°, 30°, 60°, 75°
Effect of Viewing Geometry III Red, Green, Blue, Yellow: VZA = 0°, 30°, 60°, 75°
Effect of Surface Albedo I Red, Green: Surface Albedo = 0.05, 0.2
Effect of Surface Albedo II 810 45 Red, Green: Surface Albedo = 0.05, 0.2
Effect of Surface Albedo III Red, Green: Surface Albedo = 0.05, 0.2
Seasonal Variation (Park Falls) I Red (January), Green (July): SZA = 75.1°, 34.8°
Seasonal Variation (Park Falls) II Red (January), Green (July): SZA = 75.1°, 34.8°
Seasonal Variation (Park Falls) III Red (January), Green (July): SZA = 75.1°, 34.8°
Future Work • Perform complete retrieval to produce benchmark results for XCO2 errors if polarization is neglected • Incorporate typical BRDFs • Doubling-adding techniques to speed up computation for low optical depth cases • Estimation of Stokes parameter Q using first few orders of scattering? Level 4