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Radiometric calibration of a polarization-sensitive sensorThe radiometric accuracy of a sensor is adversely affected by scene polarization if its optical system is sensitive to polarization. Tests performed on the reflective bands of the NS001 Thematic Mapper simulator, an aircraft multispectral scanner, show that it is very sensitive to the polarization state of the incoming radiations. For 100 percent linearly polarized light, errors in the measured intensity vary from -40 to +40 percent, depending on the scan angle and spectral band. To estimate polarization-induced errors in the intensity measured at aircraft level, the intensity and polarization of the atmospheric radiances were simulated using a realistic earth-atmosphere radiative transfer model. For the polarization of atmospheric radiances in the solar meridian plane over a vegetated target, intensity errors may range from -10 to + 10 percent. The polarization-induced errors are highest in the shortest NS001 spectral band (0.450-0.525 microns) because of large atmospheric polarizations contributed by Rayleigh particles and small diluting effects caused by the small contributions of weakly polarized radiations coming from aerosols and the surface. Depending on the illumination and view angles, the errors in derived surface reflectance due to the radiance errors can be very large. In particular, for large off-nadir view angles in the forward scattered direction when the sun is low, the relative errors in the derived surface reflectance can be as large as 4 to 5 times the relative error in the radiances. Polarization sensitivity errors cannot be neglected for the shorter wavelengths when the surface reflectance contribution to atmospheric radiances is very small.
Document ID
19930036617
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Ahmad, Suraiya P.
(Huges-STX Corp. Lanham, MD, United States)
Markham, Brian L.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 15, 2013
Publication Date
November 30, 1992
Publication Information
Publication: Journal of Geophysical Research
Volume: 97
Issue: D17
ISSN: 0148-0227
Subject Category
Instrumentation And Photography
Accession Number
93A20614
Distribution Limits
Public
Copyright
Other

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