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Radiometric calibration of IR Fourier transform spectrometers - Solution to a problem with the High-Resolution Interferometer SounderA calibrated Fourier transform spectrometer, known as the High-Resolution Interferometer Sounder (HIS), has been flown on the NASA U-2 research aircraft to measure the infrared emission spectrum of the earth. The primary use - atmospheric temperature and humidity sounding - requires high radiometric precision and accuracy (of the order of 0.1 and 1 C, respectively). To meet these requirements, the HIS instruments, the HIS instrument performs inflight radiometric calibration, using observations of hot and cold blackbody reference sources as the basis for two-point calibrations at each wavenumber. Initially, laboratory tests revealed a calibration problem with brightness temperature errors as large as 15 C between 600 and 900/cm. The symptom of the problem, which occurred in one of the three spectral bands of HIS, was a source-dependent phase response. Minor changes to the calibration equations completely eliminated the anomalous errors. The new analysis properly accounts for the situation in which the phase response for radiance from the instrument itself differs from that for radiance from an external source. The mechanism responsible for the dual phase response of the HIS instrument is identified as emission from the interferometer beam splitter.
Document ID
19880061281
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Revercomb, Henry E.
(Wisconsin Univ. Madison, WI, United States)
Smith, William L.
(Wisconsin, University Madison, United States)
Buijs, H.
(Bomem, Inc. Vanier, Canada)
Howell, Hugh B.
(NOAA, National Environmental Satellite, Data and Information Service, Madison WI, United States)
Laporte, D. D.
(Santa Barbara Research Center Goleta, CA, United States)
Date Acquired
August 13, 2013
Publication Date
August 1, 1988
Publication Information
Publication: Applied Optics
Volume: 27
ISSN: 0003-6935
Subject Category
Spacecraft Instrumentation
Accession Number
88A48508
Funding Number(s)
CONTRACT_GRANT: NOAA-NA-84DGC00095
CONTRACT_GRANT: NAS5-27608
Distribution Limits
Public
Copyright
Other

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