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Titel |
The in-flight blackbody calibration system for the GLORIA interferometer on board an airborne research platform |
VerfasserIn |
F. Olschewski, A. Ebersoldt, F. Friedl-Vallon, B. Gutschwager, J. Hollandt, A. Kleinert, C. Monte, C. Piesch, P. Preusse, C. Rolf, P. Steffens, R. Koppmann |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1867-1381
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Measurement Techniques ; 6, no. 11 ; Nr. 6, no. 11 (2013-11-12), S.3067-3082 |
Datensatznummer |
250085106
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Publikation (Nr.) |
copernicus.org/amt-6-3067-2013.pdf |
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Zusammenfassung |
The Gimballed Limb Observer for
Radiance Imaging of the Atmosphere (GLORIA)
is a prototype of an imaging Fourier Transform Spectrometer (FTS) for
PREMIER, a former candidate mission for ESA's Earth Explorer 7. GLORIA is
deployed on board various research aircraft such as the Russian M55
Geophysica or the German HALO. The instrument provides detailed
infrared images of the Upper Troposphere/Lower Stratosphere (UTLS)
region, which plays a crucial role in the climate system. GLORIA uses
a two-dimensional detector array for infrared limb observations in
emission and therefore needs large-area blackbody radiation sources
(126 mm × 126 mm) for calibration.
In order to meet the highly demanding uncertainty requirements for the
scientific objectives of the GLORIA missions and due to the
sophisticated tomographic evaluation scheme, the spatial distribution
of the radiance temperature of the blackbody calibration sources has
to be determined with an uncertainty of about 0.1 K. Since
GLORIA is exposed to the hostile environment of the UTLS with mutable
low temperature and pressure, an in-flight calibration system has to
be carefully designed to cope with those adverse circumstances.
The GLORIA in-flight calibration system consists of two identical
weight-optimised high-precision blackbody radiation sources, which are
independently stabilised at two different temperatures. The two point
calibration is in the range of the observed atmospheric infrared
radiance emissions with 10 K below and 30 K above
ambient temperature, respectively. Thermo-Electric Coolers are used to
control the temperature of the blackbody radiation sources offering
the advantage of avoiding cryogens and mechanical coolers. The design
and performance of the GLORIA in-flight calibration system is
presented. The blackbody calibration sources have been comprehensively
characterised for their spatially (full aperture) and spectrally
(7 to 13 μm) resolved radiation properties in
terms of radiance temperatures traceable to the International
Temperature Scale (ITS-90) at the Physikalisch-Technische
Bundesanstalt (PTB), the national metrology institute of Germany. |
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