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Titel |
Validation of spectral sky radiance derived from all-sky camera images – a case study |
VerfasserIn |
K. Tohsing, M. Schrempf, S. Riechelmann, G. Seckmeyer |
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 ; 7, no. 7 ; Nr. 7, no. 7 (2014-07-16), S.2137-2146 |
Datensatznummer |
250115848
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Publikation (Nr.) |
copernicus.org/amt-7-2137-2014.pdf |
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Zusammenfassung |
Spectral sky radiance (380–760 nm) is derived from
measurements with a hemispherical sky imager (HSI) system. The HSI
consists of a commercial compact CCD (charge coupled device) camera
equipped with a fish-eye lens and provides hemispherical sky images
in three reference bands such as red, green and blue. To obtain the
spectral sky radiance from these images, non-linear regression
functions for various sky conditions have been derived. The camera-based
spectral sky radiance was validated using spectral sky radiance measured with
a CCD spectroradiometer. The spectral sky radiance for complete
distribution over the hemisphere between both instruments deviates
by less than 20% at 500 nm for all sky conditions and
for zenith angles less than 80°. The reconstructed spectra of
the wavelengths 380–760 nm between both
instruments at various directions deviate by less than 20% for
all sky conditions. |
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