Direct spectral measurements with a Brewer spectroradiometer: absolute calibration and aerosol optical depth retrieval
2005; Optica Publishing Group; Volume: 44; Issue: 9 Linguagem: Inglês
10.1364/ao.44.001681
ISSN0003-6935
AutoresStelios Kazadzis, Alkiviadis Bais, Natalia Kouremeti, Evangelos Gerasopoulos, Katerina Garane, M. Blumthaler, B. Schallhart, Alexander Cede,
Tópico(s)Calibration and Measurement Techniques
ResumoWe present three different methods for the absolute calibration of direct spectral irradiances measured with a Brewer spectroradiometer, which are shown to agree to within ±2%. Direct irradiance spectra derived by Brewer and Bentham spectroradiometers agree to within 4 ± 3%. Good agreement was also found by a comparison of the aerosol optical depth and Angstrom exponent retrieved by the two instruments and a multifilter rotational shadowband radiometer. The spectral aerosol optical depth (300–365 nm) derived from six years of direct irradiance measurements at Thessaloniki shows a distinct seasonal variation, averaging to ~0.3 at 340 nm in winter and ~0.7 in summer.
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