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Titel |
Atmospheric aerosol characterization with a ground-based SPEX spectropolarimetric instrument |
VerfasserIn |
G. van Harten, J. De Boer, J. H. H. Rietjens, A. Di Noia, F. Snik, H. Volten, J. M. Smit, O. P. Hasekamp, J. S. Henzing, C. U. Keller |
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. 12 ; Nr. 7, no. 12 (2014-12-10), S.4341-4351 |
Datensatznummer |
250115988
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Publikation (Nr.) |
copernicus.org/amt-7-4341-2014.pdf |
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Zusammenfassung |
Characterization of atmospheric aerosols is important for understanding their
impact on health and climate. A wealth of aerosol parameters can be retrieved
from multi-angle, multi-wavelength radiance and polarization measurements of
the clear sky. We developed a ground-based SPEX instrument (groundSPEX) for
accurate spectropolarimetry, based on the passive, robust, athermal, and
snapshot spectral polarization modulation technique, and is hence ideal for
field deployment. It samples the scattering phase function in the principal
plane in an automated fashion, using a motorized pan/tilt unit and automatic
exposure time detection. Extensive radiometric and polarimetric calibrations
were performed, yielding values for both random noise and systematic
uncertainties. The absolute polarimetric accuracy at low degrees of
polarization is established to be ~5 × 10−3. About 70 measurement
sequences have been performed throughout four clear-sky days at Cabauw, the
Netherlands. Several aerosol parameters were retrieved: aerosol optical
thickness, effective radius, and complex refractive index for fine and coarse
mode. The results are in good agreement with the colocated AERONET products,
with a correlation coefficient of ρ = 0.932 for the total aerosol optical
thickness at 550 nm. |
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