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Titel |
First correlated measurements of the shape and light scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS) probe |
VerfasserIn |
A. Abdelmonem, M. Schnaiter, P. Amsler, E. Hesse, J. Meyer, T. Leisner |
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 ; 4, no. 10 ; Nr. 4, no. 10 (2011-10-12), S.2125-2142 |
Datensatznummer |
250002113
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Publikation (Nr.) |
copernicus.org/amt-4-2125-2011.pdf |
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Zusammenfassung |
Studying the radiative impact of cirrus clouds requires knowledge of the
relationship between their microphysics and the single scattering properties
of cloud particles. Usually, this relationship is obtained by modeling the
optical scattering properties from in situ measurements of ice crystal size
distributions. The measured size distribution and the assumed particle shape
might be erroneous in case of non-spherical ice particles. We present here a
novel optical sensor (the Particle Habit Imaging and Polar Scattering probe,
PHIPS) designed to measure simultaneously the 3-D morphology and the
corresponding optical and microphysical parameters of individual cloud
particles. Clouds containing particles ranging from a few micrometers to
about 800 μm diameter in size can be characterized systematically with
an optical resolution power of 2 μm and polar scattering resolution of
1° for forward scattering directions (from 1° to 10°) and
8° for side and backscattering directions (from 18° to 170°). The
maximum acquisition rates for scattering phase functions and images are
262 KHz and 10 Hz, respectively. Some preliminary results collected in two ice
cloud campaigns conducted in the AIDA cloud simulation chamber are
presented. PHIPS showed reliability in operation and produced size
distributions and images comparable to those given by other certified cloud
particles instruments. A 3-D model of a hexagonal ice plate is constructed
and the corresponding scattering phase function is compared to that modeled
using the Ray Tracing with Diffraction on Facets (RTDF) program. PHIPS is a
highly promising novel airborne optical sensor for studying the radiative
impact of cirrus clouds and correlating the particle habit-scattering
properties which will serve as a reference for other single, or
multi-independent, measurement instruments. |
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