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| Titel |
A new airborne Polar Nephelometer for the measurement of optical and microphysical cloud properties. Part II: Preliminary tests |
| VerfasserIn |
O. Crépel, J.-F. Gayet, J.-F. Fournol, S. Oshchepkov |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 15, no. 4 ; Nr. 15, no. 4, S.460-470 |
| Datensatznummer |
250012732
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| Publikation (Nr.) |
 copernicus.org/angeo-15-460-1997.pdf |
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| Zusammenfassung |
| A new optical sensor, the airborne Polar
Nephelometer, has been tested in an open wind tunnel. The wind tunnel was
operated in cloudy conditions including either cloud water droplets or ice
crystals, or a mixture of these particles. The sensor is designed to measure the
optical and microphysical parameters of cloud particles sized from a few
micrometers to about 500 µm diameter. Basically, the probe measures the
scattering phase function of an ensemble of cloud particles which intersect a
collimated laser beam near the focal point of a paraboloidal mirror. From the
measured scattering phase function the retrieval of the droplet-size spectra and
subsequent derived quantities such as liquid water content and size parameters
can be calculated using an inversion method. The particle phase discrimination
(water droplets/ice particles) can be derived from the shape of the scattering
phase function and the sensitivity of the probe allows the detection of small
ice crystals (typically of 5 µm diameter). The paper describes the preliminary
results obtained by the prototype version of the Polar Nephelometer in various
cloudy conditions. These results are compared with direct microphysical
measurements obtained by usual PMS probes also mounted in the wind tunnel.
Complementary results obtained in a cold chamber are presented in order to
illustrate the reliability of the Polar Nephelometer in the presence of small
ice crystals. |
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