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| Titel |
Physical properties of High Arctic tropospheric particles during winter |
| VerfasserIn |
L. Bourdages, T. J. Duck, G. Lesins, J. R. Drummond, E. W. Eloranta |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 9, no. 18 ; Nr. 9, no. 18 (2009-09-21), S.6881-6897 |
| Datensatznummer |
250007638
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| Publikation (Nr.) |
 copernicus.org/acp-9-6881-2009.pdf |
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| Zusammenfassung |
| A climatology of particle scattering properties in the wintertime High Arctic
troposphere, including vertical distributions and effective radii, is
presented. The measurements were obtained using a lidar and cloud radar
located at Eureka, Nunavut Territory (80° N, 86° W). Four
different particle groupings are considered: boundary-layer ice crystals,
ice clouds, mixed-phase clouds, and aerosols. Two-dimensional histograms of
occurrence probabilities against depolarization, radar/lidar colour ratio and
height are given. Colour ratios are related to particle minimum dimensions
(i.e., widths rather than lengths) using a Mie scattering model. Ice cloud
crystals have effective radii spanning 25–220 µm, with larger
particles observed at lower altitudes. Topographic blowing snow residuals in
the boundary layer have the smallest crystals at 15–70 µm.
Mixed-phase clouds have water droplets and ice crystal precipitation in the
5–40 µm and 40–220 µm ranges, respectively. Ice cloud
crystals have depolarization decreasing with height. The depolarization trend
is associated with the large ice crystal sub-population. Small crystals
depolarize more than large ones in ice clouds at a given altitude, and show
constant modal depolarization with height. Ice clouds in the mid-troposphere
are sometimes observed to precipitate to the ground. Water clouds are
constrained to the lower troposphere (0.5–3.5 km altitude). Aerosols are
most abundant near the ground and are frequently mixed with the other particle
types. The data are used to construct a classification chart for particle
scattering in wintertime Arctic conditions. |
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