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| Titel |
Lidar characterization of the Arctic atmosphere during ASTAR 2007: four cases studies of boundary layer, mixed-phase and multi-layer clouds |
| VerfasserIn |
A. Lampert, C. Ritter, A. Hoffmann, J.-F. Gayet, G. Mioche, A. Ehrlich, A. Dörnbrack, M. Wendisch, M. Shiobara |
| 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 ; 10, no. 6 ; Nr. 10, no. 6 (2010-03-26), S.2847-2866 |
| Datensatznummer |
250008260
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| Publikation (Nr.) |
 copernicus.org/acp-10-2847-2010.pdf |
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| Zusammenfassung |
| During the Arctic Study of Tropospheric Aerosol, Clouds and Radiation
(ASTAR), which was conducted in Svalbard in March and April 2007,
tropospheric Arctic clouds were observed with two ground-based backscatter
lidar systems (micro pulse lidar and Raman lidar) and with an airborne
elastic lidar. In the time period of the ASTAR 2007 campaign, an increase in
low-level cloud cover (cloud tops below 2.5 km) from 51% to 65% was
observed above Ny-Ålesund. Four different case studies of lidar cloud
observations are analyzed: With the ground-based Raman lidar, a layer of
spherical particles was observed at an altitude of 2 km after the
dissolution of a cloud. The layer probably consisted of small hydrated
aerosol (radius of 280 nm) with a high number concentration (around
300 cm−3) at low temperatures (−30 °C). Observations of a boundary
layer mixed-phase cloud by airborne lidar and concurrent airborne in situ
and spectral solar radiation sensors revealed the localized process of total
glaciation at the boundary of different air masses. In the free troposphere,
a cloud composed of various ice layers with very different optical
properties was detected by the Raman lidar, suggesting large differences of
ice crystal size, shape and habit. Further, a mixed-phase double layer cloud
was observed by airborne lidar in the free troposphere. Local orography
influenced the evolution of this cloud. The four case studies revealed
relations of cloud properties and specific atmospheric conditions, which we
plan to use as the base for numerical simulations of these clouds. |
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