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Microphysical and optical properties of Arctic mixed-phase clouds. The 9 April 2007 case study

Gayet, J.-F. und Mioche, G. und Dörnbrack, A. und Ehrlich, A. und Lampert, A. und Wendisch, M. (2009) Microphysical and optical properties of Arctic mixed-phase clouds. The 9 April 2007 case study. Atmospheric Chemistry and Physics, 9, Seiten 6581-6595. DOI: 10.5194/acp-9-6581-2009.

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Offizielle URL: http://www.atmos-chem-phys.net/9/6581/2009/

Kurzfassung

Airborne measurements in Arctic boundary-layer stratocumulus were carried out near Spitsbergen on 9 April 2007 during the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) campaign. A unique set of co-located observations is used to describe the cloud properties, including detailed in situ cloud microphysical and radiation measurements along with airborne and co-located spaceborne remote sensing data (CALIPSO lidar and CloudSat radar). CALIPSO profiles indicate cloud top levels at temperature between â��24�°C and â��21�°C. In situ measurements confirm that the cloud-top lidar attenuated backscatter signal along the aircraft trajectory is linked with the presence of liquid water, a common feature observed in Arctic mixed-phase stratocumulus clouds. A low concentration of large ice crystals is also observed up to the cloud top resulting in significant CloudSat radar echoes. Since the ratio of the extinction of liquid water droplets to ice crystals is high, broadband radiative effects near the cloud top are mostly dominated by water droplets. CloudSat observations and in situ measurements reveal high reflectivity factors (up to 15 dBZ) and precipitation rates (1 mm hâ��1). This feature results from efficient ice growth processes. About 25% of the theoretically available liquid water is converted into ice water with large precipitating ice crystals. Using an estimate of mean cloud cover, a considerable value of 106 m3 hâ��1 of fresh water could be settled over the Greenland sea pool. European Centre for Medium-Range Weather Forecast (ECMWF) operational analyses reproduces the boundary layer height variation along the flight track. However, small-scale features in the observed cloud field cannot be resolved by ECMWF analysis. Furthermore, ECMWF's diagnostic partitioning of the condensed water into ice and liquid reveals serious shortcomings for Arctic mixed-phased clouds. Too much ice is modelled.

Dokumentart:Zeitschriftenbeitrag
Titel:Microphysical and optical properties of Arctic mixed-phase clouds. The 9 April 2007 case study
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Gayet, J.-F.Univ. Blaise Pascal, Clermont-Ferrand, F
Mioche, G.Univ. Blaise Pascal, Clermont-Ferrand, F
Dörnbrack, A.DLR
Ehrlich, A.LIM, Leipzig
Lampert, A.AWI, Potsdam
Wendisch, M.LIM, Leipzig
Datum:2009
Erschienen in:Atmospheric Chemistry and Physics
Referierte Publikation:Ja
In Open Access:Ja
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:9
DOI :10.5194/acp-9-6581-2009
Seitenbereich:Seiten 6581-6595
Status:veröffentlicht
Stichwörter:ASTAR, CALIPSO, Arktische Grenzschicht, Mischphasenwolken, Lidar
HGF - Forschungsbereich:Verkehr und Weltraum (alt)
HGF - Programm:Weltraum (alt)
HGF - Programmthema:W EO - Erdbeobachtung
DLR - Schwerpunkt:Weltraum
DLR - Forschungsgebiet:W EO - Erdbeobachtung
DLR - Teilgebiet (Projekt, Vorhaben):W - Vorhaben LIDAR-Forschung und -Entwicklung (alt)
Standort: Oberpfaffenhofen
Institute & Einrichtungen:Institut für Physik der Atmosphäre > Wolkenphysik und Verkehrsmeteorologie
Hinterlegt von: Jana Freund
Hinterlegt am:10 Mai 2010 14:18
Letzte Änderung:12 Dez 2013 20:57

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