elib
DLR-Header
DLR-Logo -> http://www.dlr.de
DLR Portal Home | Impressum | Kontakt | English
Schriftgröße: [-] Text [+]

In situ measurements of tropical cloud properties in the West African Monsoon: upper tropospheric ice clouds, Mesoscale Convective System outflow, and subvisual cirrus

Frey, W. und Borrmann, S. und Kunkel, D. und Weigel, R. und de Reus, M. und Schlager, H. und Roiger, A. und Voigt, C. und Hoor, P. und Curtius, J. und Krämer, M. und Schiller, C. und Volk, C. M. und Homan, C. D. und Fierli, F. und Di Donfrancesco, G. und Ulanovsky, A. und Ravegnani, F. und Sitnikov, M.N. und Viciani, S. und D’Amato, F. und Shur, G. und Belyaev, D. und Law, K. S. und Cairo, F. (2011) In situ measurements of tropical cloud properties in the West African Monsoon: upper tropospheric ice clouds, Mesoscale Convective System outflow, and subvisual cirrus. Atmospheric Chemistry and Physics, 11, Seiten 5569-5590. DOI: 10.5194/acp-11-5569-2011.

[img] PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
874kB

Offizielle URL: http://www.atmos-chem-phys.net/11/5569/2011/

Kurzfassung

In situ measurements of ice crystal size distributions in tropical upper troposphere/lower stratosphere (UT/LS) clouds were performed during the SCOUT-AMMA campaign overWest Africa in August 2006. The cloud properties were measured with a Forward Scattering Spectrometer Probe (FSSP-100) and a Cloud Imaging Probe (CIP) operated aboard the Russian high altitude research aircraft M-55 Geophysica with the mission base in Ouagadougou, Burkina Faso. A total of 117 ice particle size distributions were obtained from the measurements in the vicinity of Mesoscale Convective Systems (MCS). Two to four modal lognormal size distributions were fitted to the average size distributions for different potential temperature bins. The measurements showed proportionately more large ice particles compared to former measurements above maritime regions. With the help of trace gas measurements of NO, NOy, CO2, CO, and O3 and satellite images, clouds in young and aged MCS outflow were identified. These events were observed at altitudes of 11.0 km to 14.2 km corresponding to potential temperature levels of 346K to 356 K. In a young outflow from a developing MCS ice crystal number concentrations of up to (8.3±1.6) cm−3 and rimed ice particles with maximum dimensions exceeding 1.5mm were found. A maximum ice water content of 0.05 gm−3 was observed and an effective radius of about 90 μm. In contrast the aged outflow events were more diluted and showed a maximum number concentration of 0.03 cm−3, an ice water content of 2.3×10−4 gm−3, an effective radius of about 18 μm, while the largest particles had a maximum dimension of 61 μm. Close to the tropopause subvisual cirrus were encountered four times at altitudes of 15 km to 16.4 km. The mean ice particle number concentration of these encounters was 0.01 cm−3 with maximum particle sizes of 130 μm, and the mean ice water content was about 1.4×10−4 gm−3. All known in situ measurements of subvisual tropopause cirrus are compared and an exponential fit on the size distributions is established for modelling purposes. A comparison of aerosol to ice crystal number concentrations, in order to obtain an estimate on how many ice particles may result from activation of the present aerosol, yielded low ratios for the subvisual cirrus cases of roughly one cloud particle per 30 000 aerosol particles, while for the MCS outflow cases this resulted in a high ratio of one cloud particle per 300 aerosol particles.

Dokumentart:Zeitschriftenbeitrag
Titel:In situ measurements of tropical cloud properties in the West African Monsoon: upper tropospheric ice clouds, Mesoscale Convective System outflow, and subvisual cirrus
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Frey, W.MPI für Chemie, Mainz
Borrmann, S.MPI für Chemie, Mainz
Kunkel, D.MPI für Chemie, Mainz
Weigel, R.Johannes Gutenberg Univ., Mainz
de Reus, M.Elementar Analysensysteme GmbH, Hanau
Schlager, H.DLR
Roiger, A.DLR
Voigt, C.Johannes Gutenberg Univ., Mainz/DLR
Hoor, P.Johannes Gutenberg Univ., Mainz
Curtius, J.Univ. Frankfurt
Krämer, M.FZ Jülich
Schiller, C.FZ Jülich
Volk, C. M. Univ. Wuppertal
Homan, C. D. Univ. Wuppertal
Fierli, F.ISAC-CNR, Rome, I
Di Donfrancesco, G.l’Energia e l’Ambiente, Frascati, I
Ulanovsky, A.ISTC, Dolgoprudny, Moskow Region, R
Ravegnani, F.ISAC-CNR, Rome, I
Sitnikov, M.N.ISTC, Dolgoprudny, Moskow Region, R
Viciani, S.CNR-INO, Florence, I
D’Amato, F.CNR-INO, Florence, I
Shur, G.ISTC, Dolgoprudny, Moskow Region, R
Belyaev, D.MDB, Moscow Region, R
Law, K. S.KNMI, De Bilt, NL
Cairo, F.ISAC-CNR, Rome, I
Datum:2011
Erschienen in:Atmospheric Chemistry and Physics
Referierte Publikation:Ja
In Open Access:Ja
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:11
DOI :10.5194/acp-11-5569-2011
Seitenbereich:Seiten 5569-5590
Status:veröffentlicht
Stichwörter:ice crystal size distributions
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr, Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Raumfahrt, Luftfahrt
HGF - Programmthema:Erdbeobachtung, ATM und Flugbetrieb
DLR - Schwerpunkt:Raumfahrt, Luftfahrt
DLR - Forschungsgebiet:R EO - Erdbeobachtung, L AO - Luftverkehrsmanagement und Flugbetrieb
DLR - Teilgebiet (Projekt, Vorhaben):R - Vorhaben Atmosphären- und Klimaforschung, L - Klima, Wetter und Umwelt
Standort: Oberpfaffenhofen
Institute & Einrichtungen:Institut für Physik der Atmosphäre > Atmosphärische Spurenstoffe
Hinterlegt von: Jana Freund
Hinterlegt am:17 Nov 2011 15:33
Letzte Änderung:26 Mär 2013 13:33

Nur für Mitarbeiter des Archivs: Kontrollseite des Eintrags

Blättern
Suchen
Hilfe & Kontakt
Informationen
electronic library verwendet EPrints 3.3.12
Copyright © 2008-2013 Deutsches Zentrum für Luft- und Raumfahrt (DLR). Alle Rechte vorbehalten.