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

Water vapour variability within a convective boundary layer assessed by Large Eddy Simulations and IHOP_2002 observations

Couvreux, F. und Guichard, F. und Redelsperger, J.-L. und Kiemle, Ch. und Masson, V. und Lafore, J.-P. und Flamant, C. (2005) Water vapour variability within a convective boundary layer assessed by Large Eddy Simulations and IHOP_2002 observations. Quarterly Journal of the Royal Meteorological Society, 131, Seiten 2665-2693. DOI: 10.1256/qj.04.167.

[img] PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
969kB

Offizielle URL: http://www3.interscience.wiley.com/cgi-bin/abstract/113522716/ABSTRACT?CRETRY=1&SRETRY=0

Kurzfassung

This study presents a comprehensive analysis of the variability of water vapour in a growing convective boundary-layer (CBL) over land, highlighting the complex links between advection, convective activity and moisture heterogeneity in the boundary layer. A Large-eddy Simulation (LES) is designed, based on observations, and validated, using an independent data-set collected during the International H2O Project (IHOP_2002) field-experiment. Ample information about the moisture distribution in space and time, as well as other important CBL parameters are acquired by mesonet stations, balloon soundings, instruments on-board two aircraft and the DLR airborne water-vapour differential-absorption lidar. Because it can deliver two-dimensional cross-sections at high spatial resolution (140 m horizontal, 200 m vertical), the airborne lidar offers valuable insights of small-scale moisture-variability throughout the CBL. The LES is able to reproduce the development of the CBL in the morning and early afternoon, as assessed by comparisons of simulated mean profiles of key meteorological variables with sounding data. Simulated profiles of the variance of water-vapour mixing-ratio were found to be in good agreement with the lidar-derived counterparts. Finally, probability-density functions of potential temperature, vertical velocity and water-vapour mixing-ratio calculated from the LES show great consistency with those derived from aircraft in situ measurements in the middle of the CBL. Downdraughts entrained from above the CBL are governing the scale of moisture variability. Characteristic length-scales are found to be larger for water-vapour mixing-ratio than for temperature The observed water-vapour variability exhibits contributions from different scales. The influence of the mesoscale (larger than LES domain size, i.e. 10 km) on the smaller-scale variability is assessed using LES and observations. The small-scale variability of water vapour is found to be important and to be driven by the dynamics of the CBL. Both lidar observations and LES evidence that dry downdraughts entrained from above the CBL are governing the scale of moisture variability. Characteristic length-scales are found to be larger for water-vapour mixing-ratio than for temperature and vertical velocity. In particular, intrusions of drier free-troposphere air from above the growing CBL impose a marked negative skewness on the water-vapour distribution within it, both as observed and in the simulation. Copyright © 2005 Royal Meteorological Society.

Dokumentart:Zeitschriftenbeitrag
Titel:Water vapour variability within a convective boundary layer assessed by Large Eddy Simulations and IHOP_2002 observations
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Couvreux, F.CNRM/GAME, F
Guichard, F.CNRM/GAME, F
Redelsperger, J.-L.CNRM/GAME, F
Kiemle, Ch.NICHT SPEZIFIZIERT
Masson, V.CNRM/GAME, F
Lafore, J.-P.CNRM/GAME, F
Flamant, C.IPSL/SA, F
Datum:2005
Erschienen in:Quarterly Journal of the Royal Meteorological Society
Referierte Publikation:Ja
In Open Access:Nein
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:131
DOI :10.1256/qj.04.167
Seitenbereich:Seiten 2665-2693
Status:veröffentlicht
Stichwörter:water vapour lidar, convective boundary layer, IHOP_2002 campaign, Heterogeneities, High-resolution simulations, Humidity Lidar data
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Luftfahrt
HGF - Programmthema:L VU - Luftverkehr und Umwelt (alt)
DLR - Schwerpunkt:Luftfahrt
DLR - Forschungsgebiet:L VU - Luftverkehr und Umwelt
DLR - Teilgebiet (Projekt, Vorhaben):L - Luftverkehr und Wetter (alt)
Standort: Oberpfaffenhofen
Institute & Einrichtungen:Institut für Physik der Atmosphäre > Lidar
Hinterlegt von: Christiane Münster
Hinterlegt am:31 Jul 2007
Letzte Änderung:11 Nov 2014 21:56

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.