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

Gap flows: Results from the Mesoscale Alpine Programme

Mayr, Georg J. und Armi, Laurence und Gohm, Alexander und Zängl, Günther und Durran, Dale R. und Flamant, Cyrille und Gabersek, Sasa und Mobbs, Stephen und Ross, Andrew und Weissmann, Martin (2007) Gap flows: Results from the Mesoscale Alpine Programme. Quarterly Journal of the Royal Meteorological Society, 133, Seiten 881-895. DOI: 10.1002/qj.66.

[img]
Vorschau
PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
2MB

Offizielle URL: http://www3.interscience.wiley.com/journal/113388514/home

Kurzfassung

An overview of advances in the observation, modelling, forecasting, and understanding of flows through gaps achieved in the Mesoscale Alpine Programme is given. Gaps are lateral constrictions of topography (level gaps) often combined with vertical terrain changes (passes). Of the possible flow configurations, only an asymmetric one (relatively deep and slow upstream, accelerating and thinning downstream), which connects two different reservoirs on each side of the gap, is examined. The flow is strongly nonlinear, making hydraulics (reduced-gravity shallow-water theory) rather than linear theory the simplest conceptual model to describe gap flow. Results from idealized topographical and flow conditions are presented, together with gap flows through a pass in the central Alpine Wipp Valley. For a given depth of the upstream reservoir, the gap controls the mass flux through it and marks the transition from a subcritical flow state upstream to a supercritical one downstream, which eventually adjusts to the downstream reservoir in a hydraulic jump. Three gap flow prototypes were found: a classical layer one with neutral stratification and a capping inversion and two with a continuous stratification, for which a special analytical self-similar hydraulic solution exists. In all three cases, a deepening wedge of nearly mixed and stagnant air forms on top of the gap flow plunging down from the pass. The descent causes a warming and (relative) drying of the air, making gap flows a special case of föhn. Topographical variations smaller than the gap scale cause additional hydraulic jumps, flow separation, vorticity banners, gravity waves, and interactions with cold pools. Turbulent friction cannot be neglected. The climatological frequency of gap flows depends on the establishment of two different reservoirs and reaches 20% for the Wipp

Dokumentart:Zeitschriftenbeitrag
Titel:Gap flows: Results from the Mesoscale Alpine Programme
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Mayr, Georg J.Univ. Innsbruck, Innsbruck, A
Armi, LaurenceUniv. of California, San Diego, La Jolla, CA, USA
Gohm, AlexanderUniv. Innsbruck, Innsbruck
Zängl, GüntherUniv. München, München
Durran, Dale R.Univ. of Washington, USA
Flamant, CyrilleInstitute Pierre Simon Laplace, F
Gabersek, SasaUniv. of Ljubljana, SLO
Mobbs, StephenUniv. of Leeds, UK
Ross, AndrewUniv. of Leeds, UK
Weissmann, MartinNICHT SPEZIFIZIERT
Datum:Februar 2007
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:133
DOI :10.1002/qj.66
Seitenbereich:Seiten 881-895
Status:veröffentlicht
Stichwörter:mountain, constriction, hydraulics, föhn
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:13 Mär 2008
Letzte Änderung:20 Okt 2014 14:32

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.