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

On the spectrum of atmospheric motions (Ludwig-Prandtl Memorial Lecture

Schumann, Ulrich (2021) On the spectrum of atmospheric motions (Ludwig-Prandtl Memorial Lecture. 91st Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM 2020/21), 2021-03-15 - 2021-03-19, Kassel, Germany (online).

[img] PDF
6MB

Kurzfassung

Spectra of atmospheric motions describe the distribution of kinetic and potential energy as a function of scales. The spectrum of horizontal motions in the free troposphere and the lower stratosphere at horizontal scales from a few 10 m to several 1000 km has often been shown to follow a power law with logarithmic spectral slopes near -3 at large scales and near -5/3 at smaller scales. The motions are highly anisotropic. Inertial subrange turbulence occurs only occasionally. The horizontal spectrum of vertical velocity has been discussed relatively little. Vertical wind drives conversion between potential and kinetic energy, vertical fluxes, cloud formation and turbulence. This study started from measurements of velocity and temperature spectra in field campaigns investigating atmospheric dynamics over oceans and mountains with the DLR research aircraft HALO. Accurate measurements are demanding because the wind speed is often small compared to the aircraft speed. The measured spectrum of vertical velocity showed unexpected peaks at scales corresponding to the depth of the atmosphere. We discuss the Helmholtz decomposition of horizontal velocity in rotational and divergent velocity components. We then show that the horizontal spectrum of vertical velocity is kinematically connected to the spectrum of horizontal divergent motions. The observed peaks occur when the divergent motions are vertically coherent and when the horizontal spectrum of divergent velocity reaches spectral slopes larger than -2. Details can be found in a recent publication (J. Atmos. Sci., 2019, doi: 10.1175/JAS-D-19-0160.1). This lecture is dedicated to Ludwig Prandtl (1875-1953) who contributed fundamentally to fluid mechanics, including meteorology.

elib-URL des Eintrags:https://elib.dlr.de/141352/
Dokumentart:Konferenzbeitrag (Vortrag)
Titel:On the spectrum of atmospheric motions (Ludwig-Prandtl Memorial Lecture
Autoren:
AutorenInstitution oder E-Mail-AdresseAutoren-ORCID-iDORCID Put Code
Schumann, UlrichDLR, IPAhttps://orcid.org/0000-0001-5255-6869NICHT SPEZIFIZIERT
Datum:2021
Referierte Publikation:Nein
Open Access:Ja
Gold Open Access:Nein
In SCOPUS:Nein
In ISI Web of Science:Nein
Status:veröffentlicht
Stichwörter:kinetic energy, vertical velocity, airborne measurements, Helmholtz decomposition, turbulence
Veranstaltungstitel:91st Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM 2020/21)
Veranstaltungsort:Kassel, Germany (online)
Veranstaltungsart:internationale Konferenz
Veranstaltungsbeginn:15 März 2021
Veranstaltungsende:19 März 2021
Veranstalter :GAMM and DGLR
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Raumfahrt
HGF - Programmthema:Erdbeobachtung
DLR - Schwerpunkt:Raumfahrt
DLR - Forschungsgebiet:R EO - Erdbeobachtung
DLR - Teilgebiet (Projekt, Vorhaben):R - Atmosphären- und Klimaforschung
Standort: Oberpfaffenhofen
Institute & Einrichtungen:Institut für Physik der Atmosphäre
Hinterlegt von: Schumann, Prof.Dr.habil. Ulrich
Hinterlegt am:17 Mär 2021 10:16
Letzte Änderung:24 Apr 2024 20:41

Nur für Mitarbeiter des Archivs: Kontrollseite des Eintrags

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