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Nonlinear Horizontal Diffusion for GCMs

Becker, Erich und Burkhardt, Ulrike (2007) Nonlinear Horizontal Diffusion for GCMs. Monthly Weather Review, 135, Seiten 1439-1454. DOI: 10.1175/MWR3348.1.

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Kurzfassung

The mixing-length-based parameterization of horizontal diffusion, which was originally proposed by Smagorinsky, is revisited. The complete tendencies of horizontal momentum diffusion, the associated frictional heating, and horizontal diffusion of sensible heat in spherical geometry are derived. The formulations are modified for the terrain-following vertical-hybrid-coordinate system in a way that ensures energy and angular momentum conservation at each layer. Test simulations with a simple general circulation model, run at T42 horizontal resolution and for permanent January conditions, confirm the conservation properties and highlight the enhancement of nonlinear horizontal diffusion in areas of high baroclinic activity. The simulated internal variability is dependent on the nature of the horizontal diffusion, with high-frequency variability being enhanced over the northern continents and low-frequency variability being increased (decreased) over the Pacific (Atlantic) Ocean when using nonlinear rather than linear diffusion. Locally reduced horizontal dissipation over Europe is compensated by increased dissipation owing to vertical diffusion, indicating the potential importance of nonlinear horizontal diffusion for gravity wave–resolving simulations. Inspection of the spectral energy reveals that the scheme needs to be modified in order to damp unbalanced ageostrophic motions at the smallest resolved scales more efficiently. A corresponding empirical modification is proposed and proves to work properly.

Dokumentart:Zeitschriftenbeitrag
Titel:Nonlinear Horizontal Diffusion for GCMs
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Becker, ErichIAP Kühlungsborn
Burkhardt, UlrikeNICHT SPEZIFIZIERT
Datum:April 2007
Erschienen in:Monthly Weather Review
Referierte Publikation:Ja
In Open Access:Nein
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:135
DOI :10.1175/MWR3348.1
Seitenbereich:Seiten 1439-1454
Status:veröffentlicht
Stichwörter:nonlinear Diffusion, climate model, dissipative heating
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 Atmosphären- und Klimaforschung (alt)
Standort: Oberpfaffenhofen
Institute & Einrichtungen:Institut für Physik der Atmosphäre > Dynamik der Atmosphäre
Hinterlegt von: Dr.rer.nat. Ulrike Burkhardt
Hinterlegt am:26 Jun 2007
Letzte Änderung:20 Okt 2014 14:31

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