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High resolution DNS of jet stream generated tropopausal turbulence
Author(s) -
Joseph B.,
Mahalov A.,
Nicolaenko B.,
Tse K. L.
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl017252
Subject(s) - turbulence , richardson number , physics , reynolds number , jet (fluid) , buoyancy , mechanics , direct numerical simulation , scaling , maxima and minima , maxima , mixing (physics) , turbulence kinetic energy , geometry , mathematics , art , mathematical analysis , quantum mechanics , performance art , art history
Tropopausal turbulence (TT), generated by jet streams, is examined, for different nonhomogeneous basic state forcing profiles, through high resolution three‐dimensional (3D) direct numerical simulations (DNS). Turbulent core regions, on either side of the jet, are characterized by a dramatic decrease in Brunt‐Väisälä frequency ( N ), minima in gradient Richardson number ( Ri g ) and shear length scales, and maxima in buoyancy Reynolds number and buoyancy length scales. The edges of turbulent mixing layers are marked by N 2 ‐bulges, which provides an alternate mechanism for multiple tropopauses. While temperature variance peaks in the vicinity of these N 2 ‐bulges, velocity variances peak within the turbulent core. Multiple branches in the scaling of flux Richardson number with Ri g are found typical for TT, a result having implications to the problem of turbulence parameterization.