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The spectrum of waves and turbulence at the tropopause
Author(s) -
Duck Thomas J.,
Whiteway James A.
Publication year - 2005
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 - 10.1029/2004gl021189
Subject(s) - turbulence , turbulence kinetic energy , wavelength , tropopause , physics , kinetic energy , equipartition theorem , altitude (triangle) , gravity wave , atmospheric sciences , wave turbulence , spectral line , gravitational wave , troposphere , computational physics , meteorology , geology , optics , astrophysics , classical mechanics , geometry , astronomy , magnetic field , mathematics , quantum mechanics
Aircraft measurements of winds, temperatures, and composition were conducted with a high‐altitude aircraft in the tropopause region above Northern Wales during May and June 2000. Observations on 6 June 2000 along three vertically stacked horizontal flight legs show fluctuations due to both gravity waves and turbulence. Horizontal kinetic energy spectra determined from the measurements extend to 3 m in wavelength, the smallest scales yet available at these heights. The vertical wind spectrum for strong turbulence is considerably different in both shape and intensity from the non‐turbulent spectrum. A sharp knee in the turbulent spectrum at 100 m wavelength is associated with the equipartition of kinetic energy in three dimensions. At other scales the vertical motions are relatively suppressed. A wave with 500 m wavelength was found, and provides a transition between the turbulent and non‐turbulent cases.