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Quantification of stratospheric mixing from turbulence microstructure measurements
Author(s) -
Alisse JeanRémi,
Haynes Peter H.,
Vanneste Jacques,
Sidi Claude
Publication year - 2000
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 - 10.1029/2000gl011386
Subject(s) - thermal diffusivity , turbulence , stratosphere , mixing (physics) , range (aeronautics) , geology , atmospheric sciences , mechanics , meteorology , environmental science , materials science , physics , thermodynamics , quantum mechanics , composite material
In the stratosphere, turbulence is confined within shallow, localised patches. The resulting vertical mixing of tracers is highly intermittent and difficult to quantify. Here a new technique is employed to estimate from high‐resolution, lower stratospheric mid‐latitude balloon data a well‐defined vertical diffusivity associated with this mixing. The technique, which is based on a stochastic model of the distribution of turbulent patches, emphasises the dependence of the diffusivity on the typical patch lifetime. Assuming a lifetime of a few hours, the diffusivity is found to be in the range 0.01–0.02m²s −1 . This value is an order of magnitude smaller than those previously derived from radar measurements. The potential of the technique for the analysis of ocean microstructure measurements is noted.