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Characteristics of stratospheric turbulent layers measured by LITOS and their relation to the Richardson number
Author(s) -
Haack A.,
Gerding M.,
Lübken F.J.
Publication year - 2014
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2013jd021008
Subject(s) - turbulence , dissipation , stratosphere , altitude (triangle) , richardson number , atmospheric sciences , meteorology , turbulence kinetic energy , range (aeronautics) , resolution (logic) , physics , environmental science , thermodynamics , mathematics , materials science , geometry , computer science , artificial intelligence , composite material
Based on high‐resolution turbulence measurements performed with the newly established balloon‐borne instrument Leibniz Institute Turbulence Observations in the Stratosphere (LITOS) during the Balloon Experiments for University Students (BEXUS) 6 and BEXUS 8 campaigns from Kiruna, we derived characteristics of stratospheric turbulence layers, like their thickness and distance in between. Typically, the layers are ∼15–130 m thick and have a distance of ∼60–270 m, and their number increases with altitude. Due to the very high measurement resolution of LITOS in the range of millimeters, we obtain energy dissipation rate profiles with unprecedented precision. Within the turbulent layers we get a mean dissipation rate of 3.4×10 −2 W/kg (BEXUS 6) and 1.1 × 10 −2 W/kg (BEXUS 8) corresponding to a heating rate of 1 to ∼3 K/d. The profiles show an increase of the energy dissipation with altitude. Comparisons with the Richardson number R i preclude a clear correlation between the occurrence of turbulence and R i <1/4. Despite the expected occurrence of turbulence at R i <1/4, we also observed turbulent layers where R i was >1/4 and far beyond, independent of the scale over which R i has been determined.