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| Titel |
Criterion for analyzing experimental data on eddy diffusion coefficients |
| VerfasserIn |
M. N. Vlasov, M. C. Kelley |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 32, no. 6 ; Nr. 32, no. 6 (2014-06-02), S.581-588 |
| Datensatznummer |
250121065
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| Publikation (Nr.) |
 copernicus.org/angeo-32-581-2014.pdf |
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| Zusammenfassung |
| Problems exist in estimating the eddy heat transport coefficient,
Keh, from experimental data. These problems are due to uncertainty in
determining the turbulent energy dissipation rate and to the uncertainty of
Keh dependence on the energy dissipation rate. In this paper, a new
criterion for estimating the eddy heat transport coefficient is suggested.
This criterion is based on the effect of eddy turbulence on the energy
budget of the upper mesosphere and lower thermosphere. The calculations show
high cooling around and above the Keh peak for Keh values inferred
from experimental data. The cooling rates are much higher than cooling rates
corresponding to the temperature given by the MSIS-E-90 model or to
temperatures measured during the experiments. The main contribution to high
cooling rates is due to the term with eddy heat conduction, which strongly
depends on the Keh gradient. According to our results, the
heating/cooling values below the Keh peak altitude correspond to the temperature given by the
MSIS-E-90 model, but at the peak and above, the cooling rates are larger by
a factor of 2–3 than the rates corresponding to the temperatures. This means
that the Keh values in the peak and above may be overestimated.
Application of this criterion to the Turbulent Oxygen Mixing Experiment
(TOMEX) data shows that eddy diffusions inferred from observing chemical
tracers in TOMEX are strongly overestimated. |
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