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| Titel |
Eddy turbulence, the double mesopause, and the double layer of atomic oxygen |
| 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 ; 30, no. 1 ; Nr. 30, no. 1 (2012-01-23), S.251-258 |
| Datensatznummer |
250017177
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| Publikation (Nr.) |
 copernicus.org/angeo-30-251-2012.pdf |
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| Zusammenfassung |
| In this study, we consider the impact of eddy turbulence on temperature and
atomic oxygen distribution when the peak of the temperature occurs in the
upper mesosphere. A previous paper (Vlasov and Kelley, 2010) considered the
simultaneous impact of eddy turbulence on temperature and atomic oxygen
density and showed that eddy turbulence provides an effective mechanism to
explain the cold summer and warm winter mesopause observed at high
latitudes. Also, the prevalent role of eddy turbulence in this case removes
the strong contradiction between seasonal variations of the O density
distribution and the impact of upward/downward motion corresponding to
adiabatic cooling/heating of oxygen atoms. Classically, there is a single
minimum in the temperature profile marking the location of the mesopause.
But often, a local maximum in the temperature is observed in the height
range of 85–100 km, creating the appearance of a double mesopause (Bills
and Gardner, 1993; Yu and She, 1995; Gusev et al., 2006). Our results show
that the relative temperature maximum in the upper mesosphere (and thus the
double mesopause) can result from heating by eddy turbulence. According to
our model, there is a close connection between the extra temperature peak in
the mesosphere and the oxygen atom density distribution. The main feature of
the O density height profile produced by eddy turbulence in our model is a
double peak instead of a single peak of O density. A rocket experiment
called TOMEX confirms these results (Hecht et al., 2004). Applying our model
to the results of the TOMEX rocket campaign gives good agreement with both
the temperature and oxygen profiles observed. Climatology of the midlatitude
mesopause and green line emission shows that the double mesopause and the
double layers of the green line emission, corresponding to the double O
density height profile, are mainly observed in spring and fall (Yu and She,
1995; Liu and Shepherd, 2006). Further observations of the oxygen atom
densities and the double mesopause would improve our understanding of the
impact of turbulence on critical mesospheric parameters. |
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