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| Titel |
High Static Stability in the Mixed Layer Above the Extratropical Tropopause |
| VerfasserIn |
A. Kunz, P. Konopka, R. Müller, L. L. Pan, C. Schiller |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023283
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| Zusammenfassung |
| A strong relationship between the static stability N2 in the tropopause inversion layer (TIL)
and the intensity of mixing is evident from in–situ observations during SPURT. With a new
simple measure of mixing intensity based on O3/CO tracer correlations, a very
high mixing intensity connected to a high N2 is found in the extratropical mixing
layer.
Using radiative transfer calculations we simulate the influence of trace gases such as O3
and H2O on the temperature gradient and thus on the static stability above the tropopause in
an idealized (L–shaped) non–mixed and reference mixed atmosphere. N2 enhances due to an
intensifying mixing in the LS. At the same time the temperature decreases together with a
development of an inversion and the TIL. Hereby H2O plays the dominant role in
maintenance the temperature inversion and the TIL structure. In case of non mixed profiles
the TIL vanishes.
The results motivate a link between the mixing layer and the TIL. The mixing
layer contains on the one hand older air masses, with high values of N2 due to
radiative adjustment. This part of the mixing layer is spatial identically to the TIL.
On the other hand, there are younger air masses with somehow lower N2 values
within the mixing layer, because of fast intrusion processes from the troposphere
due to the permeability or so–called mid–latitude–breaks associated with the jet. |
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