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| Titel |
Overturning instability in the mesosphere and lower thermosphere: analysis of instability conditions in lidar data |
| VerfasserIn |
L. Hurd, M. F. Larsen, A. Z. Liu |
| 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 ; 27, no. 7 ; Nr. 27, no. 7 (2009-07-24), S.2937-2945 |
| Datensatznummer |
250016602
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| Publikation (Nr.) |
 copernicus.org/angeo-27-2937-2009.pdf |
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| Zusammenfassung |
| Resonant sodium lidar measurements from the transition region between the
mesosphere and lower thermosphere have revealed frequently-occurring
overturning events characterized by vertical scales of ~3–6 km and
timescales of several hours. Larsen et al. (2004) proposed that a convective
roll instability, similar to that found in the planetary boundary layer, is
the likely mechanism responsible for the events. This type of instability
requires an inflection point in the background winds near the center of the
vortex roll with a low static stability region capped by an inversion. The
earlier paper argued that the conditions required to support the instability
are common in the altitude range where the features are found. In this paper,
we use data from the University of Illinois sodium lidar that was located at
the Starfire Optical Range near Albuquerque, New Mexico, and from the
Maui/MALT Lidar Facility in Hawaii and present several cases that are used to
examine the behavior of the inflection point in detail as a function of time
during the evolution of the overturning event. In addition, we examine the
background static stability conditions using the temperature data from the
lidar. |
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