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| Titel |
Influence of tides and gravity waves on layering processes in the polar summer mesopause region |
| VerfasserIn |
P. Hoffmann, M. Rapp, J. Fiedler, R. Latteck |
| 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 ; 26, no. 12 ; Nr. 26, no. 12 (2008-12-09), S.4013-4022 |
| Datensatznummer |
250016327
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| Publikation (Nr.) |
 copernicus.org/angeo-26-4013-2008.pdf |
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| Zusammenfassung |
| Polar Mesosphere Summer Echoes (PMSE) have been studied at Andenes
(69° N, 16° E), Norway, using VHF radar observations
since 1994. One remarkable feature of these observations is the
fact that {during 50% of the time,} the radar echoes occur in the
form of two or more distinct layers. In the case of multiple PMSE
layers, statistical analysis shows that the lower layer occurs at
a mean height of ~83.4 km, which is almost identical to the
mean height of noctilucent clouds (NLC) derived from observation
with the ALOMAR Rayleigh/Mie/Raman lidar at the same site. To
investigate the layering processes microphysical model simulations
under the influence of tidal and gravity waves were performed. In
the presence of long period gravity waves, these model
investigations predict an enhanced formation of multiple PMSE
layer structures, where the lower layer is a consequence of the
occurrence of the largest particles at the bottom of the ice
cloud. This explains the coincidence of the lowermost PMSE layers
and NLC. During periods with enhanced amplitudes of the
semidiurnal tide, the observed NLC and PMSE show pronounced tidal
structures comparable to the results of corresponding
microphysical simulations. At periods with short period gravity
waves there is a tendency for a decreasing occurrence of NLC and
for variable weak PMSE structures. |
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