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| Titel |
Occurrence of polar mesosphere summer echoes at very high latitudes |
| VerfasserIn |
M. Zecha, J. Röttger |
| 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. 3 ; Nr. 27, no. 3 (2009-03-30), S.1331-1342 |
| Datensatznummer |
250016459
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| Publikation (Nr.) |
 copernicus.org/angeo-27-1331-2009.pdf |
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| Zusammenfassung |
| Observations of polar mesosphere summer echoes (PMSE) have been carried out
during the summer periodes 1999–2001 and 2003–2004 at the very high latitude of
78° N using the SOUSY Svalbard Radar (53.5 MHz) at Longyearbyen.
Although the measurements could not be done continuously in these seasons,
PMSE have been detected over more than 6600 h of 9300 h of observation
time overall. Using this data base, particular PMSE occurrence characteristics
have been determined. PMSE at Svalbard appear from the middle of May to the end of
August with an almost permanent total occurrence in June and July. Diurnal
variations are observable in the height-depend occurrence rates and in PMSE
thickness, they show a maximum around 09:00–10:00 UTC and a minimum around
21:00–22:00 UTC. PMSE occur nearly exclusively between a height of 80 km and 92 km with
a maximum near 85 km. However, PMSE appear not simultaneously over the entire
height range, the mean vertical PMSE extension is around 4–6 km in June and
July. Furthermore, typically PMSE are separated into several layers, and only
30% of all PMSE are single layers. The probability of multiple layers is
greater in June and July than at the beginning and the end of the PMSE season
and shows a marked 5-day-variation. The same variation is noticeable in the
seasonal dependence of the PMSE occurrence and the PMSE thickness. We finally
discuss potential geophysical processes to explain our observational results. |
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