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| Titel |
The 16-day planetary wave in the mesosphere and lower thermosphere |
| VerfasserIn |
N. J. Mitchell, H. R. Middleton, A. G. Beard, P. J. S. Williams, H. G. Muller |
| 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 ; 17, no. 11 ; Nr. 17, no. 11, S.1447-1456 |
| Datensatznummer |
250013837
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| Publikation (Nr.) |
 copernicus.org/angeo-17-1447-1999.pdf |
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| Zusammenfassung |
A meteor radar located at Sheffield in the UK
has been used to measure wind oscillations with periods in the range 10–28 days
in the mesosphere/lower-thermosphere region at 53.5°N, 3.9°W from January 1990
to August 1994. The data reveal a motion field in which wave activity occurs
over a range of frequencies and in episodes generally lasting for less than two
months. A seasonal cycle is apparent in which the largest observed amplitudes
are as high as 14 ms–1 and are observed from January to mid-April. A
minimum in activity occurs in late June to early July. A second, smaller,
maximum follows in late summer/autumn where amplitudes reach up to 7–10 ms–1.
Considerable interannual variability is apparent but wave activity is observed
in the summers of all the years examined, albeit at very small amplitudes near
mid summer. This behaviour suggests that the equatorial winds in the mesopause
region do not completely prevent inter-hemispheric ducting of the wave from the
winter hemisphere, or that it is generated in situ.
Key words. Meteorology and atmospheric dynamics (middle
atmosphere dynamics; thermospheric dynamics; waves and tides) |
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