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| Titel |
The 16-day wave in the Arctic and Antarctic mesosphere and lower thermosphere |
| VerfasserIn |
K. A. Day, N. J. Mitchell |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 3 ; Nr. 10, no. 3 (2010-02-11), S.1461-1472 |
| Datensatznummer |
250008056
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| Publikation (Nr.) |
 copernicus.org/acp-10-1461-2010.pdf |
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| Zusammenfassung |
| The 16-day planetary wave in the polar mesosphere and lower thermosphere has
been investigated using meteor radars at Esrange (68° N,
21° E) in the Arctic and Rothera (68° S, 68° W)
in the Antarctic. The measurements span the 10-year interval from October
1999 to July 2009 and the 5-year interval February 2005 to July 2009,
respectively. The height range covered is about 80–100 km. In both polar
regions the wave is seen to occur in intermittent bursts, where wave
amplitudes typically reach a maximum of about 15 m s−1, and
never more than about 20 m s−1. Horizontal wind variance
within a wave-period range of 12 to 20 days is used as a proxy for the
activity of the 16-day wave. Wave activity is strong for 3 to 4 months in
winter, where it is present across the entire height range observed and
monthly wave variance reaches about 65 m2 s−2. Some weak
and intermittent activity is observed throughout the other seasons including
summer. However, there is a high degree of inter-annual variability and in
some individual years wave activity is almost absent. The data are used to
construct a representative climatology for the Arctic and Antarctic. The
seasonal cycle of the 16-day wave is found to be very similar in both polar
regions. The 16-day wave has slightly greater amplitudes in the zonal
component of the winds than in the meridional. Mesospheric temperatures
measured by the radars were used to further investigate the 16-day wave. The
temperatures reveal a clear signature of the 16-day wave. Temperature
amplitudes are generally only a few Kelvin but occasional bursts of up to 10 K
have been observed. Observations of the wave in summer are sometimes
consistent with the suggestion of ducting from the winter hemisphere. |
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