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| Titel |
Summer planetary-scale oscillations: aura MLS temperature compared with ground-based radar wind |
| VerfasserIn |
C. E. Meek, A. H. Manson |
| 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. 4 ; Nr. 27, no. 4 (2009-04-09), S.1763-1774 |
| Datensatznummer |
250016498
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| Publikation (Nr.) |
 copernicus.org/angeo-27-1763-2009.pdf |
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| Zusammenfassung |
| The advent of satellite based sampling brings
with it the opportunity to examine virtually any part of the
globe.
Aura MLS mesospheric temperature data are analysed in a
wavelet format for easy identification of possible planetary waves (PW)
and aliases masquerading as PW. A calendar year, 2005, of eastward,
stationary, and westward waves at a selected latitude is shown in
separate panels for wave number range −3 to +3 for period range
8 h to 30 days (d). Such a wavelet analysis is made possible by Aura's
continuous sampling at all latitudes 82° S–82° N.
The data presentation is
suitable for examination of years of data. However
this paper focuses on the striking feature of a "dish-shaped" upper limit
to periods near 2 d in mid-summer, with
longer periods appearing towards spring and fall, a feature also commonly
seen in radar winds.
The most probable cause is suggested to be
filtering by the summer jet at 70–80 km, the latter being available
from ground based medium frequency radar (MFR). Classically, the phase
velocity of a wave must be greater than that of the jet in order to
propagate through it.
As an attempt to directly relate satellite and ground based sampling,
a PW event of period 8d and wave number 2, which appears
to be the original rather than an alias, is compared with ground based
radar wind data.
An appendix discusses characteristics of satellite data aliases with
regard to their periods and amplitudes. |
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