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| Titel |
Frequency domain interferometry mode observations of PMSE using the EISCAT VHF radar |
| VerfasserIn |
P. B. Chilson, S. Kirkwood  , I. Häggström |
| 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 ; 18, no. 12 ; Nr. 18, no. 12, S.1599-1612 |
| Datensatznummer |
250014104
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| Publikation (Nr.) |
 copernicus.org/angeo-18-1599-2000.pdf |
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| Zusammenfassung |
During the summer of 1997 investigations into
the nature of polar mesosphere summer echoes (PMSE) were conducted using the
European incoherent scatter (EISCAT) VHF radar in Norway. The radar was operated
in a frequency domain interferometry (FDI) mode over a period of two weeks to
study the frequency coherence of the returned radar signals. The operating
frequencies of the radar were 224.0 and 224.6 MHz. We present the first results
from the experiment by discussing two 4-h intervals of data collected over two
consecutive nights. During the first of the two days an enhancement of the FDI
coherence, which indicates the presence of distinct scattering layers, was found
to follow the lower boundary of the PMSE. Indeed, it is not unusual to observe
that the coherence values are peaked around the heights corresponding to both
the lower- and upper-most boundaries of the PMSE layer and sublayers. A Kelvin-Helmholtz
mechanism is offered as one possible explanation for the layering structure.
Additionally, our analysis using range-time-pseudocolor plots of signal-to-noise
ratios, spectrograms of Doppler velocity, and estimates of the positions of
individual scattering layers is shown to be consistent with the proposition that
upwardly propagating gravity waves can become steepened near the mesopause.
Key words: Ionosphere (polar ionosphere) · Meteorology
and Atmospheric Dynamics (middle atmosphere dynamics) · Radio Science (Interferometry) |
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