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| Titel |
Quantification of waves in lidar observations of noctilucent clouds at scales from seconds to minutes |
| VerfasserIn |
N. Kaifler, G. Baumgarten, J. Fiedler, F.-J. Lübken |
| 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 ; 13, no. 23 ; Nr. 13, no. 23 (2013-12-04), S.11757-11768 |
| Datensatznummer |
250085854
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| Publikation (Nr.) |
 copernicus.org/acp-13-11757-2013.pdf |
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| Zusammenfassung |
| We present small-scale structures and waves observed in noctilucent
clouds (NLC) by lidar at an unprecedented temporal resolution of
30 s or less. The measurements were taken with the
Rayleigh/Mie/Raman lidar at the ALOMAR observatory in northern
Norway (69° N) in the years 2008–2011. We find multiple layer
NLC in 7.9% of the time for a brightness threshold of
δ β = 12 × 10−10 m−1 sr−1. In comparison
to 10 min averaged data, the 30 s dataset shows
considerably more structure. For limited periods, quasi-monochromatic
waves in NLC altitude variations are common, in accord with
ground-based NLC imagery. For the combined dataset, on the other hand,
we do not find preferred periods but rather significant periods at all
timescales observed (1 min to 1 h). Typical wave
amplitudes in the layer vertical displacements are 0.2 km with
maximum amplitudes up to 2.3 km. Average spectral slopes of
temporal altitude and brightness variations are −2.01 ± 0.25 for
centroid altitude, −1.41 ± 0.24 for peak brightness and
−1.73 ± 0.25 for integrated brightness. Evaluating a new single-pulse
detection system, we observe altitude variations of 70 s
period and spectral slopes down to a scale of 10 s. We
evaluate the suitability of NLC parameters as tracers for gravity
waves. |
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