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Titel |
Wavelet analysis of turbulence in cirrus clouds |
VerfasserIn |
S. A. Smith, P. R. Jonas |
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 ; 15, no. 11 ; Nr. 15, no. 11, S.1447-1456 |
Datensatznummer |
250013008
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Publikation (Nr.) |
copernicus.org/angeo-15-1447-1997.pdf |
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Zusammenfassung |
Two flights of the UK Meteorological Office's
Hercules aircraft through daytime frontal cirrus around Scotland have been
analysed using wavelet analysis on the vertical velocity time-series from the
horizontal runs. It is shown that wavelet analysis is a useful tool for
analysing the turbulence data in cirrus clouds. It finds the largest scales
involved in producing turbulence, as does Fourier analysis, such as the 2-km
spectral peaks corresponding to convective activity during flight A283. Wavelet
spectra have the added advantage that the position is shown, and so they
identify smaller-scale, highly localised processes such as the production of
turbulent kinetic energy by the breaking of Kelvin-Helmholtz waves due to the
vertical shear in the horizontal wind. These may be lost in Fourier spectra
obtained for long time-series, though they contribute something to the average
spectral density at the appropriate scale. The main disadvantage of this
technique is that only octave frequency bands are resolved. |
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