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| Titel |
Consistency between Fourier transform and small-volume few-wave decomposition for spectral and spatial variability of gravity waves above a typhoon |
| VerfasserIn |
C. I. Lehmann, Y.-H. Kim, P. Preusse, H.-Y. Chun, M. Ern, S.-Y. Kim |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 5, no. 7 ; Nr. 5, no. 7 (2012-07-17), S.1637-1651 |
| Datensatznummer |
250003005
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| Publikation (Nr.) |
 copernicus.org/amt-5-1637-2012.pdf |
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| Zusammenfassung |
| Convective gravity wave (GW) sources are spatially localized and emit at the
same time waves with a wide spectrum of phase speeds. Any wave analysis
therefore compromises between spectral and spatial resolution. Future
satellite borne limb imagers will for a first time provide real 3-D volumes of
observations. These volumes will be however limited which will impose further
constraints on the analysis technique. In this study a three dimensional
few-wave approach fitting sinusoidal waves to limited 3-D volumes is
introduced. The method is applied to simulated GWs above typhoon Ewiniar and
GW momentum flux is estimated from temperature fluctuations. Phase speed
spectra as well as average profiles of positive, negative and net momentum
fluxes are compared to momentum flux estimated by Fourier transform as well
as spatial averaging of wind fluctuations. The results agree within
10–20%. The few-wave method can also reveal the spatial orientation of
the GWs with respect to the source. The relevance of the results for
different types of measurements as well as its applicability to model data is
discussed. |
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