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| Titel |
Comparative studies of methods of obtaining AGW's propagation properties |
| VerfasserIn |
H. Y. Lue, F. S. Kuo |
| 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 ; 30, no. 3 ; Nr. 30, no. 3 (2012-03-19), S.557-570 |
| Datensatznummer |
250017201
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| Publikation (Nr.) |
 copernicus.org/angeo-30-557-2012.pdf |
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| Zusammenfassung |
| Three among the existing methods of obtaining the properties (intrinsic
period, wavelength, propagation direction) of atmospheric gravity waves
(AGWs) were compared and studied by numerical method to simulate radar data.
Three-dimensional fluctuation velocity satisfying dispersion equation and
polarization relation of atmospheric gravity wave were generated, then the
numerical data were analysed by these methods to obtain the properties of
waves. We found that, hodograph analysis was accurate for a monochromatic
wave in obtaining its wave period and propagation direction, but the analysis
became erratic for the case of multiple waves' superposition. The error was
especially large when data consisted of both upward propagating waves and
downward propagating waves. The hodograph method became meaningful again if all
the component waves propagated in the same direction and the resulting period
was dominantly decided by the lowest frequency wave. Stokes parameters
method would obtain statistically meaningful values of wave period and
azimuth if the spreading of the azimuths among the component waves did not
exceed 90° and the resulting period and azimuth were dominated by
the lowest frequency wave component as well, irrespective of the vertical
sense of propagation. Another method called phase and group velocity tracing
technique was reconfirmed to be meaningful in measuring the characteristic
wave period and vertical group and phase velocities of a wave packet: the
characteristic wave period and vertical wavelength was dominated by the wave
with the highest frequency among the component waves in the wave packet.
Based on these numerical results, a composite procedure of data analysis for
wave propagation was proposed and an example of real data analysis was
presented. |
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