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| Titel |
Intensive radiosonde observations of the diurnal tide and planetary waves in the lower atmosphere over Yichang (111°18' E, 30°42' N), China |
| VerfasserIn |
C. M. Huang, S. D. Zhang, F. Yi |
| 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 ; 27, no. 3 ; Nr. 27, no. 3 (2009-03-04), S.1079-1095 |
| Datensatznummer |
250016441
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| Publikation (Nr.) |
 copernicus.org/angeo-27-1079-2009.pdf |
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| Zusammenfassung |
| The characteristics of diurnal tide and planetary waves
(PWs) in the troposphere and lower stratosphere (TLS) over Yichang
(111°18' E, 30°42' N) were studied by using the data from intensive
radiosonde observations in August 2006 (summer month) and January 2007
(winter month) on an eight-times-daily basis. The radiosonde observations of
the diurnal tide and PWs in the TLS in the mid-latitudes have seldom been
reported. We find that there exists dominant diurnal oscillations in the TLS
over Yichang. The observed diurnal tide consists of significant nonmigrating
components, which may be owning to the local latent heat release. Since the
nonmigrating tides are usually composed of high order modes with smaller
vertical wavelengths, which are prone to dissipation in comparison with
the low order modes, the observational tidal amplitudes decrease sharply at
several heights. Some evident discrepancies between the observations and the
GSWM-02 are found, which may result mainly from the inaccurate prediction of
the nonmigrating tidal components by the GSWM-02. And, due to the evident
seasonal differences of the water vapor mixing ratio disturbance and the
tropospheric jet induced turbulence in winter, the diurnal tides in the
summer and winter months have some different characteristics. Besides the
diurnal tide, obvious quasi 7-day PW (QSDPW) and quasi 10-day PW (QTDPW) are
also recognized from our observations in both the summer and winter months.
The QSDPWs in the troposphere in both the summer and winter months show a
standing wave structure, while the QTDPWs generally exhibit traveling wave
characteristics. Spectral analyses reveal that some waves with periods
around that of the diurnal tide are generated due to the interactions of the
diurnal tide and PWs and the tidal amplitudes are modulated by the PWs,
indicating the extensive coupling between the diurnal tide and PWs.
Moreover, our observations manifest that the PWs can exert great impacts on
the tropospheric jet in winter and the tropopause in both the summer and
winter months. |
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