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| Titel |
Analysis of gravity-waves produced by intense tropical cyclones |
| VerfasserIn |
F. Chane Ming, Z. Chen, F. Roux |
| 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 ; 28, no. 2 ; Nr. 28, no. 2 (2010-02-15), S.531-547 |
| Datensatznummer |
250016782
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| Publikation (Nr.) |
 copernicus.org/angeo-28-531-2010.pdf |
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| Zusammenfassung |
| Conventional and wavelet methods are combined to characterize gravity-waves
(GWs) produced by two intense tropical cyclones (TCs) in the upper
troposphere and lower stratosphere (UT/LS) from GPS winsonde data. Analyses
reveal large contribution of GWs induced by TCs to wave energy densities in
the UT/LS. An increase in total energy density of about 30% of the
climatological energy density in austral summer was estimated in the LS
above Tromelin during TC Dina. Four distinct periods in GW activity in
relation with TC Faxai stages is observed in the UT. Globally, GWs have
periods of 6 h–2.5 days, vertical wavelenghts of 1–3 km and horizontal
wavelengths <1000 km in the UT during the evolution of TCs. Horizontal
wavelengths are longer in the LS and about 2200 km during TCs. Convective
activity over the basin and GW energy density were modulated by mixed
equatorial waves of 3–4 days, 6–8 days and 10–13 days confirmed by
Hövmöller diagram, Fourier and wavelet analyses of OLR data.
Moreover, location of GW sources is below the tropopause height when TCs are
intense otherwise varies at lower tropospheric heights depending on the
strength of convection. Finally, the maximum surface wind speeds of TCs Dina
and Faxai can be linearly estimated with total energy densities. |
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