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Titel |
Multimodal structure of baroclinic tides in the South China Sea |
VerfasserIn |
V. Vlasenko, N. Stashchuk, C. Guo, X. Chen |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1023-5809
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Digitales Dokument |
URL |
Erschienen |
In: Nonlinear Processes in Geophysics ; 17, no. 5 ; Nr. 17, no. 5 (2010-10-07), S.529-543 |
Datensatznummer |
250013730
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Publikation (Nr.) |
copernicus.org/npg-17-529-2010.pdf |
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Zusammenfassung |
The modelling of baroclinic tides generated in the northern South China Sea
is studied using a fully-nonlinear non-hydrostatic numerical model. The focus
of the modelling efforts was on the vertical structure of internal waves in the
vicinity of the Luzon Strait.
The barotropic tidal flow interacting with a two-ridge bottom topography in
the area of the Luzon Strait produces a complex baroclinic tidal signal. A
multimodal baroclinic bore with counter-phase displacement of isopycnals
generated over the ridges and propagating westward disintegrates into a
series of large-amplitude solitary internal waves. The leading first-mode
solitary wave of depression is followed by a second mode solitary wave
coupled with a packet of short-scale internal waves riding it. Scrutiny of
the characteristics of the both wave forms, i.e. the carrier second-mode
solitary wave and the packet of short waves, revealed that the short-scale
waves are basically concentrated in the upper 500 m layer and attenuate
exponentially below it. The short waves exist only thanks to a specific
structure of horizontal velocity produced by the second-mode solitary wave.
Having equal phase speeds and propagating together for a long distance, this
coupled system produces quite a remarkable signal at the free surface, which
can be detected by means of remote sensing technique.
It was found in a series of sensitivity experiments that the eastern ridge is
responsible for the generation of progressive first-mode tidal waves
disintegrated into packets of first-mode ISWs. The western ridge produces
quite a strong higher-mode signal. The waves generated over the eastern and
western ridges interfere in the near-field, and their nonlinear superposition
enhances the multimodal signal in the whole domain. |
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