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| Titel |
Long solitary internal waves in stable stratifications |
| VerfasserIn |
W. B. Zimmerman, J. M. Rees |
| 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 ; 11, no. 2 ; Nr. 11, no. 2 (2004-04-14), S.165-180 |
| Datensatznummer |
250009129
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| Publikation (Nr.) |
 copernicus.org/npg-11-165-2004.pdf |
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| Zusammenfassung |
| Observations of internal solitary waves over an antarctic ice shelf
(Rees and Rottman, 1994) demonstrate that
even large amplitude disturbances have wavelengths that are bounded by
simple heuristic arguments following from the Scorer parameter based on
linear theory for wave trapping. Classical weak nonlinear theories that
have been applied to stable stratifications all begin with perturbations
of simple long waves, with corrections for weak nonlinearity and dispersion
resulting in nonlinear wave equations (Korteweg-deVries (KdV) or
Benjamin-Davis-Ono) that admit localized propagating solutions. It is shown
that these
theories are apparently inappropriate when the Scorer parameter, which gives the
lowest wavenumber that does not radiate vertically, is positive. In this
paper, a new nonlinear evolution equation is derived for an arbitrary wave packet
thus including one bounded below by the
Scorer parameter. The new theory shows that solitary internal waves excited in
high Richardson number waveguides are predicted to have a
halfwidth inversely proportional to the Scorer parameter, in agreement
with atmospheric observations. A localized analytic solution for the new
wave equation is demonstrated, and its soliton-like properties are demonstrated
by numerical simulation. |
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