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Titel |
Internal waves and temperature fronts on slopes |
VerfasserIn |
S. A. Thorpe, U. Lemmin |
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 ; 17, no. 9 ; Nr. 17, no. 9, S.1227-1234 |
Datensatznummer |
250013815
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Publikation (Nr.) |
copernicus.org/angeo-17-1227-1999.pdf |
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Zusammenfassung |
Time series measurements from an array of
temperature miniloggers in a line at constant depth along the sloping boundary
of a lake are used to describe the `internal surf zone' where internal waves
interact with the sloping boundary. More small positive temperature time
derivatives are recorded than negative, but there are more large negative values
than positive, giving the overall distribution of temperature time derivatives a
small negative skewness. This is consistent with the internal wave dynamics;
fronts form during the up-slope phase of the motion, bringing cold water up the
slope, and the return flow may become unstable, leading to small advecting
billows and weak warm fronts. The data are analysed to detect `events', periods
in which the temperature derivatives exceed a set threshold. The speed and
distance travelled by `events' are described. The motion along the slope may be
a consequence of (a) instabilities advected by the flow (b) internal waves
propagating along-slope or (c) internal waves approaching the slope from oblique
directions. The propagation of several of the observed 'events' can only be
explained by (c), evidence that the internal surf zone has some, but possibly
not all, the characteristics of the conventional 'surface wave' surf zone, with
waves steepening as they approach the slope at oblique angles.
Key words. Oceanography: general (benthic boundary
layers; limnology), Oceanography: physical (internal and inertial waves) |
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