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Titel |
How kilometric sandy shoreline undulations correlate with wave and morphology characteristics: preliminary analysis on the Atlantic coast of Africa |
VerfasserIn |
D. Idier, A. Falques |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7340
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Digitales Dokument |
URL |
Erschienen |
In: Proceedings of river, coastal and estuarine morphodynamics ; Nr. 39 (2014-04-01), S.55-60 |
Datensatznummer |
250121304
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Publikation (Nr.) |
copernicus.org/adgeo-39-55-2014.pdf |
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Zusammenfassung |
Sandy coasts are characterized by a number of rhythmic patterns like,
amongst others, shoreline undulations or sandwaves at a kilometric scale.
One hypothesis for their formation is that high angle waves (large incidence
angle with respect to shore normal) could induce an instability of the
shoreline (Ashton et al., 2001). More recently, a scaling for their
wavelength has also been proposed (van den Berg et al., 2014). The
existing studies rely mainly on modelling but quantitative field tests are
lacking. We aim at investigating how both the formation hypothesis of these
shoreline undulations and the theoretical scaling do fit with nature at a
global scale. The first step, which is the goal of this paper, is to set up
the methodology by analyzing the Atlantic African coast as test site. First,
based on global databases, shoreline wavelength LS, wave characteristics
(obliquity θW and wavelength
λW) and mean shoreface slope β are determined. Then
the wave obliquity is confronted with the presence of shoreline
undulations. Finally the values of the ratio β LS / λW are
estimated and discussed in comparison with the estimate of
van den Berg et al. (2014). It is found that the correlation between
shoreline sandwave occurrence and wave obliquity is
very good, allowing the identification of 5 new potential unstable
shoreline stretches, whereas the results on the scaling
are not conclusive and deserve further investigations. |
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