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| Titel |
Particle tracking and mean residence time in barchan dunes |
| VerfasserIn |
Deguo Zhang, Clement Narteau, Olivier Rozier |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077480
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| Zusammenfassung |
| We analyze sediment particles motions in steady-state barchan dunes by tracking individual
cells of a 3-D cellular automaton dune model. The overall sediment flux may be decomposed
into advective and dispersive fluxes to estimate the relative contribution of the underlying
physical processes to the barchan dune shape. The net lateral sediment transport from the
center to the horns indicates that dispersion on the stoss slope is more efficient
than avalanches on the lee slope. The combined effect of these two antagonistic
dispersive processes restricts the lateral mixing of sediment particles in the central
region of barchan dunes. Then, for different flow strength and dune size, we find
that the mean residence time of sediment particles in barchan dunes is equal to the
surface of the central longitudinal dune slices divided by the input sand flux. We
infer that this central slice contains most of the relevant information about barchan
dune morphodynamics. Finally, we initiate a discussion about sediment transport
and memory in presence of bedforms using the advantages of the particle tracking
technique. |
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