 |
| Titel |
Armoring and vertical sorting in aeolian dune fields |
| VerfasserIn |
Xin Gao, Clement Narteau, Olivier Rozier |
| Konferenz |
EGU General Assembly 2016
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250126370
|
| Publikation (Nr.) |
 EGU/EGU2016-6079.pdf |
|
|
|
|
|
| Zusammenfassung |
| Unlike ripples, there are only few numerical studies on grain-size segregation at the scale of
dunes in aeolian environments. Here we use a cellular automaton model to analyze vertical
sorting in granular mixtures under steady unidirectional flow conditions. We investigate the
feedbacks between dune growth and the segregation mechanisms by varying the size of
coarse grains and their proportion within the bed. We systematically observe the development
of a horizontal layer of coarse grains at the top of which sorted bed forms may grow by
amalgamation. The formation of such an armor layer controls the overall sediment
transport and availability. The emergence of dunes and the transition from barchan to
transverse dune fields depend only on the grain size distribution of the initial sediment
layer. As confirmed by observation, this result indicates that armor layers should be
present in most arid deserts, where they are likely to control dune morphodynamics. |
|
|
|
|
|
|