Elongation and stability of a linear dune

Abstract

Compared to barchan dunes, the morphodynamics of linear dunes that elongate on a non-erodible bed is barely investigated by means of laboratory experiments or numerical simulations. Using a cellular automaton model, we study the elongation of a solitary linear dune from a sand source and show that it can reach a steady state. This steady state is analyzed to understand the physical processes at work along the dune. Crest reversals together with avalanche processes control the shape of transverse sections. Dune width and height decrease almost linearly with distance downstream until the minimum size for dunes. This is associated with a constant sand loss along the dune, which eventually compensates for the sediment influx and sets the dune length. This sand budget is discussed to distinguish an elongating linear dune from a barchan dune and to explain the complexity of linear dune fields in nature.

arXiv comment16 pages, 4 figures

References in corpus (5)

• Corridors of barchan dunes: stability and size selection
• Barchan dune corridors: field characterization and investigation of control parameters
• Transverse instability of dunes
• Incipient bedforms in a bidirectional wind regime
• Out of equilibrium stationary states, percolation, and sub-critical instabilities in a fully non conservative system

Cited by in corpus (4)

• Local Wind Regime Induced by Giant Linear Dunes: Comparison of ERA5-Land Reanalysis with Surface Measurements
• Coexistence of two dune growth mechanisms in a landscape-scale experiment
• Field evidence for the initiation of isolated aeolian sand patches
• From lab to landscape-scale experiments for the morphodynamics of sand dunes