Elongation and Stability of a Linear Dune

Compared to barchan dunes, the morphodynamics of linear dunes that elongate on a nonerodible bed have barely been 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 dune is reached. 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.

[1]  P. Claudin,et al.  Incipient bedforms in a bidirectional wind regime , 2019, Journal of Fluid Mechanics.

[2]  C. Narteau,et al.  Morphodynamics of barchan and dome dunes under variable wind regimes , 2018, Geology.

[3]  C. Narteau,et al.  Unravelling raked linear dunes to explain the coexistence of bedforms in complex dunefields , 2017, Nature Communications.

[4]  E. Bertin,et al.  Out-of-equilibrium stationary states, percolation, and subcritical instabilities in a fully nonconservative system. , 2016, Physical review. E.

[5]  C. Narteau,et al.  Controls on and effects of armoring and vertical sorting in aeolian dune fields: A numerical simulation study , 2016 .

[6]  C. Narteau,et al.  Development and steady states of transverse dunes: A numerical analysis of dune pattern coarsening and giant dunes , 2015 .

[7]  Xin Gao,et al.  Phase diagrams of dune shape and orientation depending on sand availability , 2015, Scientific Reports.

[8]  A. Hayes,et al.  Growth mechanisms and dune orientation on Titan , 2014 .

[9]  C. Narteau,et al.  Two modes for dune orientation , 2014 .

[10]  C. Narteau,et al.  Mean sediment residence time in barchan dunes , 2014 .

[11]  Clément Narteau,et al.  A real‐space cellular automaton laboratory , 2013 .

[12]  G. Grégoire,et al.  Spatial structuring and size selection as collective behaviours in an agent-based model for barchan fields , 2013 .

[13]  P. Claudin,et al.  Modeling emergent large-scale structures of barchan dune fields , 2013 .

[14]  G. Grégoire,et al.  An agent‐based model of dune interactions produces the emergence of patterns in deserts , 2013 .

[15]  D. Lague,et al.  Sand dunes as migrating strings. , 2013, Physical review. E, Statistical, nonlinear, and soft matter physics.

[16]  Clément Narteau,et al.  Morphology and dynamics of star dunes from numerical modelling , 2012 .

[17]  J. S. Andrade,et al.  Transverse instability of dunes. , 2011, Physical review letters.

[18]  Dan G. Blumberg,et al.  Age, origin and climatic controls on vegetated linear dunes in the northwestern Negev Desert (Israel) , 2011 .

[19]  Clément Narteau,et al.  Morphodynamics of barchan and transverse dunes using a cellular automaton model , 2010 .

[20]  S. Douady,et al.  Formation and stability of transverse and longitudinal sand dunes , 2010 .

[21]  E. Rhodes,et al.  Investigation of the age and migration of reversing dunes in Antarctica using GPR and OSL, with implications for GPR on Mars , 2010 .

[22]  H. Herrmann,et al.  Dune formation under bimodal winds , 2009, Proceedings of the National Academy of Sciences.

[23]  D. Rubin,et al.  Multiple origins of linear dunes on Earth and Titan , 2009 .

[24]  Clément Narteau,et al.  Setting the length and time scales of a cellular automaton dune model from the analysis of superimposed bed forms , 2008 .

[25]  D. Rubin,et al.  A second look at western Sinai seif dunes and their lateral migration , 2008 .

[26]  Bruno Andreotti,et al.  Barchan dune corridors: Field characterization and investigation of control parameters , 2006, cond-mat/0609120.

[27]  David S. G. Thomas,et al.  Late Quaternary linear dune accumulation and chronostratigraphy of the southwestern Kalahari: implications for aeolian palaeoclimatic reconstructions and predictions of future dynamics , 2007 .

[28]  Nicholas Lancaster,et al.  Age and dynamics of linear dunes in the Namib Desert , 2007 .

[29]  S. Douady,et al.  Collision of barchan dunes as a mechanism of size regulation , 2005 .

[30]  P. Claudin,et al.  Field evidence for surface-wave-induced instability of sand dunes , 2005, Nature.

[31]  K. H. Andersen,et al.  Corridors of barchan dunes: Stability and size selection. , 2003, Physical review. E, Statistical, nonlinear, and soft matter physics.

[32]  N. Lancaster,et al.  The sedimentary structure of linear sand dunes , 2000, Nature.

[33]  N. Lancaster.  FIELD STUDIES OF SAND PATCH INITIATION PROCESSES ON THE NORTHERN MARGIN OF THE NAMIB SAND SEA , 1996 .

[34]  H. Tsoar.  Linear dunes - forms and formation , 1989 .

[35]  I. Livingstone.  Monitoring surface change on a Namib linear dune , 1989 .

[36]  N. Lancaster.  Linear dunes , 1982 .

[37]  H. Tsoar.  Internal Structure and Surface Geometry of Longitudinal (Seif) Dunes , 1982 .

[38]  M. Mainguet,et al.  L'erg de Fachi-Bilma, Tchad-Niger : contribution à la connaissance de la dynamique des ergs et des dunes des zones arides chaudes , 1978 .