Reference work entry
Modified wedge dune extended longitudinally in the resultant transport direction.
Drop dunes form in areas where sand supply is low and subject to a bimodal wind regime where the directions of the winds differ by >120° (Parteli and Herrmann 2007; Parteli et al. 2009a; Reffet et al. 2010). It originates from a wedge dune whose downwind tail elongates, leading to a longitudinal dune (Parteli et al. 2009a; Fig. 1).
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