A process-based hypothesis for the barchan–parabolic transformation and implications for dune activity modelling

Auteur(s) et Affiliation(s)



Description :
The process is described in terms of variations in the stabilization of wind-parallel cross-sectional dune slices. The AA. hypothesize that stabilization of individual dune slices is the predictable result of feedbacks initiated from colonization of vegetation on the slipface, which can only occur when slipface deposition rates are less than the deposition tolerance of vegetation. Under a constant vegetation growth regime the transformation of a barchan dune into a parabolic dune is a geometric response to spanwise gradients in deposition rates. Initial vegetation colonization of barchan horns causes shear between the anchored sides and the advancing centre of the dune, which rotates the planform brinkline angle from concave- to convex-downwind. This reduces slipface deposition rate and allows vegetation to expand inward from the arms to the dune centre. The planform inversion of bare barchans dunes into vegetated parabolic dunes ultimately leads to complete stabilization.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2012, vol. 37, n°. 13, p. 1456-1462, nombre de pages : 7, Références bibliographiques : 1 p.

Date :
2012

Editeur :
Pays édition : Royaume-Uni, Chichester, Wiley