Departmental Papers (EES)

Document Type

Journal Article

Date of this Version

10-2010

Publication Source

Geophysical Research Letters

Volume

37

Issue

19

Start Page

L19402

DOI

10.1029/2010GL044957

Abstract

Many dune fields exhibit a downwind transition from forward-pointing barchan dunes to stabilized, backward-pointing parabolic dunes, accompanied by an increase in vegetation. A recent model predicts this pattern transition occurs when dune surface erosion/deposition rates decrease below a threshold of half the vegetation growth rate. We provide a direct test using a unique data set of repeat topographic surveys across White Sands Dune Field and find strong quantitative support for the model threshold. We also show the threshold hypothesis applied to a barchan dune results naturally in its curvature inversion, as the point of threshold crossing progresses from the horns to the crest. This simple, general threshold framework can be an extremely useful tool for predicting the response of dune landscapes to changes in wind speed, sediment supply, or vegetation growth rate. Near the threshold, a small environmental change could result in a drastic change in dune pattern and activity.

Copyright/Permission Statement

Copyright © 2010 by the American Geophysical Union.

Keywords

aeolian, pattern transition, parabolic dune, vegetation feedback, threshold

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Date Posted: 11 November 2016

This document has been peer reviewed.