Spatial and temporal development of incipient dunes

Abstract

In zones of loose sand, wind-blown sand dunes emerge due the linear instability of a flat sedimentary bed. This instability has been studied in experiments and numerical models but rarely in the field, due to the large time and length scales involved. We examine dune formation at the upwind margin of the White Sands Dune Field in New Mexico (USA), using 4 years of lidar topographic data to follow the spatial and temporal development of incipient dunes. Data quantify dune wavelength, growth rate, and propagation velocity and also the characteristic length scale associated with the growth process. We show that all these measurements are in quantitative agreement with predictions from linear stability analysis. This validation makes it possible to use the theory to reliably interpret dune-pattern characteristics and provide quantitative constraints on associated wind regimes and sediment properties, where direct local measurements are not available or feasible.

15 pages, 3 figures

References in corpus (11)

• A scaling law for aeolian dunes on Mars, Venus, Earth, and for subaqueous ripples
• Minimal Model for Sand Dunes
• Minimal model for aeolian sand dunes
• Selection of dune shapes and velocities. Part 2: A two-dimensional modelling
• A unified model of ripples and dunes in water and planetary environments
• Collision dynamics of two barchan dunes simulated by a simple model
• Flux saturation length of sediment transport
• Giant ripples on comet 67P/Churyumov-Gerasimenko sculpted by sunset thermal wind
• Field evidence for the upwind velocity shift at the crest of low dunes
• Incipient bedforms in a bidirectional wind regime
• Periodicity in fields of elongating dunes

Cited by in corpus (6)

• Direct validation of dune instability theory
• Dune initiation in a bimodal wind regime
• 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
• Modeling the dynamics of aeolian meter-scale bedforms induced by bed heterogeneities