EGU22-2079
https://doi.org/10.5194/egusphere-egu22-2079
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Direct validation of dune instability theory

Clément Narteau1, Ping Lü2, Philippe Claudin3, Zhibao Dong2, Sébastien Rodriguez1, Zhishan An4, Laura Fernandez-Cascales1, Cyril Gadal1, and Sylvain Courrech du Pont5
Clément Narteau et al.
  • 1Université de Paris, Institut de physique du Globe de Paris, CNRS, F-75005 Paris, France (narteau@ipgp.fr)
  • 2School of Geography and Tourism, Shaanxi Normal University, 620 Chang'an West Avenue, Xi'an, Shaanxi 710119, China
  • 3Physique et Mécanique des Milieux Hétérogènes, CNRS, ESPCI, PSL Research Univ, Sorbonne Univ, Université de Paris, 10 rue Vauquelin, 75005 Paris, France
  • 4Northwest Institute of Eco-Environment and Resources, Donggang West Road 320, Lanzhou, Gansu Province 730000, China
  • 5Laboratoire Matière et Système Complexes, Université de Paris, CNRS, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France

We designed a landscape-scale experiment at the edge of the Gobi desert, China, to quantify the development of incipient dunes under the natural action of winds (Lü et al., 2021). High-resolution topographic data documenting 42 months of bedform dynamics are examined to provide a spectral analysis of dune pattern formation. We identified two successive phases in the process of dune growth, from the initial flat sand bed to a meter-high periodic pattern. We focus on the initial phase, when the linear regime of dune instability applies, and measure the growth rate of dunes of different wavelengths. We identify the existence of a maximum growth rate, which readily explains the mechanism by which dunes select their size, leading to the prevalence of a 15 m-wavelength pattern. We quantitatively compare our experimental results to the prediction of the dune instability theory using transport and flow parameters independently measured in the field. The remarkable agreement between theory and observations demonstrates that the linear regime of dune growth is permanently expressed on low-amplitude bed topography, before larger regular patterns and slip faces eventually emerge. Our experiment underpin existing theoretical models for the early development of eolian dunes, which can now be used to provide reliable insights into atmospheric and surface processes on Earth and other planetary bodies.

 

Bibliography:

Lü P., C. Narteau, Z. Dong, P. Claudin, S. Rodriguez, Z. An, L. Fernandez-Cascales, C. Gadal, S. Courrech du Pont, Direct validation of dune instability theory, Proceedings of the National Academy of Sciences, 118, 17 (2021).

How to cite: Narteau, C., Lü, P., Claudin, P., Dong, Z., Rodriguez, S., An, Z., Fernandez-Cascales, L., Gadal, C., and Courrech du Pont, S.: Direct validation of dune instability theory, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2079, https://doi.org/10.5194/egusphere-egu22-2079, 2022.