Coexistence of Two Dune Growth Mechanisms in a Landscape‐Scale Experiment

作者：Ping Lü, C. Narteau, Zhibao Dong, Philippe Claudin, S. Rodríguez, Zhishan An, Cyril Gadal, Sylvain Courrech du Pont · 发表于：Geophysical Research Letters · 年份：2022 · DOI：10.1029/2021gl097636 · 被引用次数：16 · 研究领域：Aeolian processes and effects、Tree Root and Stability Studies、Soil erosion and sediment transport

Abstract In landscape‐scale experiments at the edge of the Gobi desert, we show that various dune types develop simultaneously under natural wind conditions. Using 4 years of high‐resolution topographic data, we demonstrate that, depending on sand availability, the same wind regime can lead to two different dune orientations, which reflect two independent dune growth mechanisms. As periodic oblique dunes emerge from a sand bed and develop to 2 m in height, we analyze defect dynamics that drive the non‐linear phase of pattern coarsening. Starting from conical sand heaps deposited on gravels, we observe the transition from dome to barchan and asymmetric barchan shapes. We identify a minimum size for arm elongation and evaluate the contribution of wind reversals to its longitudinal alignment. These experimental field observations support existing theoretical models of dune dynamics boosting confidence in their applicability for quantitative predictions of dune evolution under various wind regimes and bed conditions.