Field Evidence for the Initiation of Isolated Aeolian Sand Patches
Field Evidence for the Initiation of Isolated Aeolian Sand Patches
复制标题
DOI：
10.1029/2022gl101553
复制
发表时间：
2023-01
影响因子：
5.2
通讯作者：
P. Delorme;J. Nield;G. Wiggs;M. Baddock;N. Bristow;J. Best;K. Christensen;P. Claudin
中科院分区：
文献类型：
--
作者：
P. Delorme;J. Nield;G. Wiggs;M. Baddock;N. Bristow;J. Best;K. Christensen;P. Claudin
沙斑是早期原沙丘的前兆之一，广泛存在于沙漠和海岸风沙环境中。在这里，我们展示了一种机制的现场证据，可以解释在不可侵蚀的表面上形成沙斑的原因，例如沙漠砾石和潮湿的海滩。在不可侵蚀表面和可侵蚀表面之间的边界处观察到的与跃变层高度和可变输运规律直接相关的输沙动力学变化导致可侵蚀表面上的泥沙沉积。这解释了沙地斑块是如何在沙丘理论的线性稳定性不适用的有限沙地可用性的表面上形成的。这种新的机制是支持现场观察，证据在不同的表面和原位补丁形成，导致修改的运输动力学在表面边界的运输速率的变化。
Sand patches are one of the precursors to early stage protodunes and occur widely in both desert and coastal aeolian environments. Here we show field evidence of a mechanism to explain the initiation of sand patches on non‐erodible surfaces, such as desert gravels and moist beaches. Changes in sand transport dynamics, directly associated with the height of the saltation layer and variable transport law, observed at the boundary between non‐erodible and erodible surfaces lead to sand deposition on the erodible surface. This explains how sand patches can form on surfaces with limited sand availability where linear stability of dune theory does not apply. This new mechanism is supported by field observations that evidence both the change in transport rate over different surfaces and in situ patch formation that leads to modification of transport dynamics at the surface boundary.