现场证据表明沙丘的表面波引起的不稳定性
Hicham Elbelrhiti1, Philippe Claudin, Bruno Andreotti
1Laboratoire de Physique et Mécanique des Milieux Hétérogènes (LPMMH), UMR CNRS 7636, 10 rue Vauquelin 75005 Paris, France.
Nature
|September 30, 2005
概括
巴尔坎沙丘是不稳定的,与以前的信念相反. 碰撞和风的转移会产生波浪,破坏沙丘角,形成新的小沙丘,并控制沙丘场的模式.
科学领域:
- 地质形态学 地质形态学
- 太阳系气体的过程
- 沙丘动力学的沙丘动力学
背景情况:
- 沙丘 (半月形沙丘) 的研究传统上侧重于沙子运输和空气流之间的平衡.
- 沙丘演变的长时间尺度掩盖了潜在的动态过程.
研究的目的:
- 为了研究统治barchan沙丘演变的动态过程.
- 挑战barchans作为稳定的孤独波的概念.
主要方法:
- 在摩洛哥撒哈拉地区进行了为期三年的联合实地研究.
- 使用了一个补充模型研究.
主要成果:
- 巴尔坎在根本上是不稳定的,不是稳定的孤独波.
- 沙丘碰撞和风向变化会产生破坏稳定的表面波.
- 表面波比沙丘的传播速度更快,打破了角,创造了新的,更小的barchans.
结论:
- 沙丘碰撞和风的变化导致巴坎的不稳定.
- 波浪传播和角侵蚀是新沙丘形成的关键机制.
- 这个过程调节了沙丘大小的选择和模式的发展,防止沙丘场的凝聚.
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