论文标题
初期沙丘的空间和时间发展
Spatial and temporal development of incipient dunes
论文作者
论文摘要
在松散的沙子区域中，由于平坦的沉积床线性不稳定性而出现了风吹沙丘。由于涉及的时间和长度尺度，在实验和数值模型中已经研究了这种不稳定。我们使用4年的LiDAR地形数据遵循初期沙丘的空间和时间发展，研究了新墨西哥州（美国）白色沙丘田的前风缘的沙丘形成。数据量化了沙丘波长，生长速率和繁殖速度，以及与生长过程相关的特征长度尺度。我们表明，所有这些测量值与线性稳定性分析的预测符合定量一致。这种验证使使用该理论可靠地解释沙丘 - 模式特征并对相关的风度和沉积物特性提供定量限制，而直接局部测量不可用或可行。
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.
