A Study for the Dynamics of Dunes in Various Environment

本项目主要通过计算机模拟和理论分析，研究了不同环境下沙丘格局的形成过程及其动态变化，包括非稳定风作用下沙丘格局的选择机制、半干旱区沙丘格局的形成、相互作用的沙洲动态变化和河道格局的动态变化。结果表明：（1）非定常风作用下沙丘走向的选择机制可以简单地用线性不稳定模态的叠加来解释;（2）植被沙丘的形成，特别是抛物线沙丘的形成，可以用植物生长与输沙之间的相互抑制动力学来模拟。（3）新月形沙丘的大小分布可以用沙丘的群动态来简单地解释。（4）河道动力学可以用与沙丘相似的模型来处理，通过这些课题的研究过程，我们得到了统一处理各种地貌过程的基本方法，这是我们下一步研究的方向。

In this project, using computer simulations and theoretical analysis, we investigated the pattern formation process of dunes and their dynamics in various environment.Specifically, i) pattern selection mechanism of dunes under unsteady wind, ii) pattern formation of dunes in semi-arid region, iii) dynamics of interacting barchans, and, iv) pattern dynamics of river channels, are intensively studied.For these respective subjects, we found that i) the selection mechanism of dunes' trend under unsteady wind is simply explained by the superposition of linearly unstable modes, ii) the formation of vegetated dunes, especially parabolic, are simulated using a inter-suppression dynamics between plant growth and sand transport. iii) size distribution of barchans can simply be explained using the group-dynamics of dunes. iv) dynamics of river channel is treatable using a similar model as that for dunes.Through the research process of these subjects, we got fundamental methodology for the unified mathematical treatment of various geo-morphological processes, which is the next issue of our study.