Stabilization of Dune Surface and Formation of Mobile Belt at The Top of Longitudinal Dunes in Gurbantonggut Desert, Xinjiang, China
Stabilization of Dune Surface and Formation of Mobile Belt at The Top of Longitudinal Dunes in Gurbantonggut Desert, Xinjiang, China
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发表时间：
2003
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通讯作者：
Wang Xue
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作者：
Wang Xue
古尔班通古特沙漠位于新疆北部准噶尔盆地，面积约4.8万km，是我国第二大沙漠。受西风影响，沙丘类型以固定沙丘和半固定沙丘为主。沙丘顶部存在一条移动的带，引起了许多研究者的关注。本文在分析影响沙丘表面稳定性垂直变化的主要因素的基础上，特别是在野外侵蚀和存款过程的观测基础上，对沙丘表面的稳定性和移动的带的形成进行了讨论，并得出了一些结论。(1)古尔班通古特沙漠固定沙丘和半固定沙丘的自然环境总体上具有一定的特点。沙丘表面稳定性的垂直变化主要受沙物质组成、土壤类型、含水量、植被覆盖度和土壤微生物结皮分布等因素的影响。沙丘不同部位土壤抗风蚀能力不同，导致沙丘表面土壤移动的程度存在空间变化。研究表明，从沙丘底部到沙丘顶部，沙的活动呈现由弱到强的变化。(2)沙丘表面的移动的带实际上是沙丘顶部10~40 m宽的冲淤频繁区。侵蚀区一般位于迎风坡，存款一般位于背风坡，二者在沙丘的某一部位交替发生。风沙存款和侵蚀的强度受风况和地表条件的控制。古尔班通古特沙漠沙丘的动态格局是：纵向沙丘顶部的沙粒由一侧向另一侧交替搬运，一般沿山脊沿着向前移动，而沙丘底部则保持不变。
Gurbantonggut Desert, located in Junggar Basin in north Xinjiang, with an area of \{48 000\} km2, is the second largest desert in China. Affected by the west current, fixed and semi\|fixed dunes are the main types. There is a mobile belt at the top of dune, which has aroused the concern of many researchers. In this paper, based on analysis of the main factors affecting the vertical variations of dune surface stabilization, especially on field measurement of erosion and deposit process, the stabilization over the dune surface and the formation of mobile belt are discussed and some results are obtained.\;(1) Generally speaking, fixed and semi\|fixed dunes in Gurbantonggut Desert are characterized by natural environment. The vertical variation of stabilization on dune surface is mainly affected by some factors, such as composition of sand materials, soil type, water content, plant coverage and the distribution of soil microbiotic crust. The ability of soil resisting wind erosion various at different parts of dunes, which leads to the spatial change of mobile degree on dune surface. The research shows that, from the bottom to the top of dune, there is a change of sand activity from weak to strong.\;(2) In fact, the mobile belt on dune surface is the area with frequent deposition and erosion, a width of 10～40 m at the top of longitudinal dunes. Erosion area exists at windward slop and deposit at leeward in general, both of them happen alternately at one part of dunes. The intensity of sand deposit and erosion is controlled by the wind regime and ground surface condition. The dynamic pattern of dunes in Gurbantonggut Desert is that the sand particles at the top of longitudinal dunes are transported alternately from one side to the other and generally move forward along the ridge, while the base of dune keeps on unchanged.