绿洲-沙漠过渡带柽柳灌丛沙堆表面的蚀、积特征

灌丛沙堆表面的蚀、积特征直接影响着沙堆的形成和发育，是研究灌丛沙堆的重要方面。选择策勒绿洲-沙漠过渡带内半固定沙地和流动沙地上的各一个独立柽柳沙堆作为表面蚀、积特征的定点观测对象，运用地形测量结合插钎法对每场大风后沙堆表面的蚀、积量与蚀、积分布状况进行计算分析。结果表明：（1）处于半固定沙地的柽柳沙堆，整体蚀、积空间分布规律不显著且蚀、积量相对较少，以微弱的蚀、积变化为显著特征，形态相对稳定。与之相对，处于流动沙地的柽柳沙堆，整体具有显著的空间分布规律和较高的蚀、积强度，这表明柽柳沙堆所处环境的沙源供给强度是控制沙堆单体规模的主要因素之一。（2）伴随着柽柳灌丛开始萌动到逐渐形成一定的灌丛覆盖，沙堆表面由大面积侵蚀逐步转为积沙，风蚀退缩到沙堆两侧且总体上沙堆体积在年内呈先减小后增大的波动状态。（3）柽柳灌丛沙堆以灌丛内部具有覆盖的保护区域及背风侧大面积稳定积沙，迎风和两侧区域强烈风蚀为主要蚀、积分布特征。

The surface erosion-deposition characteristic of Tamarix ramosissima nebkhas in Cele oasis-desert ecotone

The erosion-deposition characteristic of sand drift around the single nebkhas could directly influence the forming and development of nebkhas, which is an important aspect in nebkhas research. Using plugging sticks and topographic survey method, the volume and distribution characteristics of the Tamarix ramosissima nebkhas＂ surface erosion-deposition in two different sandy land in the Cele oasis-desert ecotone have been discussed in this paper. The results showed as follows. （1）In semi-fixed sandy land, slight erosion-deposition and stable shape of nebkhas were the main characteristics, but the erosion-deposition distribution regularity of the nebkhas was not obvious. On the contrary, the Tamarix ramosissima nebkhas exhibited high-intensity erosion- deposition and prominent distribution characteristics in shifting sandy land, which demonstrated the sand supply was one of the major factors of determining the scale of single nebkhas. （2）The wind erosion of the nebkhas entire surface converted slightly to sand deposition and the area of wind erosion retreated gradually to the two sides of nebkhas with growing of Tamarix ramosissima thickets. The annual volume of nebkhas was in and then increased. （3）Spatially, wind erosion nebkhas, and sand deposition mainly happened a state of fluctuation, which was firstly decreased occurred in the windward slope and two sides of on the thickets covering area and leeward slope of nebkhas.