摘要
[目的]为了分析3个不同下垫面近地表风沙流结构差异及输沙粒度特征,为输沙模型的建立提供理论依据。[方法]对策勒绿洲—沙漠过渡带风速梯度和输沙率进行野外观测,采用拟合函数回归方法分析。[结果]在0—200cm高度范围内,流沙地近地表输沙率或输沙通量与高度服从指数函数或对数函数关系,且拟合程度较高;半固定沙地近地表输沙率或输沙通量随高度服从指数函数关系,拟合程度中上等,稍差于流沙地;固定沙地输沙率随高度变化服从多项式函数关系,拟合程度中等—差。[结论]平均风速较大时,流沙地、半固定沙地地表输沙率或输沙通量随高度变化多服从指数关系,且拟合程度好于平均风速较小的输沙阶段;近地表跃移、蠕移沙粒无论在垂向还是在水平方向上,离地表越高或离绿洲越近其各高度输沙率和沙粒平均粒径都有变小和变细趋势,在水平方向上流沙地输沙沙粒分选性依次好于半固定沙地、固定沙地,分选性多属于中等或中等偏上;所有输沙沙粒的偏度值分布在-0.06~0.05之间,越靠近绿洲输沙沙粒越细;所有跃移、蠕移沙粒峰态值分布在0.92~1.05之间,属于中等峰态。
[Objective] In order to analyze the differences of sand flow structure and characteristics of grain size of sand transportation particles near ground surface on three different landscape types, which can be used by providing theoretical basis for setting up sand transportation models. [Methods] We carried out the field observation on wind velocity gradient and sand transportation rate on Cele desert--oasis ecotone, and fitted regression functions. [Results] There was an exponential or logarithm function relationship between sand transportation rate or sediment flux and height at the range from 0--200 centimeters above ground surface on mobile sandy ground. An exponential functional relationship was found between sand transportation rate or sediment flux and height near surface on semi-fixed sandy land and the fitting degree was moderate and well moderate degree which was a bit worse than that on shifting sandy ground. There was polynomial functional relationship between sand transportation rate or sediment flux and height near ground surface on fixed sandy land and the fitting degree was between medium degree and worse degree. [Conclusion] When the mean wind velocity was comparatively greater, an exponential relationship was always detected between sand transporta tion rate and height and the fitting degree was better than that in phases with slower wind velocity. Whereas on vertical or horizontal directions for sand saltation and creeping sand particles near ground surface, the sand transportation rate and mean grain size on different heights became smaller and finer with increasing dis- tance to ground surface or shortening distance to oasis on horizontal distance. Sorting effect of sand transpor- tation particles on shifting sandy land was better than that on semi-fixed and fixed sandy lands on horizontal direction, which were most belonged to moderately well sorted. The sand has became finer skewed when the sand transportation particles is nearer to the oasis. The skewness of all sand transportation particles inclu- ding saltation and creeping particles is in the range between --0.06 and 0.05. The kurtosis is in the range from 0.92 to 1.05, which belongs to mesokurtic.
出处
《水土保持通报》
CSCD
2015年第1期25-33,共9页
Bulletin of Soil and Water Conservation
基金
新疆维吾尔自治区重大科技专项项目子课题"绿洲外围节水型生物防护体系构建及可持续经营技术开发与示范"(201130106-1)
新疆师范大学地理科学与旅游学院地理学博士点支撑学科开放课题
新疆维吾尔自治区重点实验室"新疆干旱区湖泊环境与资源实验室"基金项目"新疆策勒河流域下游塔克拉玛干沙漠南缘风沙环境演变研究"(XJDX0909-2013-08)
关键词
风沙流结构
输沙
粒度
特征
沙漠—绿洲过渡带
策勒
sand flow structure
sand transportation particles
grain size
desert--oasis ecotone
Cele County of Xinjiang Wei Autonomous Region
