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题名	古尔班通古特沙漠南部半固定沙垄表面风速变化规律研究
作者	盖世广
学位类别	硕士
答辩日期	2008
授予单位	中国科学院．新疆生态与地理研究所
导师	王雪芹，中国科学院新疆生态与地理研究所
关键词	古尔班通古特沙漠
其他题名	The Law of Airflow Velocity on the Semi-fixed Longitudinal Dune Surface in the Southern part of Gurbantunggut Desert
中文摘要	本项研究利用DETI可移动测风系统对古尔班通古特沙漠半固定沙垄进行实地观测，研究沙垄表面气流速度变化规律，发现坡脚风速、入射角和坡面形态对其有显著影响。主要结论如下：（1）受线形沙丘凸起床面形态的影响，风速由迎风坡脚至丘顶逐渐加速，在垄顶达到最大，至背风坡的中上部，风速剧烈降低，在背风坡的下部及坡脚又缓慢恢复。垄顶风速的大小与坡脚风速成很好的相关关系，即垄顶风速随坡脚风速的增大而线性增大。（2）在风速一定的情况下，迎风坡的风速放大率随入射角的增大而增大，同时背风坡相对于垄顶的风速降低幅度也越大，即入射角的大小控制着沙垄表面风速的变化幅度。不同坡度的地形通过扰动气流而影响风速的空间变化。风速放大率在缓而长的坡面上较短而陡的坡面要大，短而陡的坡面作为背风坡时风速的降低则更为剧烈。（3）总体来看，气流在迎风坡风向变化不大，基本保持在20°以下，至背风坡中上部变化最为剧烈，可达到90°，至背风坡底又逐渐恢复到原来的风向。背风坡风向的变化随入射角的增大而增大，但在入射角一致的前提下，发现风速值的大小对背风坡风向变化影响不大。坡面形态对背风坡风向变化也有一定影响。（4）垄顶风速放大率的存在，大大增加了沙垄顶部的输沙率和活动性，特别是在大角度入射的风力作用下，这种效果就更为显著。风速放大率的存在，从某种程度上讲是古尔班通古特沙漠长期以来在垄顶部广泛存在流动带的动力因素。（5）距地表不同高度处迎风坡上风速变化的趋势一致，随着高度的增加，风速放大率有所减小。背风坡上部的风速降低幅度，以200 cm高度最大，其次为80 cm，20 cm高度最小。沙垄表面距地表20cm高度与80cm高度处风速变化相关性比较好，与200cm高度处风速变化相关性较小，说明地表植被等下垫面条件至少影响到距地表80cm的高度。Field measurement of airflow at 2m high over semi-fixed longitudinal dune surface was made in the southern part of Gurbantunggut Desert in order to understand the various change of flow velocity over this dune type. It was found that wind velocity varied over the dune surface and the changes associated with primary wind magnitude and direction and slope morphology. The primary conclusion as flows: (1) Because of the influence of the linear dune’s heave surface the airflow velocity increased up the toss slope and decreased down in the upside lee slope, but it is resume slowly in the lee slope. There are good correlation between wind speed in the top and the slope. That is to say the wind speeds in the top increase along with the slope. (2) When the wind speeds in a certain time, the large the incidence angle between primary wind direction and dune is, the greater the extent of wind velocity tended to be. The landform in different grade affects the wind speed by harassing the airflow. The landform has a significant effect on the airflow as well. There is a slow change of wind velocity up or down the gentle slope but a great change when the slope is steep. (3) In the windward slope, the direction of wind changed little, and remained below the 20°.To the upper part of leeward slope, the direction of wind changed greatly, which could reach 90°, and to the bottom of leeward slope, it restored to original state. variation of the direction of wind increase with the rising of the incident angle. In the same incident angle, wind speed has little effect on the direction of wind in the leeward slope. Slope shape has some influence on the direction of wind in the leeward slope. (4) The magnify rate of the wind speed enhance the sand activities and sand transport in the top of the dune, especially in large angle incident. In some sense, magnify rate is the dynamical factor to the activity strip’s existence. (5) The variation tendency of the wind speed at different height, in the windward slope, was consistent. Magnification of wind speed decreased with the rising of height. In the 200cm of the leeward slope, the range of wind speed decreased is the largest, then is 80cm and 20cm. Height have a good correlation with wind speed at 20cm and 80cm, while the correlation was not obvious at 200cm.The results show that the height which underlying surface condition, such as vegetation cover and soil moisture effected on the wind speed can reached 80cm.
语种	中文
学科主题	水土保持与荒漠化防治
公开日期	2010-11-12
页码	共55页
内容类型	学位论文
源URL	[http://ir.xjlas.org/handle/365004/8086]
专题	新疆生态与地理研究所_中国科学院新疆生态与地理研究所(2010年以前数据)
推荐引用方式 GB/T 7714	盖世广. 古尔班通古特沙漠南部半固定沙垄表面风速变化规律研究[D]. 中国科学院．新疆生态与地理研究所. 2008.

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