| 新月形沙丘迎风坡形态及沉积物对表面气流的响应 |
| |
| 引用本文： | 张春来,郝青振,邹学勇,严平.新月形沙丘迎风坡形态及沉积物对表面气流的响应[J].中国沙漠,1999,19(4):359-363. |
| |
| 作者姓名： | 张春来 郝青振 邹学勇 严平 |
| |
| 作者单位： | 1. 中国科学院,兰州沙漠研究所,甘肃,兰州,730000
2. 中国科学院,地质研究所,北京,100029 |
| |
| 基金项目： | 中国科学院资源与环境重大项目!（KZ951－B1－206） |
| |
| 摘 要： | 对孤立新月形沙丘迎风坡风速的野外实测和计算表明，沙丘迎风坡表面风速廓线呈非对数关系，近地面剪切风速和输沙强度由坡脚至丘顶总体呈递增趋势，但同时随断面坡度的增减而发生相应的变化；沿断面输沙率的变化导致蚀积强度的改变，表现为沙丘迎风坡坡度变缓的部位沉积大于侵蚀，其它部位侵蚀大于沉积，其中丘顶输沙率和侵蚀强度最大。在沙丘形态上，表现为坡度减缓的部位沉积变凸、其它部位因侵蚀变凹以及坡脚和丘顶的前移。变凸和变凹部位反过来又制约着表面剪切风速的相应变化。粒度分析也表明，沙丘迎风坡表面粒度特征主要取决于表面蚀积状况，同断面形态表现出密切的相关性。
|
| 关 键 词： | 新月形沙丘 剪切风速 输沙率 蚀积强度 断面形态 |
Response of Morphology and Deposits to Surface Flow on Windward Slope of Barchan Dune |
| |
| ZHANG Chun-lai,HAO Qing-zhen,ZOU Xue-yong,YAN Ping.Response of Morphology and Deposits to Surface Flow on Windward Slope of Barchan Dune[J].Journal of Desert Research,1999,19(4):359-363. |
| |
| Authors: | ZHANG Chun-lai HAO Qing-zhen ZOU Xue-yong YAN Ping |
| |
| Abstract: | Field observation and theoretical analysis of wind velocity on windward slope of a isolated barchan dune indicated that velocity profile is non logarithmic; shear velocity and sand transport increase from foot of slope to the top as a whole though change correspondently with increase or decrease of the slope gradient. Changes of sand transport along windward slope lead to the variation of the intensity of erosion and deposition, to say concretly, erosion is more intense than deposition where slope gradient increases and deposition is greater than erosion at other locations. On the whole slope sand transport and net erosin is the greatest at the crest. Morphologically, net erosion at the foot and the crest results in forward movement of the dune, locations of erosion where slope degree increases and locations of deposition where slope gradient decreases will gradually become concave and convex respectively which inversely have a strong influence on surface flow. Therefore, correlationship among shear velocity, sand transport, intensity of erosion and morphology of windward slope plays a very important role in the evolution of barchan dune. Grain size analysis also indicates that grain size characteristics are mainly influenced by intensity of erosion or deposition and morphology of windward slope. |
| |
| Keywords: | barchan dune shear velocity sand transport intensity of erosion slope morphology |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
|
