Knowledge Resource Center for Ecological Environment in Arid Area
| 干旱区防沙林带风沙沉积粒径变化及其动力学意义 | |
| 其他题名 | THE PARTICLE SIZE CHANGES AND ITS DYNAMIC IMPLICATION WITHIN THE SHRUB BARRIERS OF DESERT HIGHWAY IN ARID AREA |
| 汪言在 | |
| 来源期刊 | 第四纪研究
 |
| ISSN | 1001-7410 |
| 出版年 | 2013 |
| 卷号 | 33期号:2页码:376-387 |
| 中文摘要 | 通过野外地表沉积采样、植被调查和风速观测,本文对塔克拉玛干沙漠防护林带内地表风沙沉积粒径变化进行了研究。主要结论如下:1)防沙林带内沉积具有沙丘沙单峰分布的特征,在沙垄不同地貌部位,单峰对应的粒径区间存在粗细差异,与大地形的侵蚀堆积分布有关;2) EOF(经验正交函数)分解的第二特征向量与植株中上层高度的风速具有较好的相关性,反映了防护林带内外沉积动力的变化;3)由第二特征向量确定了粗、细敏感粒级的粒径分界范围为109.4 ~ 125.6mum,敏感粒级组分的百分含量与风速存在线形关系;4)使用敏感粒级组分的百分含量可评价沙垄各断面林带防护效益,林带内外粗、细敏感粒级组分的含量差异多在10%以上。研究结果反映了极端干旱环境下,风力变化对地表沉积粒径变化的影响,可以为工程防沙效益评价以及风沙沉积研究提供参考。 |
| 英文摘要 | Particle size and sorting characteristics of surface sediment are primarily dependent on antecedent wind condition. Particle size analysis is an essential approach for classifying sedimentary dynamics. Particle size fraction has been used to be as a proxy indicator of winter monsoon strength in Quaternary in the studies of Chinese loess sections. But correspondingly artificial particle size fraction (for example, the diameter of the particle < 5mum is classified as clay; 5.0 ~ 62.5mum as silt sand; 62.5 ~ 125.0mum as very fine sand; 125 ~ 250mum as fine sand; 250 ~ 500mum as medium sand;>500mum as coarse sand) was often used to qualify the effect of wind speed on the surface sediment in previous studies. Whether the artificial method is reasonable is still debatable. In this study, we aimed to establish a proxy indicator to quantify the wind speed effect on surface sediment particle size distribution based on the correlation between the magnitude of wind speed and fraction of dominant particle size. The field work has been undertaken in a longitude dune field in the central of Taklimakan Desert, located in the site of K352 along the Desert Highway, near the small town of Tazhong. The longitude dune covers about 2.7km between the latitude of 38°54’28.75"N and 38°55’58.06"N and longitude 83°32’13.87"E and 83°32’25.41"E. The sand protection system along the highway was correspondingly constructed to keep the sand off the highway in windy ays, which includes shrub barriers and artificial barriers. The artificial barriers have lost its protective role, but meantime shrub barriers still work. The width of the shrub barriers perpendicular to the highway is about 78m, while 48m for the upwind side and 30m for the downwind side. The appearance of the shrub barriers not only modified the overlaying surface along the Desert Highway, but also influenced the near-surface wind fields and thus minimized the movement of sand flow. This facility also provided us a case study of how surface wind speed might affect the sediment particle size distribution. To achieve this goal, we firstly collected 92 samples in the depth of 0 ~ 5cm below the ground surface from five cross-sections located on the longitude dune, among which 15 samples was collected from the bottom of the windward slope, 18 samples from the central of the windward slope,20 samples from the top of the longitude dune, 15 samples from the central of the leeward slope and 24 samples from the bottom of the leeward slope. We also got the data of wind speed at each sand sample site by using measuring instruments in the field. And then we used EOF (empirical orthogonal function) method to quantify the spatial variation of the particle size fraction, finally analyzed the correlation between wind speed and the dominant particle size fraction, by which we want to build up a proxy indicator or sensitive grain size fraction of wind speed based on the surface sediment samples data. Our main results are as follows: (1) Surface sediment particle size has a single peak distribution character within shrub barriers, which inherits the original distribution patterns of dune sediment. Particle size corresponding to single peak has a difference value at different topography positions of longitude dune. The coarse sand concentrated in the central of windward slope, which related to the erosion and accumulation distribution of large terrain. (2)The correlation between the second eigenvector and wind speed along the crosssection is quite nice. The spatial distribution of the second eigenvector can be used as a sensitive proxy of wind speed. (3) Two grain-size distribution patterns are observed that of the finer grain-size fraction(≤ Xmum, 125.6mum≥ X≥109.4mum) and that of a coarser grain-size fraction (≥Xmum, 125.6≥mumX≥109.4mum), which were defined as sensitive size fraction corresponding to wind speed variation. |
| 中文关键词 | 林带 ; 粒径变化 ; 动力意义 |
| 英文关键词 | shrub barrier particle size changes dynamic implication |
| 语种 | 中文 |
| 国家 | 中国 |
| 收录类别 | CSCD |
| WOS类目 | GEOSCIENCES MULTIDISCIPLINARY |
| WOS研究方向 | Geology |
| CSCD记录号 | CSCD:4772458 |
| 来源机构 | 北京师范大学 |
| 资源类型 | 期刊论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/229422 |
| 作者单位 | 北京师范大学, 地表过程与资源生态国家重点实验室;;防沙治沙教育部工程研究中心, 北京 100875, 中国 |
| 推荐引用方式 GB/T 7714 | 汪言在. 干旱区防沙林带风沙沉积粒径变化及其动力学意义[J]. 北京师范大学,2013,33(2):376-387. |
| APA | 汪言在.(2013).干旱区防沙林带风沙沉积粒径变化及其动力学意义.第四纪研究,33(2),376-387. |
| MLA | 汪言在."干旱区防沙林带风沙沉积粒径变化及其动力学意义".第四纪研究 33.2(2013):376-387. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [汪言在]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [汪言在]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [汪言在]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
