Knowledge Resource Center for Ecological Environment in Arid Area
| 腾格里沙漠风沙地貌特征的空间变化 | |
| 其他题名 | Spatial Changes of Aeolian Geomorphology in Tengger Desert |
| 文青 | |
| 出版年 | 2016 |
| 学位类型 | 博士 |
| 导师 | 董治宝 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 风沙地貌学以风沙流和沙丘做为研究对象，对风力作用下物质运动形成的地表形态特征、空间组合规律及其形成演变等方面进行研究。风沙地貌在全球干旱半干旱地区广泛分布，但不同地区的风沙地貌各有不同，都有其自己的典型特点，风沙地貌的形成演变与区域环境有密切的关系，通过不同区域的研究可以全面揭示风沙地貌的形成与演变规律成为区域风沙地貌学研究的任务。腾格里沙漠是中国第三大流动沙漠，格状沙丘典型，分布面积广。本文在全面认识腾格里沙漠风沙地貌特征的基础上，编制了风沙地貌图，结合遥感影像资料，尝试应用地貌格局分析法分析腾格里沙漠沙丘的地貌格局参数。通过MATLAB平台对卫星影像进行处理，利用沙丘迎风坡与背风坡在卫星影像中成像的灰度差异，对沙丘脊线进行提取，获得沙丘脊线长度、沙丘间距、走向等沙丘地貌格局参数。数据分析结果显示，腾格里沙漠沙丘脊线长度的高值区主要分布在西部、东部、南部，低值区主要分布在北部、中部和西南部。脊线长度总体上显示出自北向南增大的趋势。自西北向东南方向，沙丘长度值也在逐渐变小。沙丘间距的高值区主要分布在腾格里沙漠北部、西部地区，中部为低值区。腾格里沙漠沙丘缺陷密度的高值区主要分布在东北部地区，缺陷密度值总体上显示出自北向南逐渐减小的趋势。格状沙丘是腾格里沙漠沙丘的主要类型，面积占沙漠面积的37.9%，根据影像特征和地形图上的布局，格状沙丘在大小、形态结构上还存在不同程度的差异，所以将格状沙丘细分为方格状沙丘和长格状沙丘。根据脊线长度累计概率图，方格状沙丘主梁长度最短，长格状沙丘的副梁长度最小。沙丘主梁的长度从西北到东南递减。长格状沙丘的主梁平均间距最短。方格状沙丘的副梁平均间距最大，沙丘副梁的间距从西北到东南方向递增。缺陷密度与脊线长度在空间变化上的对应关系较好，脊线长度越大，其缺陷密度值就越小；而缺陷密度与沙丘间距在空间变化上的对应关系差。 尝试利用Werner and Kocurek和Ewing et al的拟合曲线，根据格状沙丘的间距与缺陷密度估算了腾格里沙漠格状沙丘的大致形成时间，其大约形成于1.3 ka BP。在不同区域沙丘的形成时间不同，反映了影响风沙地貌发育的风况、下伏地形等因素的区域差异及其复杂性。这些因素并未从根本上影响沙丘的总体地貌格局和演化趋势，使得沙丘地貌格局记录了其形成时间的可靠信息。 |
| 英文摘要 | Aeolian geomorphology is the study of the characteristics of landsurface patterns, spatial combinations, formation and development. Aeolian geomorphology are widely distributed in arid and semi-arid regions. Different areas have different typical characteristics. On the basis of knowledge of the formation of Aerlian landform and its development principle of the Tengger Desert, the morphologic characteristics of dune networks are initially proved.According to the grond observation and field investigation, a classification system of sand dunes suitable to the Tengger Desert was developed, in combination of interpretation of remote sening images and, as a result, a geomorphology map of the Tengger Desert was compiled.In this paper, to provide information on the geomorphology, we analyze the geomorphologic patterns of the dunes in Tengger Desert using MATLAB to process remote-sensing images. Four important geomorphic pattern parameters, ridge length, spacing, orientation and defect density, are analyzed. As a whole, length tends to increase on moving from the north to the south. By comparing the isopleth plot of the mean dune length with the geomorphological characteristics, it can be seen that the area with a high length are mainly distributed in the west, east, south, and the area with a low length are mainly distributed in the northern, central and southwest. The area with a high dune spacing are mainly distributed in the northern and western region, and low spacing area are in the central Tengger Desert. The defect density dereases from north of the desert to south.There are dozens of dune areas in the desert, and dune networks are found in 17, 950 km2 of the desert (i.e., 37.9% of the entire desert). Based on an examination of image features and dune locations in a topographic map (1:400, 000 Geomorphologic Map of The Tengger Desert), two kinds of dune networks differ in size and morphological structure. We divided them into square dune networks and rectangular dune networks. According to cumulative probability distributions of ridge length for dune networks, the length of the primary ridges decreases from northwest to southeast (i.e., from the rectangular dune networks at site B to the square dune networks at site A). The length of the secondary ridges increases from northwest to southeast. The regions with low and high spacing occur at roughly the opposite range of positions as in the distributions for the ridge length, the average spacing of rectangular dune networks is shorter than square dune networks. For the secondary ridges, the regions with low and high spacings are similar greatly to the positions of ridge length.Moving from northwest to southeast, the range of the orientation generally increases, and the wind regime that becomes increasingly complex from northwest to southeast (i.e., from the rectangular dune networks at site B to the square dune networks at site A).We use the spacing and defect density data to estimate the construction time of dune networks in light of Werner and Kocurek’s (1999) and Ewing et al. (2006)’s successful experiences and find that the dune networks in the Tengger Desert formed since about 1.3 ka B.P. Different parts of the study area have different dates for the start of dune formation. This may have resulted from differences in the wind regime, which strongly influence the development of aeolian geomorphology, but differences in the underlying topography and other factors would also have affected dune initiation and evolution. |
| 中文关键词 | 风沙地貌 ; 地貌格局参数 ; 地貌格局分析 ; 格状沙丘 ; 腾格里沙漠 |
| 英文关键词 | aeolian geomorphology geomorphological parameters geomorphic pattern analysis dune networks Tengger Desert |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287698 |
| 推荐引用方式 GB/T 7714 | 文青. 腾格里沙漠风沙地貌特征的空间变化[D]. 中国科学院大学,2016. |
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