【作者】 周毅；

【导师】 汤国安；

【作者基本信息】 南京师范大学 ， 地图学与地理信息系统， 2008， 硕士

【摘要】 在黄土高原地区,以沟沿线为分界的正地形与负地形在空间交错分布是黄土地貌基本景观特征,其此消彼长又是黄土地貌发育的重要特点。本研究首先阐述黄土高原地区正负地形概念模型,提出基于DEM的正负地形自动提取方法——坡面畸变邻域判断法,探讨了该方法的提取精度与应用适宜性;论文引入景观生态学的理论,研究黄土地貌正负地形所呈现的黄土地貌景观特征与指标体系。提出了一整套基于DEM有效提取与分析正负地形景观形态指标(形状指数、边界密度、破碎度、匀度指数、分维值等)、三维形态指标(平均高程差、平均坡度差、平均粗糙度比等)以及地形发育特征指标(蚕食度、逼近度等)的技术方法。以陕北黄土高原地区48个典型地貌类型区为研究样区,完成了正负地形的系列专题地图,通过对正负地形特征指标空间展延的分析,研究其在整个陕北黄土高原的空间分异规律,探讨黄土地貌正负地形的外在表现与地学内涵。实验结果显示,陕北黄土高原地区正地形约占60.5%,但在不同地貌类型区存在很大差异;正负地形系列化指标能够从各个不同侧面反映黄土地貌基本形态与发育特征。蚕食度指标通过正负地形面积比,揭示坡面的侵蚀程度以及地貌发育程度;沟沿线对流域边界的逼近度指标,从流域尺度反映流域地貌系统发育阶段。本研究结果在理论上有助于深化对黄土侵蚀地貌及其发育规律的认识,在实际应用中服务于黄土高原生态环境的建设。更多还原

【Abstract】 China loess plateau is world-wide famous for its peculiar and unique landforms. Distributing staggered spatially and zigzaggedly, the loess positive and negative terrain (hereafter called P-N terrain for short) are mainly separated by the loess shouderlines which is a key terrain structure line in the loess area. The study on the characteristics of P-N terrain and their interaction could be an effective clue for making a deeper investigation of loess landforms, e.g. loess terrain development, surface erosion at both local and regional scales.The study firstly expatiate the conceptual model of P-N terrain. Then a DEM based positive and negative terrain automatic extraction methods called "neighborhood judgment method of slope deformation" is developed. Then the extraction accuracy as well as the application suitability of this method are explored.The methodology of landscape ecology is employed to study loess landscape features constructed by P-N terrain. A series of quantitative indicators are proposed. They are two dimensional landscape indicators (including: shape index, boundary density, fragmentation degree, symmetrical index and fractal value), three dimensional shape indicators (including: mean-slope-difference, mean-elevation-difference and mean-roughness-worse) and terrain development indicators (including: nibble degree and approximation degree).A series of thematic maps was produced to investigate the spatial distribution of P-N terrain based on the DEMs from 48 test areas of typical loess landform areas in northern Shaanxi. According to the spatial distribution pattern and the development trend, the paper discussed the external manifestation and geographical meaning of P-N terrain. in Loess Plateau.Positive terrain covers 60.5% of the total loess area in northern Shaanxi, The extracted P-N terrain indexes could be found to possess of a rather strong relation with their landform characteristics. Index of nibbled degrees and approximation degrees shows the landform development and the developmental stages of drainage system within a watershed area. The study is hopeful to make a deeper understanding of loess erosion landforms and their development rules, as well as to play a great role in the reconstruction of ecological environment in Loess Plateau.更多还原