基于多源数据的黄土高原（重点流失区）侵蚀沟提取及区域差异性研究

发布时间：2018-06-09 20:09

  本文选题：黄土高原 + 侵蚀沟　； 参考：《南京师范大学》2017年博士论文

【摘要】：侵蚀沟在黄土高原分布极广,是黄土地貌中物质交换最频繁、形态变化最剧烈的区域之一。黄土高原不同区域分布的侵蚀沟在形态上具有显著的区域差异性,这种差异性一方面塑造了不同的地貌景观,另一方面也影响着水土保持和农业生产布局。对侵蚀沟区域差异性研究不仅是探索侵蚀沟自身发育与分布规律的需要,同时也是黄土高原地貌、侵蚀、生态等地球系统科学研究的重要切入点。前人对黄土侵蚀沟区域差异性开展了一系列研究,但受制于研究数据和方法,还处于探索阶段。目前仍没有提出一套适合于黄土地貌的侵蚀沟自动提取方法体系;仍缺乏面向区域尺度的侵蚀沟特征定量分析指标体系;尚未对侵蚀沟区域差异性的影响机制进行剖析。对这些科学问题的进一步探讨,可望在黄土侵蚀沟相关研究取得突破性进展。本文首先基于多源数据,构建了黄土侵蚀沟自动提取方法体系,实现了对黄土高原水土重点流失区侵蚀沟的自动提取;在此基础上,设计了侵蚀沟特征分析指标,基于不同的流域层级,在不同空间尺度上剖析了侵蚀沟区域差异性特征,并实现了研究区侵蚀沟特征分区。最后,通过侵蚀沟特征与地形、土壤、植被覆盖度、土地利用等地理要素的相关性分析,剖析了侵蚀沟区域差异性的影响机制。论文的主要研究内容和及结论如下:(1)系统分析了现有侵蚀沟的定义,明确了本研究中侵蚀沟的基本界定,发育过程和基本特征。从侵蚀年代、形态特征、侵蚀特征、规模等级等角度进行了侵蚀沟的类型划分。此外,在现有的线性河网、正负地形分析等黄土侵蚀沟研究视角的基础上,进一步提出了面向对象化特征的侵蚀沟分析思路。(2)设计了一种基于高分辨率地形和影像数据的侵蚀沟自动提取方法,实现了对三个典型小流域样区(绥德窑家湾沟、安塞纸坊沟和长武下柳沟)侵蚀沟双层次特征的自动提取,并取得了较好的提取精度。(3)设计了基于中分辨率数据的侵蚀沟自动提取方法,针对大区域范围侵蚀沟提取需要,提出了融合地形骨架信息和影像特征的算法思路。在面向对象影像分析提取结果的基础上,融入汇水网络作为地形骨架信息,以修正侵蚀沟提取结果。结果表明,该融合策略有效弥补了中分辨数据对侵蚀沟特征表达不足,地形骨架信息对侵蚀沟提取的改进作用明显。基于该方法实现了对整个黄土高原水土重点流失区的侵蚀沟自动提取。(4)构建了侵蚀沟定量分析指标,通过不同层级流域单元下的特征分析和热点分析,从不同视角揭示了侵蚀沟的区域差异性特征。基于侵蚀沟割裂度和侵蚀沟主沟道纵比降两个指标,从侵蚀沟发育程度和侵蚀沟发展潜力两个角度构建分区体系,并最终得到了黄土高原水土重点流失区侵蚀沟特征分区图,共划分为9个侵蚀沟特 .征区。针对黄土侵蚀沟自身特征开展地理区划研究,是对现有土壤侵蚀分区、地貌分区的有效补充,可为黄土地貌、水土保持等研究提供了重要的参考。(5)探究了侵蚀沟特征与地形、土壤、植被覆盖、土地利用、土壤侵蚀强度的相关性,结果表明:侵蚀沟割裂度和侵蚀沟密度与土壤侵蚀强度具有较好的相关性,其中侵蚀沟割裂度的相关性更强,表明其在对区域土壤侵蚀评价中更具有优势。侵蚀沟特征与坡度和坡度坡长因子具有一定的相关性,但与面积高程积分、植被覆盖度的相关性较差。在土壤类型方面,黄绵土、褐土、栗褐土、灰褐土在黄土高原水土重点流失区分布较广,且易发育侵蚀沟,需要重点关注。本研究基于对象提取、格局分析、机制探究的地理学研究范式,揭示了侵蚀沟区域差异性的外在表现与内在机理,并推动数字地形分析与黄土地貌的研究。
[Abstract]:The erosion gully is widely distributed in the Loess Plateau. It is one of the regions with the most frequent material exchange and the most dramatic changes in the Loess landforms. The erosion gully in different regions of the Loess Plateau has a significant regional difference in morphology. On the one hand, it shapes different geomorphologic landscapes, on the other hand, it also affects soil and water conservation and agriculture. The study of regional differences in erosion gully is not only a need to explore the development and distribution of erosion gully, but also an important entry point for the geomorphology, erosion and ecology of the Loess Plateau. A series of studies have been carried out on the regional differences of the Loess erosion gully, but the research data and methods are also subject to the study. At present, it is still in the exploration stage. At present, a set of automatic extraction method system for erosion gully suitable for loess landforms is still not proposed; there is still a lack of quantitative analysis index system for the characteristics of erosion gully oriented to the regional scale, and the influence mechanism of the regional difference of erosion gully has not been analyzed. The further discussion on these scientific problems can be expected to be in the Loess erosion ditch. Based on multi source data, based on the multi source data, the automatic extraction system of loess erosion gully is constructed, and the automatic extraction of erosion gully in the soil and water erosion area of the Loess Plateau is realized. On this basis, the characteristic analysis index of the erosion gully is designed. Based on the different watershed levels, the analysis is made on different spatial scales. The regional difference characteristics of the erosion gully and the characteristic zoning of the erosion gully in the study area are realized. Finally, through the correlation analysis of the characteristics of the erosion gully, soil, vegetation coverage, and land use, the influence mechanism of the regional difference of the erosion gully is analyzed. The main contents and conclusions of this paper are as follows: (1) systematic analysis is made. The definition of erosion gully is defined, and the basic definition, development process and basic characteristics of erosion gully are clarified in this study. The types of erosion gully are divided from the angle of erosion age, morphological characteristics, erosion characteristics and scale grade. In addition, on the basis of the existing linear river network, positive and negative topography analysis and other loess erosion gully research perspective, it is further proposed. (2) an automatic extraction method of erosion gully based on high resolution terrain and image data is designed, and the automatic extraction of two layers of erosion gully in three typical small basin sample areas (Suide kiln house gully, Ansai paper mill ditch and Changwu Liu Gou) is realized, and a better extraction is achieved. (3) an automatic extraction method of erosion gully based on medium resolution data is designed. In view of the need for the extraction of erosion gully in large area, an algorithm for fusion of terrain skeleton information and image features is proposed. On the basis of the extraction results of the object oriented image analysis, the water sink network is incorporated as the terrain skeleton information to modify the erosion ditch. The results show that the fusion strategy effectively makes up the lack of the characteristic expression of the medium resolution data to the erosion ditch, and the improvement effect of the terrain skeleton information on the erosion ditch extraction is obvious. Based on this method, the erosion ditch of the soil and water erosion area in the whole loess plateau is automatically extracted. (4) the quantitative analysis index of the erosion gully is constructed. Based on the characteristics analysis and hot spot analysis under different hierarchical basin units, the regional difference characteristics of the erosion gully are revealed from different perspectives. Based on the two indexes of the erosion ditch and the longitudinal gradient of the main gully channel of the erosion gully, the zoning system is constructed from two angles of the erosion ditch development and the development potential of the erosion gully, and the soil and water soil of the Loess Plateau is finally obtained. The characteristic zoning map of the erosion gully in the key drain area is divided into 9 erosive gully. The geographical division of the Loess erosion gully itself is the effective supplement to the existing soil erosion area and the geomorphologic subarea, which can provide the important reference for the loess landform and soil and water conservation research. (5) the characteristics and terrain of the erosion gully and the soil are explored. The correlation of soil erosion intensity with soil, vegetation cover, land use and soil erosion shows that the erosion ditch separation and erosion density have a good correlation with soil erosion intensity, and the correlation of the erosion ditch separations is stronger, which indicates that the erosion gully is more advantageous in the evaluation of regional soil erosion. It has a certain correlation, but with area elevation integration, the correlation of vegetation coverage is poor. In terms of soil types, Huang Miantu, cinnamon, chestnut soil and gray cinnamon soil are widely distributed in the soil and water erosion areas of the Loess Plateau, and it is easy to develop erosion gully. This study is based on the object extraction, pattern analysis, and mechanism exploration geography. The research paradigm reveals the external manifestation and internal mechanism of regional differences in erosion gully, and promotes the research of digital terrain analysis and loess landform.
【学位授予单位】：南京师范大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S157
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本文编号：2000678