黄土高原沟沿线研究进展与展望

Research progress and prospects of gully shoulder line in the Loess Plateau

沟沿线是黄土地貌正负地形类型划分和形态刻画的重要分界线,蕴含丰富的地貌形态信息,也是衡量沟谷侵蚀及地貌发育演化的重要基础。在前人对黄土地貌与数字地形分析的研究基础上,对沟沿线的概念模型、特征自动提取及其应用等相关研究进行回顾总结与评述,系统归纳当前沟沿线的研究成果与科学理论进展,对当前沟沿线研究现状进行深入思考并对其发展趋势做出展望。沟沿线的研究逐步成熟,目前常用的提取方法有4种:影像手绘法、基于地貌形态学法、基于图像分割法和基于点云数据法,但适用范围不广且提取精度有所差异;基于沟沿线的应用研究较为单一,大范围应用较少。沟沿线是黄土地貌的一条特殊线,将黄土地貌划分为典型二元结构,是深入了解黄土地貌、构建水土流失模型的关键。未来沟沿线的研究将重点从高精度沟沿线自动提取、沟沿线提取算法全局高效及局部保真、沟沿线与黄土高原沟壑之间的耦合关系等方面展开。

[Background]The gully shoulder line is the topographic structure line that can best reflect the morphological characteristics of loess landform.The shape,level,and spatial distribution of the gully shoulder line show the regional differences of loess geomorphology and is also an important basis for measuring gully erosion and landform evolution.The research of the gully shoulder line has gradually matured and has widely used.This paper systematically summarizes the current research results and scientific theoretical progress of the gully shoulder line,deeply ponders over the current research status,aiming to explore future research emphases and promote the subsequent research.[Methods]In this study,using“gully shoulder line”and“positive and negative terrain”as the keywords,relevant references were selected from CNKI,Web of Science core database and other domestic and foreign databases.Starting from the definition,this paper reviewed and summarized the conceptual model and extraction method of the gully shoulder line,and used VOSviewer software to analyze it,so as to clearly grasp the research hotspots and application directions of gully shoulder line.[Results]1)The gully shoulder line can reflect the internal evolution process of loess landforms.At present,the cognition of the gully shoulder line is relatively perfect,but its classification system is shortage.2)There are currently 4 commonly used extraction methods:Image hand-painted method,geomorphological morphology method,image segmentation,and point cloud data method,but the scope of application is not wide and the extraction accuracy is different,the traditional image hand drawing method has the highest accuracy,but it needs a lot of manpower and material resources.Compared with the traditional extraction method,the method based on geomorphic morphology is of higher efficiency,but the effect on extraction accuracy and continuity is poor.The method based on image segmentation is better in accuracy and extraction efficiency,but the algorithm of model method is more complex.The accuracy of point cloud data extraction method is second only to the traditional method.It can reflect the rich detailed information of the gully shoulder line,but it needs strong computer carrying capacity.3)The application research of the gully shoulder line is relatively simple,and the wide range application is less.The most widely used research is based on the loess landform,followed by the research on soil erosion of the gully,while the research on land use and vegetation cover is less.[Conclusions]The study proposes that the future research on the gully shoulder line should focus on the following aspects:High-precision automatic extraction,global efficiency and local fidelity of the extraction algorithm of the gully shoulder line,the coupling relationship between the gully shoulder line and the gully of the Loess Plateau,providing theoretical reference and new thoughts for researchers.