黄土高原沟谷地貌发育演化研究进展与展望

黄土沟谷是黄土地貌中最有活力、最具变化、最富特色的对象单元,黄土高原千沟万壑的地貌形态以及触目惊心的侵蚀状态也让区域内沟谷地貌的形成、发育及演化问题成为研究中焦点及前沿性科学问题。近年来,诸多学者采用地学测年法、特征表达法、监测模拟法力图实现对黄土沟谷发育演化进程中“过去-现代-未来”的科学认知。这些研究在相当程度上丰富了黄土沟谷发育过程的认知。本文梳理了黄土高原沟谷地貌演化相关研究的现状,并从黄土高原地貌演化、黄土沟谷发育、基于DEM的沟谷信息提取与表达等研究进行了系统的回顾、梳理与分析。此外,本文提出“黄土沟道剖面群组”概念与方法,试图从新的视角审视黄土沟谷地貌发育演化过程。沟道剖面在黄土沟谷发育演化进程中传递物质能量和累积地形动力,并通过径流节点的串联实现剖面群的连接与组合,形成独特的剖面“群组”模式;该沟道剖面群组是集黄土沟谷地貌特征与过程于一体的综合信息集成体,其三维空间结构是对黄土沟谷地貌发育演化的高度抽象与映射,并可望进一步丰富黄土高原数字地形分析理论与方法体系,为黄土高原黄土地貌成因机理与空间分异格局带来创新的认识。

Research Progresses and Prospects of Gully Landform Formation and Evolution in the Loess Plateau of China

Loess gully should be the most dynamic and changeable landform unit among the loess landforms in the Loess Plateau of China. In this plateau, the surface morphology presents thousands of gullies with a severe soil erosion pattern. This specific environment makes the area to a research focus both in the studies of geomorphology and soil erosion, especially the frontier questions of the formation and evolution of the gully landform. In the recent years, methods of geochronological dating, geomorphological feature expression, and monitoring simulation have been used by many scholars for better understanding of loess gully formation from the perspective of "past", "now", and "future". These advances have enriched our knowledge of loess gully formation and evolutionary processes. In this research, we systematically analyzed the research status quo and progresses of related studies on loess gully evolution in the Loess Plateau. These related studies include the landform evolution in the Loess Plateau, the loess gully formation, and the gully information extraction and expression using the DEM data. We argued that existing studies of loess gully formation and evolution should be further improved, with especially the help of theories and methods of the modern geographical information science. To this end, we proposed the concept of loess gully profile combination, trying to understand loess gully formation and evolutionary processes from a new perspective. The profile of gully transfers matter energy and accumulates terrain power during loess gully evolution. In addition, with the connection of runoff nodes, different gully profiles are connected and combined with each other, forming a specific pattern of gully profile combination. This combination should be a comprehensive information integration which integrates features and processes of loess gully landform. The three-dimensional spatial structure of the gully profile combination is an abstraction and mapping of loess gully landform evolution. The quantitative expression model of gully profile combination is expected to build, which should be oriented to loess gully landform evolution. This gully profile combination will help to achieve a new understanding of the loess gully formation mechanism during loess gully evolutionary processes, and to refine the gully evolution rules and patterns in the Loess Plateau. The gully profile combination is expected to further enrich digital terrain analysis methods.