• “数字地形分析”专栏 •

### 基于地形剖面的黄土塬梁峁地形各向异性奇异强度研究

1. 1. 南京晓庄学院环境科学学院,南京 211171
2. 虚拟地理环境教育部重点实验室（南京师范大学）,南京 210023
• 收稿日期:2019-09-27 修回日期:2019-12-08 出版日期:2020-03-25 发布日期:2020-05-18
• 通讯作者: 曹建军 E-mail:jjcao@njnu.edu.cn
• 作者简介:曹建军（1976— ）,男,陕西延安人,博士后,主要从事地形空间关系研究。E-mail:jjcao@njnu.edu.cn
• 基金资助:
国家自然科学基金项目(41930102);国家自然科学基金项目(41871313);国家自然科学基金项目(41671389)

### Study on the Singularity Strength of Topographic Anisotropy of Loess Tableland, Ridge, Hill in Loess Plateau based on Terrain Profile

CAO Jianjun1,2,*(), TANG Guoan2, FANG Xuan1,2, LIU Yongjuan1, NA Jiaming2, ZHU Ying1, LI Jinlian1

1. 1. School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, China
2. Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Nanjing 210023, China
• Received:2019-09-27 Revised:2019-12-08 Online:2020-03-25 Published:2020-05-18
• Contact: CAO Jianjun E-mail:jjcao@njnu.edu.cn
• Supported by:
National Natural Science Foundation of China(41930102);National Natural Science Foundation of China(41871313);National Natural Science Foundation of China(41671389)

Abstract:

The characteristics of topographic relief variation are diverse from one landform type to another in the Loess Plateau. Great differences of topographic relief variation exist in different directions, which is known as topographic anisotropy. As fractal theory and geomorphology research become increasingly cooperative, Multifractal Detrended Fluctuation Analysis (MF-DFA) method, an effective means to quantitatively describe the nonlinear evolution process of complex sequences and the self-similar structural features formed by nonlinear evolution processes, manifests great potential in the study of topographic anisotropy of different landforms. In this paper, multifractal spectrum parameters were introduced to describe the variation characteristics of topographic anisotropy, in order to illustrate the local and global variation pattern of topographic anisotropy of different loess landforms. Based on 5 m-resolution Digital Elevation Model (DEM) data, three typical areas, Chunhua County of loess tableland, Ganquan County of loess ridge and Suide County of loess hill, were selected as the study areas. After that, MF-DFA of the variation characteristics of topographic anisotropy were conducted on these three areas. The results show that the topographic anisotropy of the three loess landform types has significant multifractal characteristics. The singularity strength of the topographic anisotropy from strong to weak turns out to be in the order of Chunhua, Suide and Ganquan counties. The probability of the singularity strength of topographic anisotropy in Chunhua County reaches the maximum at singular strength of 1.4, and there is a small peak around the singularity strength of 2.2. The probability of the singularity strength of topographic anisotropy in Ganquan County reaches the maximum at singularity strength of 0.7, with a second peak around the singularity strength of 1.8. Differently, the singularity strength of topographic anisotropy in Suide County is evenly distributed around 0.8, reaching the maximum at singularity strength of 0.8. The overall singularity strength of Chunhua and Ganquan counties are 1.4 and 0.7 respectively, while the probability distribution of topographic anisotropy in Suide County appears symmetrically. It can be concluded that the singularity strength of the topographic anisotropy is the highest in loess tableland, followed by that in loess hill. The singularity strength of the topographic anisotropy is the smallest in loess ridge. The results confirm that multifractal singularity strength is an effective method for the description and analysis of the topographic anisotropy of loess landforms, e.g., tableland, ridge and hill. This study can provide quantitative information support for the accurate classification of loess landforms as well as topographic indicators for regional water and soil erosion assessment.