基于流域单元的黄土地貌正负地形因子量化关系模拟

Simulation of quantitative relationship between positive and negative topographic factors of loess based on catchment unit

正负地形是黄土高原地貌形态表达的重要参数,也是现代沟谷侵蚀和发育研究的重要切入点,对于流域形态发育的定量化描述有重要意义。文中以典型自然流域为基本单元,在沟谷发育明显的陕北-晋西-陇东地区选择86个样区,利用1:10000比例尺5m高分辨率DEM数据,提取样区内多视角刻画地貌形态的正负地形因子指标,并进行流域地貌形态特征分析;在此基础上采用数理统计与地理建模的方法,重点探讨正负地形因子间的关联性,进一步实现基于多因子的量化模型的构建,以揭示地形因子信息与流域沟谷发育的内在联系。结果表明,蚕食度(Y)与沟壑密度(X_1)、平均坡度差(X_2)及破碎度(X_3)能较好地刻画流域地貌发育形态,并存在着线性函数关系:Y=0.069*X_1-0.01*X_2+0.009*X_3+0.239,拟合度达0.868。该模拟方法在黄土地貌形态发育的研究中有着重要的理论意义,是数字地形模拟与信息挖掘的一次有益实践。

The positive and negative topography is an important parameter for morphological expression of the Loess Plateau,and also an important entry point for the study of modern gully erosion and development.In this research,a typical natural catchment was taken as the basic geomorphologic unit,and 86 sample areas were selected in the area with obvious development of gullies in the Loess Plateau.With the 1:10,000 scale and 5 m high-resolution DEM data,positive and negative topographic factors from multiple perspectives were extracted,and the morphological characteristics of the catchment were analyzed.On this basis,mathematical statistics and geographical modeling were adopted to explore the correlation between positive and negative terrain factors,and to further realize the quantitative model simulation and construction based on multiple factors,so as to reveal the relationship between terrain factor information and the development of catchment gully.The results show that the erosion degree(Y),gully density(X1),average slope difference(X2)and fracture degree(X3)could describe the geomorphological morphology of the catchment well,and there was a linear function relationship:Y=0.069*X1-0.01*X2+0.009*X3+0.239,and the simulation accuracy was 0.868.The simulation method has important theoretical significance in the study of loess geomorphologic morphological development and is a useful practice of digital terrain simulation and information mining.