陕北黄土高原地貌空间分形特征

Spatial Fractal Properties of Loess Plateau in the Northern Shaanxi Province of China

陕北黄土高原因其地貌类型既丰富又典型,是地貌研究的重要区域,已有不少关于本地区的地貌研究成果.然而对分维值的空间分异及其与地貌特征之间的关系的认识还十分有限.因此,本文评估了用分形方法探索地形和河网的分维特征的应用适宜性.结果显示,计算分维值的窗口大小影响结果的空间分布特性.当格网大小为32时是最适合黄土高原地区的分维值估算,其结果与其他研究展示的地貌分类一致.网格大小分别为16和64时,会产生高估或低估分维值的结果.对河网的分形研究表明,分维值与Strahler级数相关,河网级数越多,分维值越大.河网结构的分形特征还有待进一步研究.本文研究成果可为地貌特征和其他地区的分形研究提供参考.

The Loess Plateau of the Northern Shaanxi Province of China is an important area of research for geomorphological studies. Several studies have been conducted in the past in this particular subject of geomorphology. However,spatial variability of fractal dimension( FD) vis-à-vis its relationship with landform characteristics have been limited.Thus,the paper assessed the application of fractal methodology to investigate the fractal properties the terrain and stream networks. The results show that Grid Size( GS) for the FD estimation affects the distribution of the values obtained. It was recommended that for the Loess Plateau understudy,a GS of 32 was realistic and mimics well with the landform classification types provided by other studies. The GS of 16 and 64 underestimates and overestimates the FD respectively. The FD values for the stream networks indicate that Strahler Numbers( SN) and FD are related. For instance,the higher SN,the higher FD. However,a more in-depth analysis of the SN and FD needs to be conducted in future studies. The findings from this study could provide a baseline support for future research on geomorphology in the Loess Plateau and support for other regions interested in similar work.