中国西南地区地形起伏度的最佳分析尺度确定

Optimal Statistical Unit for Relief Amplitude in Southwestern China

[目的]确定中国西南地区地形起伏度的最佳分析尺度并进行地形分级,明确区域地形结构特点并进行地貌结构划分。[方法]以ASTER GDEMv2数据为基础,通过Python模块编程,利用窗口分析方法提取西南地区各典型地貌以及整个区域n×n(n=2,3,4,…,181,182,183)窗口下的平均地形起伏度,进而采用均值变点分析方法确定最佳统计窗口。[结果](1)西南地区地形起伏度的最佳分析尺度为2.43km^2;(2)区域地形起伏度以中小起伏为主,其中小起伏(200~500m)占38.68%,中起伏(500~1 000m)占23.58%;(3)从空间分布来看,西南地区的地形起伏度呈现中部高,东南部次之,西北部和东北部较低的特征。[结论]以2.43km^2为最佳统计窗口提取的西南地区地形起伏度符合区域地形起伏特征,同时较好地兼顾了各地貌类型的起伏特点。

[Objective] The objective of this article is to determine the best statistical unit to extract and classify the relief amplitude of Southwestern China, and then the characteristics of the amplitude structure and the classification of geomorphologic structure can be determined.[Methods] Based on ASTER GDEMv2 data and through Python module programming, the average relief amplitude in the Southwestern China and the typical experimental areas was extracted at n×n windows （n=2,3,4,…,181,182,183）, and the best window area was calculated by the mean change point method.[Results] ① 2.43 km2 was the optimal statistical unit for extracting amplitude relief in the study area. ② Fluctuation of terrain was moderate and low in the study area, with the relief amplitude between 200 m to 500 m having the highest proportion （38.68%）, and that between 500 m to 1 000 m accounting for 23.58%. ③ As for the spatial distribution, the relief amplitude of the middle region was generally higher than that of other regions, followed by the southeast, lower in the northwest and northeast.[Conclusion] The method, computing relief amplitude with optimum statistical unit of 2.43 km2, conformed to the regional terrain characteristics and balanced the various landform types.