基于SRTM DEM数据的中国地形起伏度分析研究

Analytical Study of the Relief Amplitude in China Based on SRTM DEM Data

地形起伏度是区域水土流失评价的最佳地形指标,地形起伏度的分析研究对于区域水土流失定量评价具有重要意义.首先利用邻域统计分析法,在不同大小邻域窗口下(2×2,3×3,4×4,,25×25,30×30,35×35,40×40,45×45,50×50)对中国地形起伏度进行了提取;然后运用均值变点分析法完成了最佳统计单元的计算,结果 11×11网格大小可作为曲线变化的拐点,即为曲线由陡变缓的阀值.从而得出基于90m×90m SRTM DEM数据的中国地形起伏度提取的最佳统计单元为11×11网格大小;接着完成了中国水土流失地形起伏度分级图的绘制;最后对地形起伏度特征作了初步分析.

The relief amplitude is the best topographic index for evaluating the regional soil and water loss, to study relief amplitude has an important significance for the regional soil and water loss quantitative evaluation. First, the relief amplitude of China was extracted with the neighborhood statistics analysis method at different neighborhood windows（2 x 2,3 × 3,4 × 4,..-, 25 ×25,30 ×30,35 × 35,40 × 40,45 × 45,50 ×50）. Then, the best statistical unit was calculated by using the mean change-point analysis method, the results showed that the curve appeared the inflection point at the 11 x 11 （0. 755161km2） grid unit,which may be called ＂threshold＂, before the inflection point, the curve rose very rapidly, but it grew comparatively much slower after the inflection point, that is to say, the 11 × 11 grid unit was the best statistical unit for extracting the relief amplitude in China based on the 90m resolution SRTM DEM data, and the relief amplitude of the 11 × 11 grid unit can reflect the actual terrain and the features of soil and water loss. Next, the drawing of China relief amplitude grade was completed. Finally, the features of relief amplitude were analyzed.