无定河流域黄土区地貌要素之统计特征及其趋势面与聚类分析

根据野外考察和1/50,000地形图上等密度取样量测统计,表明研究区内平均沟谷密度为5.5km/km~2,3～7km/km~2的地区占84%。相对高差150～250m的地区占60%以上。区域平均坡度15°～30°的地区占68%。地貌曝露面3.1～6km~2/km~2的地区占64.54%。给出了相对高差、地貌曝露面及土壤侵蚀模数区域分布的趋势面分析模型。通过聚类分析将研究区划分为二大类型组合区、八个亚区和十三个小区。论述了区内类型组合、环带镶嵌的地貌特点。

THE STATISTICAL FEATURES TREND SURFACE AND CLUSTER ANALYSIS OF THE GEOMORPHY IN THE LOESS REGION OF THE DRAINAGE AREA OF THE WUDING RIVER

Based on the field survey, measuring and sampling statistics on the contouring maps (1/50,000), this paper shows that the density of the gul-lies and valleys is mainly 3 to 7 km./km.~2, which is 84 per cent of thesamples; the relative height is-150 to 250m., 60% out of the samples;the slope angles are from 15°to 30°, 68% out of the samples. The geomor-phical exposure surface is 3.1 to 6km.~2/km.~2 which is 64.54 per cent ofthe total samples. The models of the trend surface and the cluster analysisare put forward. Finally according to the principles of the morpho-geneticaland practical utilization, 4 regions and 13 locations of the lands cape aredescribed in this paper.