基于最优尺度下的黄土高原区小流域密度及分形规律  

Density and Fractal Characteristics of Small Watershed in East Gansu Based on Optimal Scale

作　　者：王泽远 马良哲 杨飞翔 Wang Zeyuan;Ma Liangzhe;Yang Feixiang(Shaanxi Construction and Land Survey Planning and Design Institute Co.,Ltd.,Xi'an 710075,Shaanxi;Central and Southern Bureau of China Metallurgical Geology Bureau,Wuhan 430034,Hubei)

机构地区：[1]陕西地建土地勘测规划设计院有限责任公司,陕西西安710075 [2]中国冶金地质总局中南局,湖北武汉430034

出　　处：《陕西水利》2022年第1期6-10,共5页Shaanxi Water Resources

基　　金：陕西省土地工程建设集团有限责任公司内部科研项目“黄土高原区黄土非饱和带水汽运移规律研究”(DJNY2021-11)。

摘　　要：考虑尺度效应产生地表信息量表达的差异性,基于GIS与均值变点法对15个常用DEM模型尺度进行分析,得出表达陇东地区小流域密度与分形的最优尺度为90 m,汇流累积量阈值为500。以此为基础,分别使用2000年、2009年、2019年最优尺度下的DEM提取流域沟道信息,计算密度及分形分维值,并分析其时空变化规律,得出:20年间,沟道密度逐年增长13%,中游沟道密度值最高,分形维数随年份持续增加,全流域增加4.5%,流域分形值在1.3~1.4,沟道密度值在7~9之间的二级支沟数量最多,分布密度在0.6以上,且沟道密度与分形分维值呈现正相关性,说明流域沟道结构的复杂程度与疏密程度是相一致的。该结论可为陇东小流域演化发育特征的研究提供可靠依据。Considering the difference of surface information expression caused by scale effect,15 common DEM model scales are analyzed based on GIS and mean change point method.The results show that the optimal scale to express the density and fractal of small watershed in East Gansu is 90m,and the threshold value of confluence accumulation is 500.On this basis,DEM of 2000,2009 and 2019 were used to extract channel information,calculate density and fractal dimension,and analyze their temporal and spatial changes.The results show that:in the past 20 years,the channel density has increased by 13%year by year,and the density of the middle reaches is the highest.The fractal dimension continues to increase with the year,and the whole basin increases by 4.5%.The fractal value of the basin is(1.3~1.4).The number of secondary branch ditches with channel density between(7~9)is the largest,and the distribution density is more than 0.6.And there is a positive correlation between channel density and fractal dimension,which indicates that the complexity of channel structure is consistent with the density.This conclusion provides a reliable basis for the study of the evolution and development characteristics of Longdong small watershed.

关 键 词：尺度效应 形态演化 分形分维 沟道密度 小流域 

分 类 号：X141[环境科学与工程—环境科学]