基于四种分辨率DEM的侵蚀模型地形因子差异分析  

GEOMORPHIC FACTORS IN DEM-BASED SOIL EROSION MODELS AS AFFECTED BY RESOLUTION

作　　者：郭春香[1,2] 梁音[1] 曹龙熹[1] 

机构地区：[1]中国科学院土壤环境与污染修复重点实验室(南京土壤研究所),南京210008 [2]中国科学院大学,北京100049

出　　处：《土壤学报》2014年第3期482-489,共8页Acta Pedologica Sinica

基　　金：国家科技支撑计划项目(2011BAD31B04-2);水利部长江委重点项目(花岗岩地区马尾松林地水土流失规律试验研究);中国科学院战略性先导科技专项(122011151432016)资助

摘　　要：通过提取江西省兴国县潋水河流域10m、25m、50m和100m四种分辨率数字高程模型（DEM，DigitalElevationModel）的坡度、坡长因子，在GIS数字地形分析和数理分析等方法支持下，研究不同分辨率DEM计算坡度坡长组合因子（Ls）的精度差异。结果表明：（1）基于4种分辨率DEM提取的坡度结果存在明显差异，随分辨率的降低，坡度整体变缓，DEM精度越低，对地形的概括作用越大，100m分辨率DEM平均坡度降为10m分辨率DEM平均坡度的45．04％。（2）流域坡长以0～80m的短坡为主，随着分辨率的降低，地面坡长明显整体延伸。（3）不同分辨率DEM计算的Ls因子平均值变化范围为6．10—7．10，坡度和坡长的组合消弱了单一坡度和坡长的影响，随着地形起伏程度增大，在Ls因子计算过程中，坡度的主导作用越来越弱，坡长的主导作用越来越强。Gradients and lengths of the slopes in the Lianshui River Basin,Xingguo County,Jiangxi Province were extracted using DEMs different in resolution,i, e. lOm,25m,50m and lOOm,and analyzed for difference in accuracy differ- ence between the DEMs in calculating the combined gradient and length,using the GIS digital terrain analysis method and the mathematical analysis method. Results show that 1 ） significant differences exist between slope gradients obtained by DEMs different in resolution,indicating that the gradient decreases with declining resolution and that the lower the accura- cy,the greater the generalized effect on terrain information; and that the mean slope gradient obtained by DEM 100m in resolution is only 45.04% of that by DEM 10m in resolution;. 2） the slopes in the valley vary in length mainly in the range of 0 ~ 80m and their lengths elongate with declining resolution; and 3 ） the mean LS factor values obtained by the DEMs regardless of resolution vary in the range from 6. 10 to 7.10 ; the combination of slope gradient and slope length fac- tors reduces the effects of single slope gradient or single slope length factor; and as the topographic fluctuation increases in extent,the dominating role in LS factor shifts from slope gradient to slope length.

关 键 词：DEM 地形分析 地形因子 坡度 坡长 

分 类 号：S157[农业科学—土壤学]