单流向法地形湿度指数尺度效应的不同地形区差异分析  

Scale Effect Analysis to Topographic Wetness Index Extracted by Single Flow Direction Algorithm in Different Terrain Area

作　　者：王海力[1] 韩光中[1] 谢贤建[1] 

机构地区：[1]内江师范学院地理与资源科学学院,四川内江641112

出　　处：《地理与地理信息科学》2016年第4期23-29,F0003,共8页Geography and Geo-Information Science

基　　金：国家自然科学基金项目(41401235);四川省教育厅基金项目(15ZB0275)

摘　　要：利用DEM提取地形湿度指数(Topographic Wetness Index,TWI),以满足既定地理模型构建,需考虑不同地形区TWI提取的尺度效应。该文根据实际应用中的DEM分辨率尺度,生成1m、2.5m、5m、10m、20m、30m分辨率尺度的6景DEM;利用单流向算法提取研究区TWI;通过定性和定量方法分析了在不同DEM分辨率尺度中,居民地、梯田、湖泊和自然地形区4种地形区域中TWI值分布特征。结果表明:不同地形区TWI的尺度效应差异较大;随着DEM尺度增大,TWI值域逐渐缩小,变异程度逐渐增强,反映地表形态变化的能力逐渐减小;当DEM尺度大于5m时,TWI基本不能反映人工地形区域;自然地形区的TWI变化规律与研究区整体TWI变化规律相当,居民地与梯田的TWI变化规律大致相同,湖泊区域的TWI变化相对稳定。Topographic Wetness Index（TWI）is extracted in Digital Elevation Model（DEM）.When extracts it for meeting the needs of geographic model building in established study area,it must consider the scale effect analysis to TWI extracting in different terrain area such as natural surface,residents,terraces,lakes,under the condition of different resolution scales of DEM.According to the DEM resolution scale used in the practical production,6kinds of different resolution scale DEMs include 1m,2.5m,5m,10 m,20m,30 mhave been made by adjusting the parameters of the grid cell during DEM production.This paper extracts TWI through the method of single flow direction based on above DEM data,the TWI characteristics distributing in the terrain area of residential land,terrace,lake and natural have been qualitatively and quantitatively analysed.The results show that the TWI scale effect is different in different terrain area.With the increase of DEM scale,the range of TWI gradually narrowed,variation degree gradually increased,the ability of responding to changes in surface morphology decreased.The TWI distribution character nearly can′t reflect the artificial terrain when DEM resolution greater than 5m.The TWI distribution character of each terrain area shows that the change regularity of TWI between natural terrain and the whole study area have the same characteristic,the change character of TWI in residential land is approximately the same as terrace,TWI change regularity in lake area is relatively stable.

关 键 词：地形湿度指数 DEM 不同地形区 尺度效应 单流向算法 

分 类 号：P208[天文地球—地图制图学与地理信息工程]