染色法测量坡面流流速的最佳测流区长度研究  

Study on Optimal Length for Measuring Velocity of Overland Flow with Dye Tracing

作　　者：罗榕婷[1] 张光辉[1,2] 沈瑞昌[1] 曹颖[1] 

机构地区：[1]北京师范大学地理学与遥感科学学院,北京100875 [2]北京师范大学地表过程与资源生态国家重点实验室,北京100875

出　　处：《水文》2010年第3期5-9,共5页Journal of China Hydrology

基　　金：国家重点基础研究发展规划项目(2007CB407204);地表过程与资源生态国家重点实验室自主科研课题(2008-ZZ-04)

摘　　要：染色法是测定坡面流流速最常用的方法,但对测流区长度的选择没有统一标准。统一测流区长度不仅能减少流速测定误差,还能提高不同试验间的可比性。本文采用室内变坡水槽试验,用染色法测量表面最大流速并计算平均流速时,选择6个常见测流区长度,以流量法计算的平均流速为参照值,选取5个统计参数(RRMSE、RE、NSE、R2、MAE)作为评价指标,将不同测流区长度下染色法与流量法所获得的平均流速进行比较,分析染色法测量坡面流流速的最佳距离。研究结果表明:当测流区长度为2m和3m时,RRMSE都较小;在2m处,RE、MAE达到最小,NSE、R2最接近1,此时染色法测定的流速与流量法计算的流速最为接近。因此,用染色剂法测量坡面流速度的最佳距离应选在2m。The velocity of overland flow has been conventionally measured by using dye tracing.However,there is no uniform selective criteria for optimal length of a dye cloud across.Defining the standard of length does not only reduce measurement errors of velocity,but also improves comparability among different experiments.Generally,motion of the dye front reflects the surface flow speed,and a correction factor must be employed to derive a value for the mean speed.Experiments were performed in a hydraulic flume with varied slopes,and six common lengths for measuring velocity of overland flow with tracers were chosen.Using the mean velocity calculated by the volumetric flow relation for reference and five statistical parameters（RRMSE,RE,NSE,R2,MAE） as evaluation,analysis of the best distance is derived after comparison of the values measured using tracers with speed reference.The results indicated that：（1） when the length is 2m or 3m,two RRMSE are both less than others;（2） when the length is 2m,RE and MAE touch their minimum values respectively,and NSE and R2 get closest to one.In other words,the velocity measured with tracers is highly correlated with speed reference at this length.Therefore,the length of 2m is proved optimal for measuring velocity of overland flow using dye tracing.

关 键 词：染色法 流速 测定距离 坡面流 流量法 

分 类 号：P332.4[天文地球—水文科学]