拉萨河流域河宽与地形结构因子相互关系分析

摘要

利用Google Earth遥感影像,测量了拉萨河流域451个局部河段的河流水面宽度,得出了10个主要河段的平均河宽.研究中,分别点绘了10个主要河段的平均河宽与5种地形结构因子(河流纵比降、弯曲度、凹度、河流上游集水面积、流域平均坡度)的相关图,采用线性函数、指数函数、对数函数以及幂函数4种函数对其进行相关性分析.结果发现,在5种因子中,河流水面宽度与上游集水面积相关性最好,当用线性函数拟合时确定性系数达到了0.81;河流的纵比降与河宽的相关性也较好,当采用指数函数与幂函数拟合时,两者的确定性系数均为0.76.研究探讨拉萨河流域河宽和地形结构因子的相互关系对认识青藏高原河流地貌特征规律以及提高无资料流域河流流量和总水量预测的能力等均有重要意义.%The average river flow width of ten main river segments in Lhasa River drainage basin were obtained with the help of remote sensing data of Google Earth after gauging the river width of 451 reaches.On this premise,the correlation between river flow width and five topographic factors,inclusive of river's longitudinal slope,river's tor-tuosity,river's concavity,upstream catchment area and catchment average slope,were plotted with four different functions:linear function,exponential function,logarithmic function,and power function.Results implied that,a-mong the five factors,upstream catchment area is of the largest correlation with river flow width with the coefficient of certainty amounting to 0.81 when fitted by linear function;longitudinal slope of river also has a remarkable im-pact on river flow width,with the coefficient of certainty reaching 0.76 fitted by power function and exponential function.Researching the correlation between river flow width and topographic structure factors in Lhasa River drainage basin would be of crucial significance for us to understanding the river geomorphology in Qinghai-Tibet Plateau and improving our ability of estimating flow rate and total flow amount in ungauged basins.