河流宽度是河流动态过程研究和水文、水动力模型的关键参数之一.传统水文测站无法观测河宽的空间分布,而卫星遥感影像可以实现河宽的大范围观测.本文选取黄河上游唐乃亥水文站以上流域作为研究区,基于Sentinel-2遥感影像,采用Google Earth Engine大数据云计算平台和RivWidth方法提取河宽,并开发了一种新的河流连通性的构建方法,提高了RivWidth的运算效率,最终生成了 2019-2021年黄河源区10 m空间分辨率的逐月河流宽度数据(Monthly River Width Data,MRWD).结果表明,本文开发的河流连通性的构建方法使得RivWidth的运算效率提高了 24.7％.逐月河流宽度数据包括6.1 × 106个河流宽度估算值,覆盖了黄河源区2035 km的河流.与水文站点实测河宽和全球河流宽度数据河宽(Global River Widths from Landsast,GRWL)对比验证结果显示,本文新算法反演的逐月河流宽度数据的平均绝对值百分比误差、均方根误差和相对均方根误差分别为7.82％、1 1.62 m、8.84％.基于逐月河流宽度数据,本文发现黄河源区范围内大约有41％的河道窄于100 m,85％以上的河道宽度小于500 m,仅2％的河道宽度超过1000 m.本文生成的逐月河流宽度数据可为地表水资源管理提供重要参考依据.
An efficient river width extraction algorithm for analyzing the annual variation of the river width in the upper reaches of the Yellow River
River width is one of the key parameters for studying river dynamic processes and hydrological and hydrodynamic models.Compared with traditional hydrological stations,satellite images can achieve large-scale observations of river width.Based on Sentinel-2 imagery,Google Earth Engine(GEE)and RivWidth tool,a new river connectivity construction method was developed to improve the computational efficiency of RivWidth tool for river width extraction,and the monthly river width dataset(MRWD)with a 10-m spatial resolution from 2019 to 2021 in the upper reaches of the Yellow River was generated by the improved algorithm.The results show that the river connectivity construction method developed in this study(referred to as the connection method)improves the computing efficiency of RivWidth tool by 24.7％.The comparison and verification results with the in-situ river width and GRWL(Global River Widths from Landsat)river width show that the mean absolute percentage error(MAPE),root mean square error(RMSE)and relative root mean square error(RRMSE)of MRWD are respectively 7.82％,11.62 m,and 8.84％.The MRWD includes 6.1 × 106 river width estimations,covering 2035 km of rivers in the upper reaches of the Yellow River,of which 41％are narrower than 100 m,more than 85％are less than 500 m,and 2％are more than 1000 m.The MRWD generated in this study can provide an important reference for surface water resources management.
Sentinel-2GEEthe upper reaches of Yellow Riverriver widthRivWidth
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NSTL
万方数据
