Prospects for calibrating rainfall‐runoff models using satellite observations of river hydraulic variables as surrogates for in situ river discharge measurements
Prospects for calibrating rainfall‐runoff models using satellite observations of river hydraulic variables as surrogates for in situ river discharge measurements
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DOI：
10.1002/hyp.8301
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发表时间：
2012-03
影响因子：
3.2
通讯作者：
Wenchao Sun;H. Ishidaira;S. Bastola
中科院分区：
文献类型：
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作者：
Wenchao Sun;H. Ishidaira;S. Bastola
校准的需要限制了降雨径流（RR）模型在未计量流域中的直接应用。在本文中，我们提出了一个使用可通过遥感观测的河流水力变量（河流宽度或水面高程）校准 RR 模型的概念框架。通过将RR模型与站点水力几何相结合，利用幂函数描述流域出口处的断面水力关系，模拟的河流宽度或水面高程成为集成模型的输出。然后，校准的目标转向最小化液压变量的模拟值和卫星测量值之间的差异。相应地，标定过程是通过同时调整RR模型和幂函数参数来进行的。根据卫星观测特点，选择水文模型（HYMOD）RR模型和非支配排序遗传算法II（NSGAII）多目标优化方案。老挝西南部湄公河流域的巴色测量站进行了概念验证实验。在设计的平均和低卫星观测频率下，使用巴色测量站的河流宽度或水面高程的地面测量值，通过校准获得了具有可接受精度的流量估计。从实验结果来看，发现较高的观测频率更有利于做出更可靠的估计。采用地面测量和卫星观测可能存在的误差作为校准数据，最大不确定度小于巴色站日平均流量的20%。该概念框架可以为改进大型未计量流域的河流流量估算提供新工具。版权所有 © 2011 约翰·威利父子有限公司
The need for calibration limits the direct application of rainfall‐runoff (RR) models in ungauged basins. In this paper, we present a conceptual framework for calibrating RR models using river hydraulic variables (river width or water surface elevation) that are observable by remote sensing. By integrating a RR model with at‐a‐station hydraulic geometry, using power functions to describe the cross‐sectional hydraulic relationship at the basin outlet, the simulated river width or water surface elevation become the output of the integrated model. The objective of the calibration is then shifted to minimizing the difference between the simulated values and the satellite measurements of the hydraulic variables. Correspondingly, the calibration process is carried out by tuning the RR model and power function parameters simultaneously. The HYdrological MODel (HYMOD) RR model and Nondominated Sorting Genetic Algorithm II (NSGAII) multi‐objective optimization scheme were selected based on the characteristics of satellite observations. A proof‐of‐concept experiment was carried out for the Pakse gauging station in the Mekong Basin, southwest Laos. Discharge estimates with acceptable accuracy were obtained by calibration, using ground measurements of either river width or water surface elevation at the Pakse gauging station, under designed average and low satellite observation frequencies. From the results of the experiment, a higher observational frequency was found to be preferable for making more reliable estimations. Using ground measurements with the possible error of satellite observations as calibration data, the maximum uncertainty was less than 20% of the mean daily discharge at Pakse station. This conceptual framework can provide a new tool for improving river discharge estimation in large ungauged basins. Copyright © 2011 John Wiley & Sons, Ltd.