Abstract Hydrodynamic (HD) modelling in data sparse region represents a challenge due to poor hydrological and topographic data availability. Recently, remote sensing techniques offer additional data that may help to improve the reliability and accuracy of such analysis. In this study, an attempt has been made to investigate the potential and added value of altimeter measurements for multi-site validation of the HD model and constructed rating curves (RCs) in a sparsely gauged Brahmaputra River, India. The HD model (MIKE 11) was developed for a Brahmaputra River stretch of 135 km, between Tezpur and Guwahati, where 4 ground-tracks of the SARAL/AltiKa (the first Ka band altimeter mission) cross the river. The Nash Sutcliffe efficiency (NSE) between HD model based water level and in-situ water level during calibration (January-October 2013) and validation (January-March 2014) was found to be 0.93 and 0.79 respectively. Calibrated and validated HD model was used to simulate water level and build rating curves at virtual stations. The bias correction (7.2 cm to 9.5 cm) was applied to the altimetry measurements before comparison with the modelled water levels. The root mean square error (RMSE) ranging between 15 cm and 42 cm was observed between the modelled and altimetry-derived water level at all the virtual stations, indicating the potential of satellite altimetry for multi-site validation of the HD model (inline with previous studies) and validation of the constructed RCs. The availability of RCs at virtual stations allows the expansion of the gauging network along the Brahmaputra River, thus enabling the estimation of the discharge at additional locations and the potential evaluation of the contributions of lateral tributaries could be evaluated in future work.

中文翻译：

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SARAL/AltiKa 高度计测量值在多站点水动力模型验证和额定曲线估计中的使用：在布拉马普特拉河中的应用

摘要 由于水文和地形数据的可用性较差，数据稀疏区域中的流体动力学 (HD) 建模是一项挑战。最近，遥感技术提供了额外的数据，可能有助于提高此类分析的可靠性和准确性。在这项研究中，已尝试研究高度计测量的潜力和附加值，用于在印度布拉马普特拉河测量稀少的布拉马普特拉河中多地点验证 HD 模型和构建的评级曲线 (RC)。HD 模型 (MIKE 11) 是为 135 公里长的雅鲁藏布江河段开发的，位于 Tezpur 和 Guwahati 之间，SARAL/AltiKa（第一个 Ka 波段高度计任务）的 4 条地面轨道穿过河流。在校准（2013 年 1 月至 10 月）和验证（2014 年 1 月至 3 月）期间，基于 HD 模型的水位与原位水位之间的 Nash Sutcliffe 效率 (NSE) 分别为 0.93 和 0.79。校准和验证的 HD 模型用于模拟水位并在虚拟站建立评级曲线。在与模拟水位进行比较之前，将偏差校正（7.2 厘米至 9.5 厘米）应用于高度测量。在所有虚拟站的模拟水位和测高得出的水位之间观察到范围在 15 cm 和 42 cm 之间的均方根误差 (RMSE)，表明卫星测高在 HD 模型的多站点验证中具有潜力（与先前的研究）和构建的 RC 的验证。