Abstract We evaluate different techniques that rebuild reservoir bathymetry by combining multi-satellite imagery of surface water elevation and extent. Digital elevation models (DEMs) are processed in two distinct ways in order to determine 3-D reservoir bathymetry. They are defined as (a) linear extrapolation and (b) linear interpolation. The first one linearly extrapolates the land slope, defining the bottom as the intersection of all extrapolated lines. The second linearly interpolates the uppermost and lowermost pixels of the reservoir's main river, repeating the process for all other tributaries. A visible bathymetry, resulting from the combination of radar altimetry and water extent masks, can be coupled with the DEM, improving the accuracy of techniques (a) and (b). Envisat- and Altika-based altimetric time series is combined to a Landsat-based water extent database over the 2002–2016 period in order to generate the visible bathymetry, and topography is derived from the 3-arcsec HydroSHEDS DEM. Fourteen 3-D bathymetries derived from the combination of these techniques and datasets, plus the inclusion of upstream and downstream riverbed elevations, are evaluated over Lake Mead. Accuracy is measured using ground observations, and show that metrics improve as a function of added data requirement and processing. Best bathymetry estimates are obtained when the visible bathymetry, linear extrapolation technique and riverbed elevation are combined. Water storage variability is also evaluated and shows that best results are derived from the aforementioned combination. This study contributes to our understanding and representation of reservoir water impoundment impacts on the hydrological cycle.

中文翻译：

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从多卫星数据集推导出三维水库测深

摘要 我们评估了通过结合地表水高程和范围的多卫星图像重建水库测深的不同技术。数字高程模型 (DEM) 以两种不同的方式进行处理，以确定 3-D 储层测深。它们被定义为 (a) 线性外推和 (b) 线性内插。第一个线性外推陆地坡度，将底部定义为所有外推线的交点。第二个线性插值水库主要河流的最上面和最下面的像素，对所有其他支流重复该过程。由雷达测高和水深面罩组合产生的可见水深测量可以与 DEM 结合使用，从而提高技术 (a) 和 (b) 的准确性。在 2002-2016 年期间，基于 Envisat 和 Altika 的高度时间序列与基于 Landsat 的水域范围数据库相结合，以生成可见水深测量，地形来自 3 弧秒 HydroSHEDS DEM。在米德湖上评估了从这些技术和数据集的组合以及上游和下游河床高程的组合中得出的 14 个 3-D 水深测量。准确性是使用地面观测来衡量的，并表明指标会随着数据需求和处理的增加而改进。当可见水深、线性外推技术和河床高程相结合时，可以获得最佳水深估计。还评估了储水可变性，并表明最好的结果来自上述组合。