资源环境科技发展态势分析平台

Satellite radar altimetry has become an important data source supplementing in‐situ water level. For practical reasons, a radar altimeter can only record reflected echoes within its range window. Therefore, water surface elevation must fall within the range window. To this end, the Sentinel‐3 radar altimetry mission is configured with a new tracking function (i.e. open‐loop) to position its range window based on an on‐board a‐priori elevation of ground targets. We found that Sentinel‐3 is unable to observe recently built reservoirs due to the incorrect on‐board elevations. To overcome this issue, four approaches are proposed to improve the a‐priori elevation for inland water bodies, particularly reservoirs. These approaches can significantly increase data availability of Sentinel‐3 over reservoirs and can be used to prepare the on‐board elevation of reservoirs and lakes for future missions such as Sentinel‐6, Sentinel‐3C/‐3D, as well as the Surface Water Ocean Topography mission (SWOT).