关键词: 高程基准; GNSS水准; 高程异常; EGM2008; 移去-恢复; 海面地形; 长江口;

Abstract: It is of great significance to establish a stable and reliable height datum on the offshore islands and reefs.At present, the GNSS leveling method is mainly used to transfer the elevation datum of offshore islands and reefs, but the accuracy is difficult to evaluate.We use the high-precision GNSS leveling data in the Changjiang estuary region to fit the distribution of abnormal height in the Changjiang estuary by different models methods, obtaining the abnormal height of the control points on the islands, which realizes the height transference of the islands in the Changjiang estuary.The example shows that the quadric surface fitting method based on the EGM2008 global gravity field model and the principle of “remove-recovery”is preferred in elevation transference in the Changjiang River Estuary.If the distribution of sea surface topography and the long-term tide level observation data are available, the synchronous water level method can also be used for height transference.

Key words: elevation datum; GNSS leveling; abnormal height; EGM2008; remove-recovery; sea surface topographic; Changjiang River Estuary;