Comparing measurements of absolute sea level by satellite altimetry and relative sea level by a tide gauge can reveal errors in either measurement system. Combining the measurements can determine vertical land motion (VLM) at the tide gauge. We here discuss ten case studies in which a tide gauge has likely experienced a small (\(\le 10\) cm), discontinuous offset in the vertical, suggesting inadvertent loss of reference-level stability. Proper interpretation of offsets is helped if independent VLM measurements from nearby geodetic stations are available. In two cases, earthquake-induced VLM cannot be ruled out, although it appears unlikely. Offsets as small as 1–2 cm can be detected when both altimeter and tide gauge successfully observe the same ocean signal. This is most likely to occur for tide gauges located on small, open-ocean islands. Tide gauges near large land masses are typically more challenging owing to inadequacies of satellite altimetry near land and to differences between coastal and open-ocean sea levels. The case studies highlight the utility of satellite altimetry for tide-gauge quality control.

比较卫星测高仪测量的绝对海平面和潮汐计测量的相对海平面可以揭示任一测量系统的误差。结合测量结果可以确定潮汐计处的垂直陆地运动 (VLM)。我们在这里讨论十个案例研究，其中验潮仪可能 在垂直方向上经历了小（ \（\le 10\）厘米）不连续的偏移，这表明参考水平稳定性的无意损失。如果可以使用附近大地测量站的独立 VLM 测量值，则有助于正确解释偏移量。在两种情况下，不能排除地震引起的 VLM，尽管这似乎不太可能。当高度计和潮汐计成功观测到相同的海洋信号时，可以检测到小至 1-2 厘米的偏移。位于公海小岛上的验潮仪最有可能发生这种情况。由于陆地附近卫星测高的不足以及沿海和公海海平面之间的差异，大片陆地附近的潮汐测量通常更具挑战性。这些案例研究强调了卫星测高在潮汐测量质量控制中的实用性。