This paper reviews the recent progress in our estimation of ocean dynamic topography and the derived surface geostrophic currents, mainly based on multiple nadir radar altimeter missions. These altimetric observations provide the cornerstone of our ocean circulation observing system from space. The largest signal in sea surface topography is from the mean surface dominated by the marine geoid, and we will discuss recent progress in observing the mean ocean circulation from altimetry, once the geoid and other corrections have been estimated and removed. We then address the recent advances in our observations of the large-scale and mesoscale ocean circulation from space, and the particular challenges and opportunities for new observations in the polar regions. The active research in the ocean barotropic tides and internal tidal circulation is also presented. The paper also addresses how our networks of global multi-satellite and in situ observations are being combined and assimilated to characterize the four-dimensional ocean circulation, for climate research and ocean forecasting systems. For the future of ocean circulation from space, the need for continuity of our current observing system is crucial, and we discuss the exciting enhancement to come with global wide-swath altimetry, the extension into the coastal and high-latitude regions, and proposals for direct total surface current satellites in the 2030 period.

本文综述了我们在估计海洋动态地形和推导的表面地转流方面的最新进展，主要基于多次天底雷达高度计任务。这些测高观测为我们的太空海洋环流观测系统提供了基石。海面地形中最大的信号来自海洋大地水准面主导的平均表面，一旦大地水准面和其他修正被估计和移除，我们将讨论通过测高法观察平均海洋环流的最新进展。然后，我们讨论了我们从太空观测大尺度和中尺度海洋环流的最新进展，以及极地地区新观测的特殊挑战和机遇。还介绍了在海洋正压潮汐和内部潮汐环流方面的积极研究。本文还讨论了我们的全球多卫星网络和原位观测如何结合和同化以表征四维海洋环流，用于气候研究和海洋预报系统。对于来自太空的海洋环流的未来，我们当前观测系统的连续性需求至关重要，我们讨论了全球宽测带测高带来的令人兴奋的改进、向沿海和高纬度地区的扩展，以及关于2030 年直接总表面流卫星。本文还讨论了我们的全球多卫星网络和原位观测如何结合和同化以表征四维海洋环流，用于气候研究和海洋预报系统。对于来自太空的海洋环流的未来，我们当前观测系统的连续性需求至关重要，我们讨论了全球宽测带测高带来的令人兴奋的改进、向沿海和高纬度地区的扩展，以及关于2030 年直接总表面流卫星。本文还讨论了我们的全球多卫星网络和原位观测如何结合和同化以表征四维海洋环流，用于气候研究和海洋预报系统。对于来自太空的海洋环流的未来，我们当前观测系统的连续性需求至关重要，我们讨论了全球宽测带测高带来的令人兴奋的改进、向沿海和高纬度地区的扩展，以及关于2030 年直接总表面流卫星。