Ocean current is one of the major drivers of water mass, energy, and biogeochemical cycles in the global ocean–atmosphere boundary layer and also a key variable in the formation of extreme climate events (e.g., El Niño). Direct measurement of the global ocean surface current is of great scientific interest and application value for understanding multiscale ocean dynamics, air-sea interaction, ocean mass and energy balance, and ocean carbon budget, as well as their variabilities under climate change. This paper reviews the state-of-the-art developments of ocean dynamics and technology on the observation of multiscale ocean circulation and related scientific frontiers. Presently, measurements of global ocean surface currents, which are mainly geostrophically derived from satellite altimeter data, are only available to resolve quasi-geostrophic current at large- to meso-scale in the off-equatorial open ocean. This becomes a bottleneck impeding the application and the development of ocean circulation dynamics. With the ambition of breaking the bottleneck, Ocean Surface Current multiscale Observation Mission (OSCOM) will launch a satellite equipped with a Doppler Scatterometer to directly measure ocean surface currents for the first time with a very high horizontal resolution of 5–10 km and a 3-day global coverage. Through carrying a Surface Temperature Infrared Radiometer and a Surface Temperature Microwave Radiometer, the OSCOM satellite is supposed to have the capability of observing ocean surface current, ocean surface vector wind, and sea surface temperature simultaneously. With a cutting-edge design, OSCOM will provide an in-depth picture of non-equilibrium ocean state and air-sea interaction from mesoscale to submesoscale, and helps to construct the fine structure of deep ocean current through a combination with Array for Real-time Geostrophic Oceanography profiling. Those direct measurements and derived dynamic parameters will further facilitate analyses of ocean carbon budget and ocean biogeochemical cycle, and provide a novel and improved pathway to data assimilation, coupling of General Circulation Models, and the Earth System Modelling for ocean prediction and climate change.

洋流是全球海洋–大气边界层中水量，能量和生物地球化学循环的主要驱动力之一，也是形成极端气候事件（例如厄尔尼诺现象）的关键变量。对于了解多尺度海洋动力学，海-气相互作用，海洋质量和能量平衡，海洋碳收支及其在气候变化下的变化性，直接测量全球海洋表面流具有重大的科学兴趣和应用价值。本文从多尺度海洋环流和相关科学前沿的观测出发，回顾了海洋动力学和技术的最新发展。目前，主要是从卫星高度计数据的地转学角度出发，对全球海面洋流进行的测量，仅可用于在赤道外的公海中以大尺度到中观尺度解析准地转流。这成为阻碍海洋环流动力学应用和发展的瓶颈。为了突破瓶颈，海洋表面多尺度观测团（OSCOM）将发射配备多普勒散射仪的卫星，这是首次以5–10 km的极高水平分辨率和3的水平分辨率直接测量海洋表面流。天的全球覆盖率。通过携带表面温度红外辐射仪和表面温度微波辐射仪，OSCOM卫星应具有同时观测海面电流，海面矢量风和海面温度的能力。尖端的设计，OSCOM将提供从中尺度到亚中尺度的非平衡海洋状态和海-气相互作用的深入图景，并通过与Array结合用于实时地转海洋学图谱分析，帮助构建深海流的精细结构。这些直接测量和导出的动态参数将进一步促进对海洋碳收支和海洋生物地球化学循环的分析，并为数据同化，一般环流模型的耦合以及用于海洋预测和气候变化的地球系统建模提供新颖且改进的途径。