琉球海流是西北太平洋一支重要的西边界流，不仅在全球水量、热量和物质循环中起重要作用，而且还通过入侵东海对东海的海洋动力环境产生重要影响。目前对琉球海流在冲绳岛以北的下游海区的时空变化已经基本清楚，但琉球海流上游海区还几乎是一个观测的空白区域。本项目计划通过国际合作，在琉球海流上游海区进行为期2年的锚系阵列观测，并结合历史调查资料、Argo浮标资料、卫星遥感资料和数值模式研究，分析琉球海流在其上游海区的时空变化, 了解琉球海流的形成区域和过程,力争阐明琉球海流起源的动力机制；同时分析研究琉球海流通过庆良间水道等重要通道对东海入侵的时空变化，阐明琉球海流入侵东海的动力机制；评价琉球海流的水量和热量在黑潮中所起的作用，分析琉球海流入侵对东海海洋动力环境的影响。本项目的顺利实施对北太平洋西边界流的研究具有重要的科学意义，并且，对我国东海的海洋环境、渔业及海军军事活动都有较大的现实意义。

The Ryukyu Current is an important western boundary current in the North Pacific. It not only plays an important role in the global circulation of water, heat and materials, but also deeply impacts the dynamic environment in the East China Sea by directly intruding into the East China Sea. In the downstream region north of Okinawa Island, the temporal and spatial variations of the Ryukyu Current have been well studied; however, in the upstream area current variations remain unknown due to the lack of observations. To begin filling this knowledge gap, we will, with international cooperation, conduct a 2-year long mooring-array study. Simultaneously, we will also analyze data from historical investigations, ARGO data, satellite remote sensing data, and numerical simulations. In addition to quantifying the temporal and spatial variations of the Ryukyu Current in the upstream area, we will attempt to clarify its origin and formation mechanisms. Moreover, we will study the following: the temporal and spatial variation of the current's intrusion into the East China Sea through important channels along the Ryukyu Island chain (such as the Kerama Gap); the dynamic mechanisms of the intrusion; and the intrusion's influence on the environment in the East China Sea. Finally, we will evaluate the effect of the Ryuku Current's water and heat on the Kuroshio and the East China Sea. This project will significantly impact the research on the western boundary current in the Northwestern Pacific. Furthermore, our research has practical importance in terms of the ocean environment, fisheries, and naval military activities in the East China Sea.