The low-latitude western boundary current system in the North Pacific Ocean plays an important role in climate due to its huge transports of heat and water masses. Several previous studies have examined the interannual variation of Kuroshio at its origin and the Luzon Undercurrent (LUC) through numerical simulations or simulation-based assimilated data. However, due to the lack of continuous observation, the interannual variability of Kuroshio and LUC, especially in terms of the spatiotemporal features and underlying dynamic is unclear yet.
   During 2018–2020, a mooring array equipped with Acoustic Doppler Current Profilers (ADCP) were deployed in the Luzon Island by the Institute of Oceanology of CAS on the basis of a single mooring observing during 2010–2012. In this study, we aim to investigate the interannual variability of the LUC and Kuroshio using these ADCP measurements. Some interesting spatiotemporal features of the interannual variability of Kuroshio and LUC are found from these direct observations. A proxy of the upper-layer Kuroshio/LUC is proposed based on the measurements and key dynamic processes that determine the interannual variability of Kuroshio and LUC are investigated.
 

Western North Pacific, Western boundary currents, Interannual variations, Wind forcing, Observations