Small water parcels, which are characterized by a low salinity and high dissolved oxygen (DO) are observed by Seaglider in the main thermocline (26.0–27.0 σ_θ) south of the Kuroshio Extension (KE), have horizontal and vertical scales of a few tens of kilometers and a few tens of meters, respectively. Water mass analyses revealed larger negative salinity anomalies (<− 0.05) and positive DO anomalies (> 15 μmol kg⁻¹) than those of the surrounding water. The characteristics are similar to those of water mass with low salinity and high DO in the subpolar Northwestern Pacific Ocean. Additionally, higher DO anomaly water parcels appear in the upper layer (< 26.7 σ_θ) while low salinity parcels appear in the lower layer (> 26.7 σ_θ). Oxygen consumption rates from the apparent oxygen utility suggest that the small water parcels consume less oxygen than the surrounding water, implying that they migrate in a shorter time across the KE after subduction and their characteristics may reflect the sea surface temperature, salinity, and DO in the subduction region. Similar small water parcels represented by high-resolution numerical simulations indicate that they pass through the KE in 1 month. The simulations support the oxygen consumption rate from the Seaglider observations. The existence of a fast process for water mass migration via meso- and submesoscale subduction processes across the KE affects the amount, subduction, and exchange process of water mass. Our study indicates that a small water mass contributes to the exchange process across the KE rapidly, which had not been identified in previous studies. Consequently, detailed observations using multiple Seagliders should capture detailed spatial and temporal variability of the water mass exchange process.

小水包裹，其特征在于低的盐度和高溶解氧（DO）是通过Seaglider在主跃层观察（26.0-27.0σ _θ黑潮扩展（KE）的）南方，有几个的水平和垂直尺度几十公里和几十米。水质分析显示，负盐度异常（<-0.05）和正DO异常（> 15μmolkg ^-1）比周围水更大。该特征与西北极极地极低盐度和高溶解氧的水团相似。此外，较高的DO水异常包裹出现在上部层（<26.7σ _θ），而低盐度包裹出现下层中（> 26.7σ _θ）。表观耗氧量的耗氧率表明，小水域的氧气消耗比周围水少，这意味着它们在俯冲后在KE内迁移的时间较短，其特征可能反映了海面温度，盐度和溶解氧。俯冲区域。高分辨率数值模拟表示的类似小水块表明它们在1个月内通过了KE。模拟结果支持了Seaglider观测的耗氧率。通过中尺度和亚中尺度的俯冲过程，水团快速迁移过程的存在会影响水团的数量，俯冲和交换过程。我们的研究表明，少量水会迅速促进整个KE的交换过程，在先前的研究中尚未发现。因此，使用多个滑翔机进行的详细观测应捕获水质交换过程的详细时空变化。