Using SODA oceanic reanalysis data, the subduction rate and low potential vorticity (PV) water masses in the North Pacific are investigated from January 1870 to December 2008. A new low PV water mass with a large subduction rate is found near‐equatorial North Pacific, which is named as the near‐equatorial North Pacific low PV water mass (NELPVW), and it is the only one low PV water mass in North Pacific that appears an increasing trend under global warming. Among all the low PV water masses in North Pacific, only Eastern Subtropical Mode Water (EMW) and NELPVW can migrate to the equatorial Pacific and effect subsurface oceanic temperature (SOT) there. Further research shows that the subducted low PV water mass in EMW generation region can migrate to equatorial Pacific through two transport paths, which are called the Western‐EMW path and the Central‐EMW path. The analysis of Lagrange tracking shows that EMW can migrate and bring SOT anomaly to equatorial Pacific along these paths in 7 years and lead to the almost precisely opposite distributions of equatorial Pacific SOT anomaly between the strong and weak EMW subduction years, while it takes the newly discovered NELPVW less than 3 years to reach the equatorial Pacific along the Western‐NELPVW path or the Eastern‐NELPVW path after subduction. The distributions of equatorial Pacific SOT anomaly in the strong and weak NELPVW subduction years are approximately reverse too. The actual distribution of the equatorial Pacific SOT is affected by these two low PV water masses at the same time.

中文翻译：

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近赤道北太平洋低PV水特征及其对赤道表层海洋的可能影响

利用SODA海洋再分析数据，研究了1870年1月至2008年12月北太平洋的俯冲率和低潜在涡度（PV）水团。在赤道北太平洋附近发现了俯冲率大的新的低PV水团，它被称为近赤道北太平洋低PV水团（NELPVW），它是北太平洋唯一在全球变暖下呈上升趋势的低PV水团。在北太平洋的所有低PV水量中，只有东亚热带模式水（EMW）和NELPVW可以迁移到赤道太平洋并影响那里的地下海洋温度（SOT）。进一步的研究表明，EMW产生区俯冲的低PV水量可以通过两条输送路径迁移到赤道太平洋，分别称为Western-EMW路径和Central-EMW路径。拉格朗日跟踪的分析表明，EMW可以在7年内沿着这些路径迁移并将SOT异常带到赤道太平洋，并导致强和弱EMW俯冲年之间赤道太平洋SOT异常的分布正好相反，而新的变化则需要俯冲后不到3年的时间才发现NELPVW沿西NELPVW路径或东NELPVW路径到达赤道太平洋。NELPVW俯冲强弱年份的赤道太平洋SOT异常分布也大致相反。赤道太平洋SOT的实际分布同时受到这两个低PV水团的影响。拉格朗日跟踪的分析表明，EMW可以在7年内沿着这些路径迁移并将SOT异常带到赤道太平洋，并导致强和弱EMW俯冲年之间赤道太平洋SOT异常的分布正好相反，而新的变化则需要俯冲后不到3年的时间才发现NELPVW到达西NELPVW路径或东NELPVW路径的赤道太平洋。NELPVW俯冲强弱年份的赤道太平洋SOT异常分布也大致相反。赤道太平洋SOT的实际分布同时受到这两个低PV水团的影响。拉格朗日跟踪的分析表明，EMW可以在7年内沿着这些路径迁移并将SOT异常带到赤道太平洋，并导致强和弱EMW俯冲年之间赤道太平洋SOT异常的分布正好相反，而新的变化则需要俯冲后不到3年的时间才发现NELPVW到达西NELPVW路径或东NELPVW路径的赤道太平洋。NELPVW俯冲强弱年份的赤道太平洋SOT异常分布也大致相反。赤道太平洋SOT的实际分布同时受到这两个低PV水团的影响。