Previous studies have suggested that global ocean circulation would be significantly changed under global warming, while the change of North Equatorial Countercurrent (NECC) and its mechanisms are still unclear. Here, we investigate the location and intensity changes of NECC under global warming based on CESM1 high-resolution long-term simulations from the perspective of the Inter-Tropical Convergence Zone (ITCZ), considering the close connection between NECC and ITCZ and well-established changes of ITCZ. It is found that the annual-mean NECC shifts equatorward of 0.39° and weakens by 21.71% in the RCP8.5 scenario at the end of 21st century. The NECC change is seasonally dependent, with maximum shift and weakening during spring, consistent with the changes of ITCZ. Both the location and intensity changes of ITCZ are important in the NECC changes, especially for spring. The weakening and equatorward shift of ITCZ contributes almost equally to the strongest decrease of spring NECC (47.63%).

中文翻译：

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全球变暖背景下与ITCZ相关的北赤道逆流的位置和强度变化

以往的研究表明，全球变暖会导致全球海洋环流发生显着变化，但北赤道逆流（NECC）的变化及其机制尚不清楚。在此，我们基于CESM1高分辨率长期模拟，从热带辐合带（ITCZ）的角度研究了全球变暖背景下NECC的位置和强度变化，考虑到NECC和ITCZ之间的密切联系以及完善的研究ITCZ 的变化。结果发现，21世纪末RCP8.5情景下，NECC年均向赤道偏移0.39°，减弱21.71%。 NECC 的变化与季节相关，春季期间变化最大并减弱，与 ITCZ 的变化一致。 ITCZ 的位置和强度变化在 NECC 变化中都很重要，特别是在春季。 ITCZ 的减弱和赤道移动对春季 NECC 最强的下降（47.63%）的贡献几乎相同。