Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, and Function Laboratory for Ocean Dynamics and Climate, Pilot National Laboratory for Marine Science and Technology (Qingdao), 7 Nanhai Road, Qingdao, 266071, China.
Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.
Sci Rep. 2020 Jul 16;10(1):11758. doi: 10.1038/s41598-020-68605-y.
The North Equatorial Subsurface Current (NESC) has recently been found to flow westward below the North Equatorial Countercurrent in the subsurface layer across the Pacific Ocean. The structure, water mass properties, and the dynamics of the NESC are studied using Argo profiles and geostrophic currents, combined with moored current meter observations. The mean westward geostrophic currents of the NESC has been validated with moored current meter measurements at 4.7° N, 142° E in the far western tropical Pacific Ocean. Sizable seasonal-to-interannual variability of the NESC is indicated by the observations, with strong transports in boreal summer and during La Niña events, whereas weak transports in boreal winter and during El Niño events. The water masses of the NESC appear to be the mixture of the North and South Pacific intermediate waters, with the waters immediately below the thermocline closer to the North than to the South Pacific waters. A simulation using a linear continuously stratified model of ocean circulation suggests that the mean NESC is forced by wind curl through low baroclinic mode responses of the ocean.
北赤道次表层流（NESC）最近在北赤道逆流下方的次表层中被发现向西流动，横跨太平洋。利用 Argo 剖面和地转流，结合系泊海流计观测，研究了 NESC 的结构、水团特性和动力学。NESC 的平均向西地转流已经过位于远西热带太平洋的 4.7°N，142°E 的系泊海流计测量得到验证。观测结果表明，NESC 存在明显的季节性到年际变化，在北半球夏季和拉尼娜事件期间，输送较强，而在北半球冬季和厄尔尼诺事件期间，输送较弱。NESC 的水团似乎是北太平洋和南太平洋中层水的混合物，其紧邻温跃层下方的水团比南太平洋水团更接近北太平洋。利用海洋环流的线性连续分层模式的模拟表明，平均 NESC 是由风的卷曲通过海洋的低斜压模态响应而产生的。
