A 22-year (1994–2015) HYbrid Coordinate Ocean Model (HYCOM) global reanalysis is used to study the generation mechanism of the counter-wind characteristic of the South China Sea Warm Current (SCSWC) in winter seasons. Our analysis clearly demonstrates that the counter-wind SCSWC in winter is driven by wind relaxation. An Extended Empirical Orthogonal Function (EEOF) analysis of the hourly Sea Surface Height (SSH) and wind stresses reveals that the most dominant SSH mode is an Ekman mode. When the wind relaxes, the Ekman transport anomaly is offshore and generates a favorable cross-shore SSH slope for the northeastward surface currents over the continental shelf mainly by geostrophic balance. The alongshore pressure gradient force also increases when the wind relaxes, and dominates the weak wind stresses to push the alongshore water northeastwards. We also identify the region south of Taiwan Strait as the origin of the SCSWC, instead of the Hainan Island or Gulf of Tonkin, Vietnam due to the dominant Ekman dynamics.

利用22年（1994-2015）混合坐标海洋模型（HYCOM）全球再分析研究南海暖流（SCSWC）冬季逆风特征的产生机制。我们的分析清楚地表明，冬季逆风 SCSWC 是由风弛豫驱动的。每小时海面高度 (SSH) 和风应力的扩展经验正交函数 (EEOF) 分析表明，最主要的 SSH 模式是 Ekman 模式。当风速减弱时，埃克曼输运异常在近海，主要通过地转平衡为大陆架东北向地表洋流产生有利的跨岸SSH斜坡。当风减弱时，沿岸压力梯度力也增加，并主导弱风应力将沿岸水推向东北。