“…The South China Sea (SCS), the largest semienclosed marginal sea in the western tropical Pacific Ocean, records the largest and fastest internal solitary waves (ISWs) in the global ocean (Huang et al., 2016; Klymak et al., 2006; Lien et al., 2014). A variety of in situ and satellite observations (Alford et al., 2010; Chen et al., 2018; 2019; Jackson, 2009; X. Li et al., 2013; Ramp et al., 2010; Wang et al., 2012) and theoretical and numerical models (Lai et al., 2019; Q. Li & Farmer, 2011; A. K. Liu et al., 2004; Xie et al., 2019; Zhao, 2014; 2020; Zhang et al., 2011; Zhao & Alford, 2006; Zheng et al., 2007) have been directed toward understanding and predicting the ISW's characteristics in the northern SCS over the last two decades (Alford et al., 2015; Guo & Chen, 2014). Although the background stratification and current have been found to play important roles in modulating these waves' characteristics and behavior (DeCarlo et al., 2015; Q. Li et al., 2016; Park & Farmer, 2013; Xie et al., 2015, 2016), how the background large‐scale mean motions, especially the typical wind‐driven oceanic circulations (Caruso et al., 2006; Su, 2004), affect them is still not well understood.…”