Reflection of the K₁ internal tides (ITs) in the northern South China Sea (SCS) is investigated using a high‐resolution three‐dimensional numerical model. The simulated results indicate that the westward K₁ ITs generated at the Luzon Strait (LS) first impact the continental slope in the northern SCS, and thereafter are reflected. There is a total of 0.31 GW of K₁ energy that are reflected, suggesting a weak reflection considering 3.54 GW of westward K₁ energy from the LS. Two reflected K₁ beams are revealed. The southeast one is the more energetic and can propagate across the deep basin, agreeing with that extracted from satellite altimeter data. The eastward one propagates toward the LS, but it is absent in altimeter results because of its lower intensity. Both the two reflected beams are radiated from the supercritical region in shallow water. Different from the incident waves that are dominated by mode‐1, the reflected waves exhibit a multimodal structure. Contribution of high modes to reflected waves is comparable to that of mode‐1. Moreover, modal content is different for the two reflected beams, with higher proportion of high‐mode energy flux for eastward reflected beam. In contrast to the K₁ ITs, no remarkable reflected O₁ ITs are detected from either simulated or altimeter results. This is due to the weak generation of O₁ ITs at the LS, which leads to less O₁ energy reaching the continental slope. The results of this work can provide essential insight on IT dynamics in the SCS.

Near-inertial waves (NIWs) are a kind of internal wave, which are usually generated by synoptic wind forcing and play an important role in the oceanic energy budget. However, the lack of in situ observations limits our understanding of NIWs to some extent. Through a comparison with in situ observations, in this study, we first showed that the hybrid coordinate ocean model reanalysis results could reasonably reproduce the typhoon-induced NIWs, and we then adopted these data to investigate the NIWs induced by typhoon Megi in 2010 in the South China Sea (SCS). The results indicate that Megi-induced near-inertial kinetic energy was mainly concentrated in the SCS Basin. In the vertical direction, Megi-induced NIWs could propagate to 1000 m depth. The damping and modal content of Megi-induced NIWs were site-dependent: In the region near Megi’s track, NIWs were dominated by the first three baroclinic modes and damped quickly; whereas in two zones to the west of the Luzon Island and Luzon Strait, the e-folding time of Megi-induced NIWs could be longer than 20 days and higher modes (mode-4 to mode-7) were enhanced several days after the passage of Megi. Possible mechanisms of these phenomena were also explored in this study.

Based on the satellite-observed sea surface temperature (SST) data, high-resolution Argo observations and hybrid coordinate model (HYCOM) reanalysis results, this study examined the upper ocean response to Super Typhoon Goni in 2015 in the western north Pacific and revealed the significant diapycnal diffusivity enhancement in the upper ocean induced by Goni. Results indicate that the maximum SST cooling caused by Goni was 7.7 °C, which is greater than the SST cooling caused by most typhoons. The severe SST cooling was related to the enhancement of turbulent mixing induced by Goni. To the right of the typhoon track, the diapycnal diffusivity enhancement in the upper ocean caused by Goni could reach three orders of magnitude, from O (10⁻⁵ m²/s) to O (10⁻² m²/s) and could last at least 9 days after the passage of Goni. In contrast, the diapycnal diffusivity to the left of the typhoon track did not show significant variations. The enhancement of turbulent mixing was found to be consistent with Goni-induced near-inertial kinetic energy calculated from the HYCOM reanalysis results, which suggests that the enhanced turbulent mixing was caused by Goni-induced near-inertial waves.