Observation of Typhoon Trami (2024)-induced energy cascade from near-inertial waves to diurnal internal tides

Energy transfers among internal waves in the northern South China Sea are not well characterized, particularly during typhoons, owing to the lack of in situ observations. Based on high-resolution mooring data collected during Typhoon Trami (2024), this study reveals the occurrence of robust vertical energy redistribution among diurnal internal tides (D1 ITs) and near-inertial waves (NIWs). Strikingly, the typhoon not only amplified the NIW energy but also triggered an unexpected surge in the D1 IT energy. The observed average net energy transfer rate of 1 × 10 −7 W kg −1 from typhoon-forced NIWs to D1 ITs occurred at water depths of 120–170 m. Further bispectral analysis indicated that the energy transfer is driven by nonlinear wave–wave interaction. These results reveal the existence of a new energy transfer pathway—from atmospheric forcing to D1 Its—and redefine the redistribution of the internal wave energy during extreme weather events. 摘要: 台风期间内波间的能量传递特征及机制尚未得到清晰揭示.本研究利用 2024 年南海北部“潭美”台风期间获取的高分辨率潜标观测数据, 发现全日内潮与近惯性内波之间存在显著的垂直能量串级现象.台风作用下, 观测发现在近惯性波能量显著增强的同时, 全日内潮能量亦出现激增;在 120-170 米深度范围的水层, 观测到台风强迫下近惯性波向全日内潮的平均净能量传递率达 1×10⁻⁷ W/kg.双谱分析结果进一步证实, 这一能量传递过程由非线性波-波相互作用主导驱动.上述结果揭示了“大气强迫至全日内潮”这一全新的内波能量传递路径, 进而重新界定了极端天气事件作用下内波能量的再分配规律.