Quantifying potential contribution of tropical cyclones to oceanic near-inertial internal waves

Abstract Near-inertial internal waves (NIWs) play a crucial role in upper-ocean turbulent mixing through shear instabilities. Tropical cyclones (TCs), with their intense variable winds, contribute significantly to NIWs, yet their global impact has been poorly quantified due to observational and methodological challenges. In this study, we developed a novel data-driven model that integrates hourly satellite-tracked surface drifter data and refined TC records to provide a high-resolution global estimate of TC-induced near-inertial wind power (NIWP), representing a major energy source for the generation of NIWs. Our results show that TCs contribute 0.019–0.024 TW annually to global NIWP, with nearly 45% of this in low-latitude oceans. Moreover, a notable NIW-induced enhancement in thermocline mixing during TC events is identified in subtropical regions, particularly in the northwestern Pacific, based on fine-scale parameterization. Our findings uncover the episodic yet potentially important role of TCs in powering NIWs, with implications for ocean turbulent mixing.