Wind Power Input to Ocean Near‐Inertial Waves Diagnosed From a 5‐km Global Coupled Atmosphere‐Ocean General Circulation Model

Abstract

Together with internal tides and lee waves, near-inertial waves (NIWs) are considered as a main source of the canonical 2 TW of mixing energy required to sustain the global overturning circulation (Ferrari & Wunsch, 2009;Munk & Wunsch, 1998;Wunsch & Ferrari, 2004). Investigating the wind power input to surface near-inertial motions is an important step toward quantifying the power available for interior mixing arising from wind-induced NIWs. This investigation has a long history, beginning with estimates based on the mixed layer slab model of Pollard and Millard (1970) that is forced with observed surface wind stress (

Tropical Cyclones Related Wind Power on Oceanic Near‐Inertial Oscillations

“…This suggests that the averaged wind power on NIOs induced by TCs is largely dependent on the occurrence of TCs. Former studies identified a striped enhancement of wind power along specific tracks of TCs (Sun et al., 2021; von Storch & Lüschow, 2023). However, these studies were limited to a 1 year simulation period, which may have resulted in a more localized and fragmented representation of TC‐induced wind power on NIOs.…”

“…However, the Price-Weller-Pinkel model also has limitations due to initial oceanic conditions and model parameterization, which can result in an overestimation of global wind work (see Figure 10 of Plueddemann & Farrar, 2006). These model limitations is neatly illustrated by the substantial variability in the results of near-inertial currents obtained from different model results (von Storch & Lüschow, 2023).…”

“…Numerical models have also demonstrated a prominent local enhancement in the annually averaged wind power on NIOs along the track of TCs, reaching a maximum of 8 mW/m 2 , surpassing the annually averaged wind power induced by winter storms, which reaches a maximum of 5 mW/m 2 (Sun et al., 2021). Furthermore, the surface near‐inertial energy flux induced by TCs has been found to be particularly efficient in promoting interior mixing (von Storch & Lüschow, 2023).…”

“…Consequently, the relative contribution of TCs in terms of wind energy input may be more important, which has gained significant attention (e.g., Sun et al., 2021). The worldwide wind power on NIOs is expected to be underestimated by 10%–33%, when the wind power on NIOs induced by TCs is overlooked (Alford et al., 2016; von Storch & Lüschow, 2023).…”

“…Consequently, models are often employed to calculate the wind power input. However, the choice of different models can significantly impact the results (von Storch & Lüschow, 2023). Liu et al (2008) also proposed several shortcomings of coupled models in simulating currents, including inaccurately initialized oceanic conditions, the absence of air-sea heat flux, and entrainment parameterization.…”