Previous studies proposed that the increase in the eddy kinetic energy (EKE) in the Southern Ocean in recent decades is primarily caused by the strengthening of circumpolar surface westerlies. However, the spatial pattern of EKE change does not match the pattern of wind change. Here, we revisit the relationship between EKE and wind stress through an observational analysis and model experiments and show that the change in EKE is primarily determined by the mean flow. The increasing wind stress intensifies the circumpolar mean flow contributing to increasing EKE; yet strong EKE variations are generally confined downstream of major topographic features. This arises from the releasing of available potential energy as the mean flow passes through the topography. Our results indicate that the change in Southern Ocean eddy activity has a distinct localization characteristic due to the strong dynamical influence of topography.

Previous studies have demonstrated that surface wave breaking can impact upper‐ocean turbulence through wave‐breaking‐induced turbulence kinetic energy (TKE) flux and momentum flux. Wave‐breaking‐induced momentum flux decays approximately exponentially with depth, and the decay exponent depends on both the wind speed and wave age. With increasing wave age, the decay speed of wave‐breaking‐induced momentum flux first decreases, reaching a minimum around a wave age of 16, and then increases. In this study, a wave‐breaking‐induced momentum flux parameterization was proposed based on wave age and wind‐speed dependence. The new proposed parameterization was introduced into a one‐dimensional (1‐D) ocean model along with a wave‐age‐dependent wave‐breaking‐induced TKE flux parameterization. The simulation results showed that the wave‐breaking impact on the ocean mainly affected the upper‐ocean layer. Adding the wave‐age impact to the wave‐breaking‐induced TKE flux and momentum flux improved the 1‐D model performance concerning the sea temperature. Moreover, the wave‐breaking‐induced momentum flux had a larger impact on the simulation results than the wave‐breaking‐induced TKE flux.