Distribution and Trend of Wind Power Input to Near-Inertial Motions in the Southern Ocean

Abstract

Wind power input to near-inertial motions is an important energy source for generating diapycnal mixing in the ocean. However, the distribution and long-term trend of this input over the Southern Ocean have yet to be quantified. In this study, we investigate the near-inertial wind power input (WPIi) to the Southern Ocean using a global eddy-permitting coupled ocean-sea ice model forced by a high-resolution atmospheric reanalysis product. Our results reveal a zonally asymmetric distribution of WPIi in the Southern Ocean, with the strongest input in the South Indian Ocean and the weakest in the South Pacific. The integrated WPIi between 30°S and 60°S exhibits a significant positive trend over the past four decades due to the intensification of mesoscale weather systems. The surface mixed-layer depth is found to modulate the spatial pattern and trend of WPIi by altering the surface near-inertial currents.