On the spatial and temporal distribution of near-inertial energy in the Southern Ocean

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Rath, Willi, Greatbatch, Richard John, Zhai, Xiaoming
• Format: Article in Journal/Newspaper
• Language: English
• Published: AGU (American Geophysical Union) 2014
• Subjects: Southern Ocean
• Online Access: https://oceanrep.geomar.de/id/eprint/22854/; https://oceanrep.geomar.de/id/eprint/22854/1/jgrc20537.pdf; https://doi.org/10.1002/2013JC009246

We use an eddying realistic primitive equation model of the Southern Ocean to examine the spatial and temporal distribution of near-inertial wind-power input (WPI) and near-inertial energy (NIE) in the Southern Ocean. We find that the modelled near-inertial WPI is almost proportional to inertial wind-stress variance (IWSV), while the modelled NIE is modulated by the inverse of the mixed-layer depth. We go on to assess recent decadal trends of near-inertial WPI from trends of IWSV based on reanalysis wind-stress. Averaged over the Southern Ocean, annual-mean IWSV is found to have increased by 16 percent over the years 1979 through 2011. Part of the increase of IWSV is found to be related to the positive trend of the Southern Annular Mode over the same period. Finally, we show that there are horizontal local maxima of NIE at depth that are almost exclusively associated with anticyclonic eddies.