Research brief: Southern Ocean vortices are changing

Picture above: Inside a wave by Joshua Dewey (Unsplash).

It is well accepted that climate change results in the intensification of the winds, in particular of those blowing over the Southern Ocean. Despite previous research showing an increase of the high-frequency motions in the Southern Ocean due to the intensification of the winds, we still do not know how swirling vortices of tens to hundreds of kilometres in the ocean have responded to climate change.

In this study, researchers used satellite observations of the sea surface height from 1993 to 2017 to look for changes in the swirling vortices. The focus of the study was on the Southern Ocean as it is one of the areas with more vortices and plays a key role in controlling the climate.

The researchers found that the energy of the vortices has increased over the past two decades. Using this method, they were able to pinpoint that the energy increase occurs due to an increase in the mean amplitude of the vortices rather than an increase in their number. Finally, the vortices showed a clear response to the strengthening of winds in the Southern Ocean.

  • Paper: Martínez‐Moreno, J., Hogg, A. M., Kiss, A. E., Constantinou, N. C., & Morrison, A. K. ( 2019). Kinetic energy of eddy‐like features from sea surface altimetry. Journal of Advances in Modeling Earth Systems, 11.

By Alvin Stone

Alvin worked as an editor with Fairfax Community News and then News Local for over a decade before moving across to media communications. As a media communicator he has worked for WWF-Australia and most recently Primary Communication, a boutique agency specialising in corporate clients in the energy, transport, IT and not-for-profit sectors.