Eddies are rotating bodies of water with diameters between 10-100 km that live from a week to months in the ocean. They are known to carry heat and salt across the Antarctic Circumpolar Current.

Because of extremely limited direct observations of these eddies, it is difficult to calculate the actual amount of heat and salt that these eddies carry.

Here, we present new observations of a cold-core eddy that we sampled during a voyage in the Southern Ocean south of Tasmania. The eddy was born in the Subantarctic Front and travelled into the Subantarctic Zone where it stayed for two months before returning to the Subantarctic Front and disappearing.

The observations showed that the amount of heat carried into the Subantarctic Zone is 2.6 times higher than previously reported, and the amount of salt is 2.5 times larger for south of Tasmania.

Based on our in situ observations, combined with satellite measurements of sea surface height and an eddy-tracking software, the researchers propose that 21% of the heat carried across the Subantarctic Front south of Tasmania is achieved by long-lived, cold-core eddies entering the Subantarctic Zone.

  • Paper: Patel, R.S., H.E. Phillips, P.G. Strutton, A. Lenton, and J. Llort. (2019), Meridional Heat and Salt Transport across the Subantarctic Front by Cold‐Core Eddies, J. Geophys. Res. Oceans, 124. https://doi.org/10.1029/2018JC014655