Antarctic Eddies: Ice Shelf Melt and Sea Level Rise

Antarctic eddies trigger significant ice shelf melt, impacting glaciers and potentially raising sea levels. Research shows these submesoscale vortices contribute substantially to ice melt, demanding better quantification.

In 2022, a deep-water float gauging salinity, temperature and stress was “recorded” by a huge spinning eddy that ended up being trapped under the Stancomb-Wills ice tongue at another point along the Antarctic shore. With the data later collected from the captured float, Cathrine Hancock at Florida State University and her colleagues approximated that eddies trigger 0.11 metres of thaw under that ice tongue yearly.

Eddies and Ice Tongue Thaw

In the waters around Antarctica, several hundred metres of chillier, fresher water sit on top of warmer, saltier deep water. If a storm comes to be trapped in the tooth cavity under an ice shelf, its swirling presses the cold surface water outwards far from the centre of the vortex, attracting warm deep water up into the resulting void and melting the ice rack from the bottom up.

Poinelli and his colleagues’ modelling revealed that these submesoscale functions was accountable for one-fifth of the total melt of the Thwaites and neighbouring Pine Island freeze nine months. It is the very first research study to evaluate the effect of these tornados throughout a whole ice rack.

Submesoscale Impact on Thwaites Glacier

As much as 10 kilometres wide– making them “submesoscale” features– these storm-like vortices start swirling when waters of various thickness or temperature collide outdoors ocean, just like hurricanes forming via the blend of air bodies in the ambience. And like storms, some of them barrel in the direction of the coast, which in Antarctica is largely comprised of ice racks– the drifting extensions of glaciers that stick loads of kilometres out right into the sea.

The smaller sized submesoscale storms in the Poinelli research study are most likely having a comparable effect, she states– which suggests swirling bodies of water at a variety of scales are melting significant amounts of ice. “Those have to be far better quantified,” states Hancock.

Ice Shelves and Glacier Stability

Ice shelves slow-moving glaciers’ slide into the sea and secure them from wave erosion. If it broke down, the prone Thwaites glacier sheds 50 billion tonnes of ice each year and could increase sea degrees 65 centimetres.