Storm waves a factor in sea ice retreat

Large waves generated by ocean storms have a greater impact on the breakup and retreat of sea ice than previously thought.

The Aurora Australis sailing through the marginal ice zone. Credit: Alison Kohout

New research from NIWA, published this week in Nature, suggests that large ocean waves whipped up by storms can fracture Antarctic sea ice hundreds of kilometres from the ice edge and accelerate sea-ice retreat.

Using data collected from sensors placed a varying locations on the off the coast of Antarctica the researchers were able draw the clearest picture to date of how waves travel through the ice.  Their new data shows that large waves in the Southern Ocean – those bigger than 3 m – are able to break sea ice over greater distances than previously believed, and that this process may be the missing science that explains the increase in Antarctic, and rapid decrease in Arctic, sea ice extent.

NIWA Researcher Dr Alison Kohout highlighted the importance of factoring the new findings into current models of sea ice retreat.

“Our work has suggested that the role of large waves is more relevant that previously assumed,” she said.

“In the Arctic there is a lot of evidence of sea ice retreat, yet scientists have been unable to reproduce the speed of sea ice retreat in their modelling. This suggests something is missing from the models.”

The research has been widely covered both in New Zealand and internationally, examples include:

The Press: Freak waves prove to be ultimate icebreaker
3 News: Wave size clue to Antarctic ice puzzle
New Zealand Herald: Monster waves to blame for Arctic ice break-up
Radio New Zealand: Big waves play part in breaking sea ice
Science AAAS News: Shrinking Waves May Save Antarctic Sea Ice
BBC News: BBC News – Ocean waves influence polar ice extent
Business Insider Australia: Big Storm Waves Are Cracking The Antarctic Sea Ice Wall And Accelerating Its Retreat
Climate Central: Big Waves Bust Up Sea Ice, May Be Playing Role in Melt