A buoy to measure waves is lowered on to sea ice. Photo / Rob Johnson
Niwa finds waves affect sea ice on larger scale than thought, decreasing ocean barrier
Large waves are apparently to blame for breaking up sea ice on a larger scale than thought, explaining a rapid decrease in Arctic ice.
The finding by Niwa scientists comes from researching how the Southern Ocean's biggest waves were affecting Antarctic sea ice.
Raw video: Monster waves caused Arctic break-up
Their data showed that large waves in the Southern Ocean - those bigger than 3m - were able to break sea ice over greater distances than previously believed.
Read more:
• Ice sheet melt to cause unstoppable sea rise
• Antarctica losing 159 billion tonnes of ice a year
This process may explain the increase in Antarctic sea ice, while Arctic sea ice is decreasing.
The findings were published this week in the scientific journal Nature.
Co-author Alison Kohout said their work had suggested that the role of large waves was more relevant that previously assumed.
"In the Arctic there is a lot of evidence of sea-ice retreat, yet scientists have been unable to reproduce the acceleration of sea-ice retreat in their modelling. This suggests something is missing from the models." Sea ice plays a critical role in moderating the global climate system and the state of the sea ice was an indicator of how climate was changing around the poles, said Dr Kohout. Co-author Mike Williams said new equipment had made the measurements possible.
Ice-breakers
• Big waves are breaking up sea ice more than previously thought.
• New technology allowed researchers to obtain wave data.
• Sea ice plays a key role in moderating global climate.
The hīkoi is expected to arrive at Parliament around midday.