About 16 pct of Antarctic sea-ice affected by ocean waves: study

MELBOURNE, May 29 (Xinhua) -- About 16 percent of Antarctic sea ice is affected by waves from the rough Southern Ocean, Australian-led research reveals, offering the first clear picture of a crucial but understudied region called the Marginal Ice Zone (MIZ).

Published in Nature Communications, the University of Tasmania (UTAS)-led study used old satellite radar techniques applied to a 2013 French-Indian satellite to measure wave heights entering sea ice over 12 years (2013-2024), according to a statement from the Australian Antarctic Program Partnership (AAPP) released Thursday.

Unlike previous methods that defined the MIZ by arbitrary ice-concentration thresholds, this approach measures the actual World Meteorological Organization definition: ice affected by waves and swell from the open ocean, said study lead author Alex Fraser from the AAPP at UTAS.

The wave-affected MIZ forms a 35-180 km-wide ring around Antarctica's sea ice, widest in winter and early spring when the ice edge meets high-wave regions of the Southern Ocean, the study showed.

"When sea ice isn't affected by waves, it forms a more complete 'cap' on the ocean, limiting the exchange of heat, moisture and gases (e.g., carbon dioxide) with the atmosphere. When waves jostle the ice and break it up, gaps between ice floes allow these exchanges to increase," Fraser said.

"The MIZ is also important for shielding inner-pack ice, fast ice, and ice shelves from waves, and for sustaining marine life when meltwater at the retreating ice edge supports strong phytoplankton blooms that feed krill and in turn, penguins, seals and whales," he added.

Understanding wave-ice interactions is key to explaining Antarctic sea ice's dramatic decline since 2016, researchers said, adding the findings will guide Australia's 2028 icebreaker voyage to East Antarctica's MIZ. ■