University of Washington
CREDIT: BEN ADKISON
In the Southern Hemisphere, the ice cover surrounding Antarctica gradually expands from March to October every year. During this time, the total ice area increased 6 times to become larger than Russia. Sea ice then recedes at a faster rate, most significantly around December, when Antarctica experiences continuous daylight.
New research led by the University of Washington explains why the ice is receding so quickly: Unlike other aspects of its behavior, Antarctic sea ice obeys only simple physical rules simple.
The study was published March 28 in Natural geosciences.
“Despite the puzzling long-term trends and the large annual variation in Antarctic sea ice, the seasonal cycle is indeed consistent, consistently showing this rapid retreat relative to growth slowed down. Lettie Roach, who conducted the research as a postdoctoral researcher at UW and is now a research scientist at NASA and Columbia University. “Given how complex our climate system is, I was surprised that the rapid seasonal retreat of Antarctic sea ice could be explained by such a simple mechanism.”
Previous studies have explored whether wind pattern or warm ocean water could be responsible for the asymmetry in Antarctica’s seasonal sea ice cycle. But new research shows that, just as a hot summer day reaches its maximum hot conditions in the late afternoon, the Antarctic summer reaches its peak melting capacity in midsummer, accelerating warming. and sea ice loss, with slower temperature changes and sea ice as solar input. low for the rest of the year.
The researchers investigated global climate models and found they mimic the faster retreat of Antarctic sea ice. They then built a simple physics-based model to show that the cause was a seasonal pattern of incident solar radiation.
In the Arctic, the amount of ice cover in the Arctic has been decreasing since the 1970s along with global warming. However, the Antarctic ice sheet has formed in recent decades. Researchers are still working to understand sea ice around Antarctica and better represent it in climate models.
“I think since we often think of Antarctic sea ice as confusing, previous studies have suggested that the rapid seasonal retreat of Antarctic sea ice is also surprising – in contrast to the Arctic, where the forward and backward ice seasons are more similar,” says Roach. “Our results show that the seasonal cycle in Antarctic sea ice can be explained using very simple physics. As for the seasonal cycle, the Antarctic sea ice is behaving as we should expect, and it is the Arctic seasonal cycle that is even more mysterious.”
Researchers are now looking into why the Arctic sea ice doesn’t follow this pattern, instead growing slightly faster each year than it recedes. Since Antarctica’s geography is so simple, with a polar continent surrounded by oceans, this aspect of its sea ice could be simpler, Roach said.
“We know the Southern Ocean plays an important role in Earth’s climate. Being able to explain this important feature of Antarctic sea ice, which standard textbooks go wrong, and show that models are recreating it correctly, is a step toward understanding this system and predicting it. future changes,” said the co-author. Cecilia Bitza UW professor of atmospheric science.
Other co-authors are; Edward Blanchard-Wrigglesworth, a UW research assistant professor of atmospheric sciences; Ian Eisenman at the Scripps Institution of Oceanography; and Till Wagner at the University of Wisconsin-Madison. Roach is currently a research scientist at NASA’s Goddard Institute for Space Studies. This work was funded by the National Science Foundation, the National Oceanic and Atmospheric Administration, and the UK-based Scientific Commission on Antarctic Research.
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JOURNEYS
Natural Geosciences
DOI
RESEARCH SUBJECTS
Do not apply
ARTICLE TITLE
Asymmetry in the seasonal cycle of Antarctic sea ice due to isolation
ARTICLE PUBLICATION DATE
March 28, 2022
HT / Zoltan
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