Climate warming has led to the reduction of sea ice in the Arctic Ocean, which has important impacts on ecology, economy and climate. In addition to this long-term variability caused by climate change, weather events affect sea ice on a weekly basis.
In January 2022, the strongest Arctic cyclone observed poleward at 70 degrees north latitude hit northeastern Greenland. A new analysis led by the University of Washington shows that while weather forecasters accurately predicted the storm, ice models severely underestimated its impact on the region’s sea ice.
The study was published in October in Journal of Geophysical Research – Atmosphereshowing that existing models underestimate the impact of large waves on ice packs in the Arctic Ocean.
“The reduction in sea ice over a six-day period is the largest change we’ve seen in historical observations going back to 1979, and the area of ice loss is 30 percent larger than the previous record,” said lead author Ed Blanchard-Wrigglesworth, a research associate. Professor of Atmospheric Sciences at the University of Washington. “Ice models do predict some losses, but only about half of what we see in the real world.”
Accurate sea ice forecasts are an important safety tool for boreal communities, mariners and others operating in Arctic waters. The accuracy of Arctic Ocean forecasts also has wider implications.
“The skill of weather forecasting in the Arctic affects the skill of weather forecasting elsewhere,” Blanchard-Wrigglesworth said.
The January 2022 cyclone has the lowest pressure center estimate above 70 degrees north since satellite records began in 1979. This is an extreme version of a typical winter storm. Climate change does not appear to be the cause of the hurricanes: The researchers found no trend in the intensity of intense cyclones in the Arctic since 1979, and sea ice extent was close to the historical normal for the region before the storm hit.
Record-breaking winds howled over the Arctic Ocean during the storm. The waves grow up to 8 meters (26 feet) high in open water and remain surprisingly strong as they pass through the sea ice. The ice heaves up and down 2 meters (6 ft) near the edge, and NASA’s ICESat-2 satellite shows the waves can travel up to 100 kilometers (60 miles) toward the center of the ice.
Six days after the storm struck, sea ice in affected seas off Norway and northern Russia has thinned significantly, with some areas losing more than half a meter (about 1.5 feet) in thickness.
“It was a huge storm, and the sea ice was hit hard. Sea ice models didn’t predict this loss, which shows that we have ways to improve the model physics,” said second author Melinda Webster, a research assistant professor. University of Alaska Fairbanks. She started the new year in a research position at the UW Applied Physics Laboratory.
The new analysis shows that atmospheric heat generated by the storm had little effect, implying that some other mechanism was responsible for the ice loss. Possibilities, according to Blanchard-Wrigglesworth, include that the sea ice ahead of the storm was thinner than models estimate; , bringing it into contact with sea ice, melting the ice from below.
Unexpected ice loss despite accurate storm forecasts suggests this is an area where models could improve. The researchers hope to monitor future storms to pinpoint exactly what is causing the dramatic decline in sea ice, possibly by placing sensors in the path of upcoming storms in the future.
While the storm doesn’t appear to have anything to do with climate change, as sea ice melts, more open water is allowing bigger waves to erode Arctic coastlines. These waves could also affect remaining sea ice packs, the researchers said.
“Going forward, it’s important to keep this in mind that these extreme events could lead to significant loss of sea ice,” Blanchard-Wrigglesworth said.
Additional co-authors include Linette Boisvert of NASA, Chelsea Parker of NASA and the University of Maryland, and Christopher Horvat of the University of Oakland and Brown University. The research was funded by NASA, the U.S. Navy’s Office of Naval Research and Schmidt Futures.
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