Strongest Arctic cyclone on record led to startling loss of sea ice, study shows

Global warming is causing a decrease in sea ice in the Arctic Ocean, where the loss of sea ice has significant ecological, economic and climatic impacts. In addition to this long-term change due to climate change, weather events affect the sea ice from week to week.

The most powerful arctic cyclone ever observed towards the pole of 70 degrees north latitude struck in January 2022 in northeast Greenland. New analysis by the University of Washington shows that while weather forecasts accurately predicted the storm, ice models seriously underestimated its impact on the region’s sea ice.

The study, published in October in the Journal of Geophysical Research: Atmospheressuggests that existing models underestimate the impact of large waves on sea ice in the Arctic Ocean.

“The six-day loss of sea ice was the largest change we could find in historical observations since 1979, and the area of ​​ice lost was 30% greater than the previous record,” the lead author said. Ed Blanchard-Wrigglesworth, a research assistant. professor of atmospheric science at UW. “The ice models predicted some loss, but only about half of what we’ve seen in the real world.”

Accurate sea ice forecasts are important safety tools for northern communities, mariners and others operating in Arctic waters. Forecast accuracy in the Arctic Ocean also has wider effects.

“The skill of a weather forecast in the Arctic affects the skill of weather forecasts in other places,” Blanchard-Wrigglesworth said.

The January 2022 cyclone had the lowest estimated center of pressure since satellite records began in 1979 above 70 degrees north. It was an extreme version of a typical winter storm. Climate change does not appear to be responsible for the cyclone: ​​researchers have not found a trend in the strength of intense Arctic cyclones since 1979, and the sea ice surface was close to the historical normal for this region before the storm hits.

During the storm, record winds blew over the Arctic Ocean. The waves reached 8 meters (26 feet) high in open water and remained surprisingly strong as they cut through the sea ice. The ice heaved 2 meters (6 feet) up and down near the edge of the pack ice, and NASA’s ICESat-2 satellite shows that the waves reached up to 100 kilometers (60 miles) towards the center of the pack ice.

Six days after the onset of the storm, sea ice had thinned significantly in affected waters north of Norway and Russia, losing more than half a meter (about 1.5 feet) in places. ‘thickness.

“It was a monstrous storm and the sea ice was beaten up. And the sea ice models did not predict this loss, suggesting that there are ways to improve the physics of the model,” said said second author Melinda Webster, assistant research professor at the University of Alaska Fairbanks. She’s starting a research position in the new year at UW’s Applied Physics Lab.

The new analysis shows that atmospheric heat from the storm had a small effect, meaning another mechanism was to blame for the ice loss. Possibilities, suggests Blanchard-Wrigglesworth, include sea ice that was thinner before the storm hit than models had estimated; that the storm waves broke through the pack ice with more force than the models predicted as they penetrated deep into the pack ice; or that the waves churned up deeper, warmer water and brought it into contact with the sea ice, melting the ice from below.

The unexpected ice loss, despite an accurate storm forecast, suggests this is an area where models could improve. Researchers hope to monitor future storms to identify exactly what led to the dramatic loss of sea ice, potentially by placing sensors in the path of an approaching future storm.

Although this storm does not appear to be linked to climate change, an increasing amount of open water as sea ice melts allows for larger waves that erode Arctic coastlines. These waves, the researchers say, could also affect the remaining pack ice.

“Looking forward, keep in mind that these extreme events could produce these episodes of huge sea ice loss,” Blanchard-Wrigglesworth said.

Other co-authors are Linette Boisvert from NASA, Chelsea Parker from NASA and the University of Maryland, and Christopher Horvat from the University of Auckland and Brown University.