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The Barents Sea, north of Norway and east of the Svalbard archipelago east of Greenland is being Atlanticised and remains largely ice free even in the Arctic winter.New research shows that Arctic climate changes during the next few weeks may determine if and when the Eastern United States gets another extreme cold wave this coming winter.
Since the 1980s, Arctic sea ice extent has been dropping sharply, while the extent of land covered by snow in Siberia during autumn has increased. Those changes have combined to more frequently contort the “polar vortex” of high-altitude Arctic winds into a dumbbell shape that increases the potential for severe winter weather outbreaks like February’s Texas freeze, the study, published in Science Thursday, shows.
Arctic sea ice this year is once again near a record low, and medium range forecasts call for relatively cold and snowy conditions in Siberia, potentially setting the stage for renewed winter extremes at lower latitudes.
Disruptions of the polar vortex—a belt of strong, high altitude winds usually circling the central Arctic—have become more frequent in the last 40 years, the new research found. In the study, the researchers write that the lack of sea ice in the Barents-Kara Seas and heavier snowfall over Siberia combine to build a wave of high pressure in the atmosphere between Northern Europe and the Ural Mountains, along with low pressure over East Asia.
During the Texas freeze parts of the Arctic were 28°C warmer than normal! The Arctic is changing and driving climate extremes in the high and medium northern latitudes.If their rising energy is absorbed by the upper atmosphere, it’s more probable that the circulation above the Arctic will remain stable. But sometimes if that energy bounces downward off the polar vortex it distorts the vortex, pushing one end of the cold dumbbell over Siberia and the other toward the eastern half of the United States.
Why that energy is sometimes reflected downward remains one of the big climate mysteries, said study author Judah Cohen, a Boston-based climate researcher and director of seasonal forecasting with Atmospheric and Environmental Research (AER). But how the process can drive winter extremes was shown in February 2021, when bitter Arctic air swept southward across Texas and even into Mexico.
The freezing conditions across Texas killed 210 people and crippled regional transportation and power grids. The National Oceanic and Atmospheric Administration reported that the region’s prolonged exposure to Arctic air resulted in power outages affecting nearly 10 million people across the South. NOAA estimated the cost at more than $20 billion, making it the costliest winter extreme event on record in the United States. and the nation’s costliest climate-related extreme of the year so far.
Worth reading the whole article.
Original paper: https://www.science.org/doi/10.1126/science.abi9167 —the WHOLE article is available online.