Scientists have found that changes in the polar vortex that are freezing parts of the US. There is Stratospheric patterns to control these cold vacancies.
Although global temperatures are warming, winters in the northern hemisphere continue to be marked by cold vacancies and extreme snowfall episodes.
A study recently in Science Advances It suggests that these extremes of cold are due to an increasingly common pattern in the polar vortex, the low pressure zone that normally circulates over the Arctic.
The disturbances in this area cause them to deform and stretch, throwing cold air in Canada and the US; becoming more common as the Arctic warms up.
“Extreme cold and harsh winter, strong snowstorms and deep snow are associated with these stretching phenomena,” explained one of the study leaders, Judah Cohen of MIT ( Massachusetts Technology Institute), to .
The research team analyzed how these events evolve in the stratosphere, the intermediate layer of the atmosphere that begins about 19 kilometers in altitude.
Normally, the Polar vortex circulates around the north pole like a top. Occasionally, it collapses dramatic, which usually leads the polar air to precipitate to northern Europe and Asia. These collapses can sometimes cause cold vacancies in North America.
Two “special” standards
The new study analyzed data sphere data from satellite observations between 1980 and 2021, as well as winter weather records of the same period. It has been found that, without a total collapse, the polar vortex oscillates and often stretches, like an “artistic skater that extends an arm to balance itself in a complicated rotation”.
There were five different common patterns in the stratosphere. Two of them in particular were linked to the fact that the cold weather reached Canada and the US during these stretching phenomena.
One of the stratospheric patterns tends to bring cold air to the east coastwhile the Another creates a cold in the Midwestern region and the plains.
Since 2015, the Western standard has been more common. It is not known very well why, but this change seems to be associated with, a pattern of unusual cold temperatures in the Equatorial Pacific Ocean.
Over the past two decades, there have been a number of La Niña multianual events.
Is Northern Hemisphere the south of the future?
One big question is how polar vortex ‘aspects can change over time as the globe warms up. Cohen and his team have been analyzing this issue.
“Today, the melting of marine ice is increasing the temperature differences between the west and the east, reinforcing the wave that can disturb the vortex,” Cohen said.
If the marine ice disappeared, the pattern could collapse and reverse. In this scenario, instead of surprisingly cold winters, despite global warming, winter could suddenly become much warmer.
“We could become more like the southern hemispherewhere there is rarely a break from the polar vortex; And that would probably mean warmer average latitudes and a colder Arctic, ”Cohen told Live Science.
