What is the 'sudden stratospheric temperature rise' that brings a record-breaking cold wave to the continent?

United Kingdom Meteorological Agency is a British national weather station, is the atmospheric layer from the surface to 10km ~ 50km stratospheric rise temperature of a sudden ' stratospheric sudden warming was observed phenomenon' to early January 2021. It has been pointed out that this phenomenon could bring record-breaking cold waves to Europe and Siberia.

New year begins with a sudden stratospheric warming | Official blog of the Met Office news team

Beast from the East 2? What'sudden stratospheric warming' involves and why it can cause freezing surface weather

In winter, the Arctic Circle is 24 hours a night, so the stratosphere above the Arctic Circle drops below -60 ° C. As a result, a strong westerly wind blows over the Arctic Circle, forming a strong wind vortex called a polar vortex . However, in rare cases, when the polar vortex weakens, a 'sudden stratospheric temperature rise' occurs in which the average temperature of the stratosphere over the Arctic Circle suddenly rises by up to 50 ° C in a few days.

When the stratosphere suddenly rises, the cold air in the sky drops, and the jet stream that meanders eastward around the earth is strongly affected. When the jet stream crosses the Atlantic Ocean, it usually points toward the United Kingdom, but the rapid temperature rise in the stratosphere causes the jet stream to move toward the equator and weaken.

Then, the warm air that originally blows to Europe will be replaced by the cold air from Siberia and the Arctic, and there is a possibility that Europe and North Asia will be hit by a large cold wave for a long time. In fact, the great cold wave called ' Beast from the East ' that struck Europe in February 2018 is said to have been caused by the sudden rise in the stratosphere.

Video: 'Beast from the East' hit directly in London, England 1 photo International News: AFPBB News

There is a theory that this sudden stratospheric temperature rise is likely to occur when the ' La Nina phenomenon ' occurs in the Pacific equatorial region where the sea surface temperature continues to be lower than normal.

It has been confirmed that the La Nina phenomenon has actually continued since the end of 2020, and it is said that the temperature of the stratosphere suddenly changed from around December 2020. Climatologist Simon Lee reports that a sudden rise in the stratosphere has been confirmed since around January 2021.

The Met Office has confirmed the weakening of the polar vortex in the stratosphere and predicts that a sudden temperature rise in the stratosphere will have a 70% chance of severe cold throughout the UK. Paul Davis, a senior researcher at the Met Office, said, 'A sudden rise in the stratosphere is inevitable for cold waves. However, weather data in the United Kingdom becomes unstable but relatively calm in a week or two. It confirms that we will be back. '

In addition, although the La Nina phenomenon occurred at the end of 2019, NASA has announced that 2020 was still 'the hottest year in the history of observation records'. In the unusual situation of 'the temperature rises despite the fall in sea surface temperature,' climate scientist Sieg Housefather said, 'The La Nina phenomenon will definitely have a cooling effect at the end of 2020. Nevertheless, 2020 The fact that the year was the hottest suggests that global warming has progressed over the last five years, 'he said, urgently reducing carbon emissions.

in Science, Posted by log1i_yk