Polar Vortex Phenomenon: China’s Mohe city temperature coldest in its recorded history

What’s in today’s article?

• Why in News? 
• What is a Polar Vortex? 
• Is Polar Vortex a new Phenomenon? 
• What is the relation w.r.t. Climate Change?
• News Summary

 

Why in News?  

• Mohe, China’s northernmost city, recorded a temperature of minus 53^oC this week. That was the coldest in its recorded history.
• Scientists say Asia’s extreme cold is largely the result of the Polar Vortex phenomenon.

What is a Polar Vortex? 

Image Caption: Polar Vortex

• The polar vortex is a large area of low pressure and cold air surrounding both of the Earth’s poles. 
• It ALWAYS  exists near the poles, but weakens in summer and strengthens in winter. 
• The term "vortex" refers to the anti-clockwise flow of air that helps keep the colder air near the Poles. 
• Many times, during winter in the northern hemisphere, the polar vortex will expand, sending cold air southward with the jet stream.  
• Jet stream is the area of fast-moving air high in the atmosphere that surrounds the polar vortex.
• This occurs fairly regularly during wintertime and is often associated with large outbreaks of Arctic air in the United States & Canada.
• Portions of Europe and Asia also experience cold surges connected to the polar vortex.

 

Is Polar Vortex a New Phenomenon?

•  Polar vortexes are not something new. 
• The term “polar vortex” has only recently been popularized, bringing attention to a weather feature  that has always been present.
• By itself, the only danger to humans is the magnitude of how cold temperatures will get when the polar vortex expands, sending Arctic air southward into areas that are not typically that cold.

 

What is the relation w.r.t. Climate Change? 

• The polar vortex is held in place by the Earth’s rotation and temperature differences between the Arctic and mid-latitudes. 
• Changes in temperature differences can make the polar vortex expand to more southern latitudes. 
• While this phenomenon occurs naturally, climate change is expected to impact the frequency and severity of polar vortex events.

 

News Summary

• China’s national weather agency issued daily warnings of extremely cold temperatures recently for almost the entire country.
• On the Korean Peninsula, North Korea’s state meteorological agency warned residents in the last week of “the most bitter cold wave in 23 years”. And in South Korea, hundreds of flights were grounded, and beaches were covered in ice.
• Scientists say Asia’s extreme cold is largely the result of the Polar Vortex phenomenon.
• The term refers to an expanse of cold air that generally circles the Arctic but occasionally shifts south from the North Pole.

 

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Q1) What is a Jet Stream?

Jet streams are fast flowing, narrow, meandering air currents in the atmospheres of some planets, including Earth. On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds.

 

Q2) What do you mean by Tropopause?

The tropopause is the upper limit of the troposphere and therefore constitutes the boundary between it and the Stratosphere.

 

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Source: Asia has had a really cold month, courtesy of the polar vortex | Indian Express