Rossby

But the Arctic is warming on average far more quickly than most other parts of the Earth, and this appears to be destabilizing the jet stream, causing it to develop so-called Rossby waves, which suck hot air from the south and park it in temperate regions that normally do not see extreme heat for days or weeks at a time.

The study identified a disruption in the jet stream similar to the Rossby waves thought to affect Europe and Russia.

"Our work uncovered patterns in climate events driven mainly by atmospheric Rossby waves, which are large inertial planetary waves that naturally occur in rotating fluids and cause movement within the atmosphere," said Fan.

These are called Rossby waves.

In a 2019 study Kornhuber and colleagues showed that a repeating Rossby wave pattern known as a wave-7 -- that is, seven giant peaks and seven matching troughs spanning the globe -- draws warm, dry air from the subtropics up to the midlatitudes, causing concurrent summer heat waves and droughts in predictable parts of North America, Europe and Asia.