A polar vortex (also known as an Arctic cyclone, sub-polar
cyclone, and a circumpolar whirl) is a persistent, large-scale
cyclone
located near either of a planet's geographical
poles.
On Earth,
the polar vortices are located in the middle and upper troposphere
and the stratosphere.
They surround the polar highs and lie in the wake of the polar front.
These cold-core
low-pressure areas strengthen in the winter and
weaken in the summer. They usually span
1,000–2,000 kilometers (620–1,240 miles) in which the air is circulating in a
counter-clockwise fashion (in the northern hemisphere). As with other cyclones,
their rotation is caused by the Coriolis
effect.
The Arctic vortex in the Northern Hemisphere has two
centres, one near Baffin Island and the other over northeast Siberia. In the southern hemisphere, it tends to be
located near the edge of the Ross
ice shelf near 160 west longitude.
When the polar vortex is strong, the Westerlies
increase in strength. When the polar cyclone is weak, the general flow pattern
across mid-latitudes buckles and significant cold outbreaks occur.
Ozone depletion occurs within the polar
vortex, particularly over the Southern Hemisphere, which reaches a maximum in
the spring.
Try and stay warm and safe today...
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