Friday, February 28, 2014

Polar Vortex

  • A polar vortex (also known as an Arctic cyclone, sub-polar cyclone, and a circumpolar whirl) is a persistent, large-scale cyclone located near one or both 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, 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.

Print Friendly and PDF

Blog Archive