Polar Vortex
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We have examined tropical cyclones and extra tropical cyclones (also known as temperate cyclones) in the earlier posts. Here, we shall examine the polar vortex, also known as the circumpolar vortex.
A polar vortex is a broad area of extremely cold air that sits over the polar region during the winter. This air is usually the coldest air in the Northern Hemisphere.
A polar vortex is a
chilly
Upper troposphere: occasionally reaching the lower stratosphere levels (troposphere reaches up to 8–9 km at poles);
circumpolar
low force
An extensive cyclonic air mass [1000 km] that rotates counter-clockwise in the Northern Hemisphere
Jet streams (Rossby waves) and polar vortex are closely related
It generally forms in the winter and becomes less potent in the summer.
It lies inside the polar front, which is the border dividing the temperate and polar air masses, and envelops polar highs.
Cold Wave and Polar Vortex
When there is a significant temperature differential between the arctic and temperate zones and the Westerlies are present, the polar vortex will stay in its current location.
Weak polar vortex: it disrupts the overall wind flow pattern and invades midlatitude zones. Significant cold outbreaks develop in the midlatitude areas as a result of this.
The United States and Canada, where it happens most frequently, should expect subzero temperatures thanks to the vortex.
How it slides
Over 650 N and S latitudes are traversed by the Polar jet. The jet is extremely powerful and the meandering is minimal when the temperature differential between polar and temperate regions is at its highest.
However, the jet begins to meander (Rossby waves) when the temperature contrast is low, which does not imply that summer has arrived.
Low and high pressure cells alternate as a meandering jet is created. Because of the higher air circulations the jet creates, low pressure cells form below the troughs and high pressure cells below the ridges.
The polar cyclone goes away from the pole and into the temperate zones where there is an intense low pressure when the high pressure cells push over to the north and cause severe meandering.
The high pressure cells weaken as the jet gets stronger and go back to their typical latitudinal positions. The polar cyclone returns to the poles, where it was before the high pressure cells withdrew.
Ozone Hole [South Pole Ozone Depletion]
Ozone depletion and the polar vortex are two different but connected phenomena.
The overall amount of ozone in the stratosphere of Earth is steadily declining at a rate of roughly 4%.
Around Earth's polar regions, there is a far greater drop of stratospheric ozone.
The increase in halocarbons in the atmosphere is the cause of ozone depletion.
A halocarbon is a chemical in which halogens such as chlorine, bromine, iodine, etc. have been added in place of the hydrogen in a hydrocarbon.
The group of reactive non-metallic elements known as halogen includes astatine, fluorine, chlorine, bromine, and iodine.
