Recently, the arctic region has been rapidly warming. This has been linked to extreme cold weather in the US. These are a result of the expansion of the Polar Vortex.

What is Polar Vortex?

• It is a mass of cold, low-pressure air that consistently hovers over the Arctic region.
  
• It is denoted by the word “vortex” because it spins counter-clockwise, just like a hurricane does.

What are the Reasons for expansion of Polar Vortex?

• Usually, the polar vortex remains strong and compact like the mass of frigid air that stays at the North Pole.
• But sometimes it weakens and expands to influence the jet stream.
• Once the jet stream is impacted, the cold polar air finds its way toward the midlatitude regions.
• Researchers found that the expansion of the polar vortex has been occurring more frequently due to the rapidly warming Arctic.

Duration and Strength of a  Polar Vortex

The duration and strength of a Polar Vortex are as follows:

Strength

• A Polar low-pressure area is at its highest during the winter and its lowest during the summer.
• In the event of a volcanic eruption, a polar vortex will be further strengthened and it can stay that way for up to two years after the initial eruption
• There will be a single vortex when the Arctic low-pressure is elongated in shape with two cyclone centres.
• The Antarctic polar low-pressure is far more persistent than the Arctic variant.
• Climate phenomena related to the La Nina will significantly strengthen a polar low-pressure.

Duration

• The Arctic polar vortex breaks up between mid-March to mid-May. This event marks the end of winter and the beginning of spring. Farming activities, ecosystems, and other weather cycles are impacted by this event
• An early breakup of the polar low-pressure leads to one warming period that lasts from late February to mid-March. A late breakup period will lead to two warming periods, one in January and one in March.

Polar Vortex and Global Warming

Many a time, the polar low pressure is associated with global warming. It is believed that many global warming issues are caused due to polar Vortex.

• The worldwide temperature has increased by approx. 0.8°C since the 1880s.
• The Arctic has heated and melted at more than double the rate due to the polar low pressure.
• The North Pole, North America, and other similar regions have very little temperature difference from the Arctic region.
• The jet stream’s energy moves upward, disturbing the Polar Vortex and initiating it to split.

Impacts of Polar low-pressure area on Earth’s atmosphere

1. Abrupt stratospheric warming due to the polar Vortex can lead to the warm Arctic region in the stratosphere as well as the troposphere.
2. It favours cold air and causes more harsh winter weather in the Northern Hemisphere and mid-latitudes comprising the Eastern United States.

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