POLAR VORTEX

NEWS: Southward expansion of polar vortex brings extreme cold to United States

ABOUT

• The polar vortex is a large, persistent area of low pressure and extremely cold air that circulates around the Earth’s polar regions.
• Direction of Rotation: It rotates counter-clockwise at the North Pole and clockwise at the South Pole

It exists in two forms:

• Tropospheric polar vortex (lower atmosphere, where weather occurs)
• Stratospheric polar vortex (higher atmosphere, strongest in winter)

FORMATION

• During winter, reduced solar heating at the poles creates intense cold air, generating a strong low-pressure system.
• This system drives fast-moving winds that normally keep Arctic air locked near the poles.

Factors Influencing Polar Vortex Disruptions

• A strong polar vortex keeps the jet stream straight and stable, while a weakened vortex causes it to become wavy, allowing cold Arctic air to move southward.
• Rapid heating of the stratosphere can weaken, displace, or split the polar vortex.
• Faster warming of the Arctic compared to lower latitudes reduces the temperature contrast, increasing instability in the polar vortex.
• Persistent high-pressure blocking systems can redirect cold polar air toward the mid-latitudes.

Impacts of Polar Vortex

• Cold extremes: Rapid Arctic warming (Arctic amplification) is reducing the temperature difference between the poles and mid-latitudes, potentially destabilising the polar vortex and increasing the frequency and intensity of severe winter cold spells.
• Impact on India: The polar vortex does not directly influence Indian weather; however, Arctic air movements can indirectly affect atmospheric circulation by influencing systems such as western disturbances.