Polar Vortex: Meaning, Features, Working, Duration & Strength

The term "Polar Vortex" has become one of those hot topics, particularly with the relevance to extreme weather events. A polar vortex is the big area of low pressure and cold air encircling both of Earth's poles. It is always near the poles but weakens during summer and strengthens during winter. In this context, the term "vortex" refers to the counterclockwise motion of air that aids in keeping the cold air near the poles. Many people do not know this until it hits them when their weather becomes greatly affected and unusual cold snaps hit other parts of the country.

In the context of the UPSC Civil Services Examination, the topic of Polar Vortex is significant in General Studies Paper I under the subject of Geography. Understanding the intricacies of natural phenomena such as the Polar Vortex is important for the aspirants. It serves as a foundation for various related topics and constitutes an important part of the UPSC syllabus.

Polar Vortex Meaning

The Polar Vortex is a nearly permanent, large-scale cyclone near the Earth's geographical poles. This high-altitude low-pressure system circulates in the stratosphere and encompasses both the North and South Poles. During the winter months when there is a steep temperature gradient between the polar and mid-latitude regions, the stratospheric polar vortex becomes strong, significantly influencing weather patterns by containing polar air. It acts in effect as a very large-scale meteorological feature which would tend to trap frigid air within the polar regions rather than spilling into lower latitudes.

Duration and Strength of a Polar Vortex

Strength and duration of polar vortices change from month to month due mainly to the seasonal cycles. During winter, the polar vortex is stronger because the temperature contrast between the equator and the poles is larger. This usually happens in the Northern Hemisphere from November to April, peaking during mid-winter but weakening as spring approaches. Other climatic patterns also affect the duration and strength of the polar vortex: El Niño and La Niña events. These events modify the global weather patterns and thereby affect the behavior of the polar vortex. When the vortex is strong, it confines the cold air mass very well within the Arctic, while when it weakens, the cold air breaks out and moves towards lower latitudes.

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Key Features of Polar Vortex

Some of the major features of the polar vortex include the following:

• Location: The polar vortex is mainly located in the stratosphere in the polar regions but tends to have a stronger impact in the Northern Hemisphere, where it interacts with the North American, European, and Asian climates.
• Wind Patterns: The vortex consists of strong west-to-east winds circulating over the poles. These are a barrier containing cold air in the polar region. The strength and stability of these winds are vital for maintaining the containment of cold air.
• Temperature Variation: In the vortex, temperatures can sometimes drop to very low levels to as low as -80°C (-112°F) at times in the stratosphere. This cold air is generally locked inside unless it gets disturbed.
• Seasonal Change: The strength of the vortex varies largely with the seasons. Polar vortices are considerably stronger in winter due to the large temperature difference between the equator and the pole and weak in summer months.

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Working of a Polar Vortex

The polar vortex functions on intricate atmospheric dynamics. In the winter, the temperature gradient between the Arctic and the equator increases, and therefore, the wind speed intensifies, circulating counterclockwise around the pole. This circumpolar flow acts as a kind of barrier, keeping the cold polar air in place. However, some disturbances, such as SSW events, can disrupt this flow. These events cause rapid warming of the stratosphere, weakening the vortex and often causing parts of the cold Arctic air to move southward. This leads to severe winter weather in the mid-latitudes because the cold air masses are no longer contained and can reach regions usually unaffected by such frigid temperatures.

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Polar Vortex and Global Warming

Global warming has profound and complex interactions with the polar vortex. On the surface, a warming planet might suggest milder winters. However, in reality it isn't. Thawing Arctic sea ice and warming temperatures in the Arctic weaken the jet stream—a fast-moving ribbon of air that determines much of our weather—and send it meandering off more frequently and for longer periods. These anomalies, for instance, can break or weaken the polar vortex thereby leading to parts of the vortex breaking off and moving downwards. This then leads frigid Arctic air into more latitudes. This fact helps explain why, ostensibly paradoxically, global warming can lead to an upsurge in extreme cold events and frequent cold event occurrences in some areas although the overall global temperature might rise.

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Polar Vortex Reversal

Polar vortex reversal is a weakening or breakdown of the polar vortex, typically caused by sudden stratospheric warming (SSW) events. In SSW events, temperatures in the stratosphere may rise by as much as 50°C (about 90°F) in a few days, weakening the polar vortex significantly. The disruption may cause the vortex to split or displace, and the cold Arctic air masses may move equatorward. The extreme effect of the vortex reversal may result in longer durations of severe cold over areas otherwise accustomed to much more tolerable winters, thereby determining the winter weather and further altering the rest of the following weather patterns.

Impacts of the Polar Vortex Reversal

Reversal or weakening of the polar vortex may result in great and widespread effects on weather conditions globally:

• Extreme Cold Events: The time when the polar vortex breaks down leads to polar air escaping into lower latitudes. It brings about extreme severe cold spells in North America, Europe, and Asia at unexpected times.
• Snowfall: Areas that rarely record heavy snowfall might expect increased snow events. Snowfall in the United States is a case in point. It has occurred there during the polar vortex instances in 2014 and 2019.
• Agriculture: Prolonged extreme cold can reduce agricultural productivity, destroy crops and disrupt food chains. This can significantly devastate the winter crops while delaying early spring planting.
• Infrastructure: Extreme cold conditions can drive up heating demands, burdening energy infrastructure, or heavy snow may disrupt all transportation systems impacting commuting, shipping, and flying.
• Health: Exposure to intense cold for an extended period can increase the risks of health problems, including hypothermia and frostbite. Heart disease, for instance, may worsen with the condition. Elderly people and homeless populations are also at risk.

We hope your doubts regarding the topic have been addressed after going through the above article. Testbook offers good quality preparation material for different competitive examinations. Succeed in your UPSC IAS exam preparations by downloading the Testbook App here!