A winter storm has left five people dead in the U.S., school closures, hazardous road conditions, and electricity blackouts. Currently, over 60 million people in 30 states are under weather warnings with seven states under state of emergency. The storm likely caused by a shift in the polar vortex southward may result in severe thunderstorms, tornadoes, and hail in the next coming days.
What is the Polar Vortex?
The polar vortex is made up of a cyclic conduit of strong and fast-moving, upper-air winds that circle the North Pole in a counterclockwise direction, advancing a polar low-pressure system.
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Purpose: These winds serve as a mechanism that prevents the cold arctic air from spreading towards the central part of the earth.
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Disruption: At times the vortex becomes reduced in intensity or even disrupted and this lets cold air into parts of mid-latitude regions such as the United States, Canada, parts of Europe, and Asia.
Types of Polar Vortex
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Tropospheric Polar Vortex:
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Found in the troposphere level up to the altitude of 15 km.
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Said to affect nearly all weather conditions.
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Stratospheric Polar Vortex:
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Accounts to this class are resident in the stratosphere, which ranges between approximately 15 to 50 km in altitude.
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Temporarily disappears during the summer season and is most noticeable in the autumn.
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How does the polar vortex happen?
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Temperature Gradient:
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In winter, the time sunlight shrinks or is nonexistent in the polar regions or cold while in the equatorial region, the temperatures remain high.
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This temperature difference makes a high-speed, narrow current of air form around a polar vortex or the polar night jet.
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Pressure Systems:
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A large temperature contrast provides a stable pattern of a vortex.
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This is problematic because weak pressure differences cause the vortex to become deformed or disrupted.
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Distortion and Arctic Oscillation
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Weaker Jet Streams: To know this, consider what happens when the pressure difference reduces; the jet streams become slower and more wavy, after which they dump Arctic cold air in the low latitudes.
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Arctic Oscillation (AO):
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Positive Phase: Stronger polar vortex, cold air remains confined to the Arctic.
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Negative Phase: Weaker polar vortex, cold air spills southward, leading to extreme weather events like the recent winter storm.
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Climate change Effects and the case of the Polar Vortex
Scientists are actively studying how climate change influences the polar vortex, with key observations including:
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Polar Amplification:
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These are warming at a faster rate than mid and high latitudes, thus declining temperature gradient that fuels the jet streams.
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Weakened Polar Vortex:
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Reduced temperature contrast leads to a weaker and more unstable polar vortex, increasing its likelihood of distortion.
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Role of Arctic Sea Ice:
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As Arctic sea ice diminishes, the dark ocean absorbs more summer heat.
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In winter, this heat is released into the atmosphere, disrupting wind patterns and weakening the polar vortex.
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Effects of the Disturbance of Polar Vortex
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Severe Weather: Severe cold air, large snowstorms, and hazardous roadway and electricity situation in midlatitude area.
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Increased Frequency: Another consequence is, that weak vorticity could cause more disturbances in turning cooler and severe colder winters and extraordinary cold in surprise places.
Conclusion
Application values for the polar vortex itself are important for maintaining global climate balance. However, climate change threatens to disrupt agriculture in the area, for instance through serious winters which are difficult to predict. To counter these effects, global warming has to be tackled, understanding the Arctic and its conditions has to be achieved and infrastructure has to be built capable of enduring severe climate shifts.
