Over the past few days, unusually cold weather in the eastern United States has brought much attention to a meteorological phenomenon known as the polar vortex. Let us examine the answers to some common questions about polar vortices.
What is a polar vortex?
A polar vortex is a persistent cyclone located near the geographical poles of a planet. In our solar system, they are known to exist on Venus, Earth, Mars, Jupiter, Saturn, and Titan. On Earth, they are located in the upper troposphere and the stratosphere layers of the atmosphere. Their strength is derived from the temperature differential between the warm temperatures at the equator and the cold temperatures at the poles, making them strengthen in winter and weaken in summer. (Saturn has the only polar vortices in the solar system which are formed with polar temperatures higher than equatorial temperatures.) The vortex that normally stays near the North Pole spins in a counter-clockwise direction due to the Coriolis effect.
What happened over the past several days?
While the vortex in question typically stays near the North Pole, it can occasionally split in two and dip into the sub-Arctic, as has happened recently. This led to colder than normal temperatures in the eastern United States as well as in Siberia.
How severe was this event?
Where can this happen again in the future?
This can occur anywhere in the Northern Hemisphere. North America, Europe, and Asia can be affected by dips of the polar vortex. A similar dip was responsible for cold weather in Europe in March 2013.
Are polar vortices related to climate change?
It is not yet clear that there is any relationship between the two. What is clear is that a 2-3 day weather event in one part of the world does not overrule any long-term climate trend for the whole world. However, there are people on both sides of the debate over global warming who do not seem to understand this.