The 'Polar Vortex:' What is it, and is climate change making it worse?
January 31, 2019
TALLAHASSEE, Fla. (WCTV) — Almost everyone has been talking about it the last few days. But it shouldn’t be a surprise as it has turned much of the Midwest and Great Lakes into Hoth. It’s the polar vortex.
But what is it, really?
Basically, it’s the west to east flow of air aloft hanging around the mid latitudes. It moves around the Earth like a belt. But inside that circle is really cold air. But to make things a little more confusing, there’s not just one polar vortex.
"There's two of them,” said Allison Wing, Ph.D., an assistant professor in the Department of Earth, Ocean and Atmospheric Science at Florida State. “There's one in the troposphere in the lower section of the atmosphere where we observe our weather and it’s strongest right where the jet stream is. And there's another polar vortex in the stratosphere - higher up. But it's the same thing."
The lower vortex (in the troposphere) and the accompanying jet stream has a direct impact on our weather. But the highest vortex in the stratosphere can become unstable, split, and then help to push colder air to the surface.
But the breaks and lobes from the stratospheric polar vortex doesn’t happen very often, according to Wing. It could be a handful, but sometimes only once a season. But sometimes it never happens in a season.
"We have wiggles and wobbles in the jet stream all of the time,” Wing said. “The amplitude in those distortions can be affected by what's happening in the stratospheric polar vortex."
There has also been chatter about the polar vortex and what climate change may - or may not - have to do with it.
The Arctic continues to warm at a much higher rate than the lower latitudes. Because of the uneven warming, researchers have been wondering if that would disrupt the jet stream by slowing the belt of winds.
“[Scientists] then went a step further and had the idea that if the winds slowed down, then that might make things [more wavy], and might make your jet stream have more troughs and ridges, and have higher amplitudes,” Wing said. “And that would cause us to have potentially more extreme cold events, or heat events.”
But science isn’t clear just yet, she said.
"There's a lot of controversy and uncertainty over whether we have actually seen any systematic changes in the jet stream or the polar vortex or its structure,” Wing said.
The research is ongoing, and there is still a lot to learn before we really determine how climate change would impact this infamous circulation.