Down here on the ground, it certainly wasn't hard to see the effects of the polar vortex slipping down over Canada and the U.S. this season. However, seeing it from space just adds a whole new dimension to it.
NASA gathered data from its Aqua satellite, ranging from Dec. 1, 2013 to Jan. 7, 2014, specifically from its temperature-sensing Atmospheric Infrared Sounder (AIRS) instrument, and they put it all together into this short video:
This, and the image at the top of the article (which has temperatures converted to Celsius), have been nicknamed 'The Big Chill' by scientists at NASA's Jet Propulsion Laboratory. They posted these up on their NASA Visualization Explorer website, along with a discussion of exactly what's been happening over the past couple of months:
A persistent pattern of winds spins high above the Arctic in winter. The winds, known as the polar vortex, typically blow in a fairly tight circular formation. But in late December 2013 and early January 2014, the winds loosened and frigid Arctic air spilled farther south than usual, deep into the continental United States. On Jan. 6, 2014, alone, approximately 50 daily record low temperatures were set, from Colorado to Alabama to New York, according to the National Weather Service. In some places temperatures were 40 degrees Fahrenheit colder than average.
[ More Geekquinox: Arctic ice seen disappearing at alarming rate in time-lapse video ]
The term 'polar vortex' may have only shown up recently in the media, but it's not anything new (at least to the Earth or to meteorologists and atmospheric scientists). You can actually find the term in textbooks and journals going back at least 150 years.
Typically, though, forecasters and weather reporters have stuck to talking about the jet stream, since that's something most people are familiar with already. Also, since the jet stream is the southern boundary of where the winds from the polar vortex flow, it's essentially talking about the same thing. However, when the jet stream has dipped so far to the south that it's left us all behind, sometimes it's a bit more useful to talk about where all that frigid air is coming from, rather than what brought it.
(Image courtesy: NASA/JPL/S.Sutherland)
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