What Is the Polar Vortex?
What happens during a polar outbreak event? In this informative video by Earth Vision Trust, Mark Serreze of the National Snow and Ice Data Center explains how fluctuations in the polar front jet stream brought record low temperatures to the U.S. in January 2014.
Earth Vision Trust is a non-profit founded by National Geographic photographer and grantee James Balog that seeks to educate and inspire the public through innovative visual exploration of the changing environment.
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Mark Serezze
Director, National
Snow and Ice Data Center
What happened during this polar vortex event? Some parts saw
very cold, and things like snowy conditions, such like in Chicago.
What we saw was what we call a polar outbreak.
What is the polar vortex? The polar vortex is always there,
this immense whirlpool of cold air that’s centered basically over the
Arctic. It’s a vortex that has many
eddies within it as well. And some times these eddies get big and they extend
down to the south.
The boundary of the polar vortex is really the boundary
between the cold polar air to the north, and the warmer sub-tropical air. And
that boundary is actually defined by something we call the polar front jet
stream. A narrow band of very, very fast moving air, generally moving from west
to east. But that boundary shifts all
the time. Sometimes it moves north, sometimes south, now it shrinks in summer,
pole-ward, and winter it starts to dip down to the south. So of course that’s
in winter when we have those big polar outbreaks because we’re more likely to
see that polar vortex effect us.
What we had this January was we had these dips
occurring right over the Mid-west. If
you have a big outbreak of cold air, that’s affecting things like
transportation. At the same time, affecting things like agricultural practices
and air travel. These are, sort of, questions out there that are real-world
that we have to be thinking about.
This really can affect you. This is a very, very active area
of research how this can be linked to the process of global warming, and this
was a particularly severe one. Even though it was very, very cold, say around
Chicago, in other parts of the planet it was unusually warm. These changes are
occurring day-to-day, week-to-week, month-to-month.
What you see for the temperature record for Chicago is that
overall there’s a rise, these sort of outbreaks that we see and they’ve occurred
in the past, they will occur in the future. And that’s just the nature of how
this polar vortex works. The questions
out there is the frequency of these
outbreaks going to change.
The weather machine is going to respond to that, just how,
we don’t quite know yet.
