As anyone in the Midwest could testify, this past week has been spent in the throes of the freezing cold polar vortex. NASA has documented the phenomena as it moved southward from central Canada into the U.S. from January 20 through the 29th.
A polar vortex is a natural part of nature gone wrong: It starts off as a standard low-pressure system over the Arctic, but when the jet streams keeping these low-pressure systems in check weaken, their freezing cold winds can fall down right onto midwestern American. Beyond extreme discomfort and disruption of services, the freezing cold, which hit 32 below zero in parts of Illinois, is responsible for over 20 deaths.
NASA’s Earth-observing Aqua satellite was able to capture the system’s movement across the globe. Among Aqua’s six instruments is its Atmospheric Infrared Sounder (AIRS), which measures temperature and water vapor as functions of height. Every temperature profile, also known as a sounding, is sensitive to temperature and water vapor. AIRS can measure these soundings using its 2,378 sensors—prior to its launch in 2002, only Earth-observing satellites only had 15 such sensors.
Scientists have found evidence showing weakening Arctic jet streams are more likely due to global warming. While the portrait AIRS paints doesn’t show the jet streams, the temperatures speak for themselves. The coldest temperatures in this image are the purple and blue, which range from -40 degrees Fahrenheit (also -40 degrees Celsius) to -10 degrees Fahrenheit (-23 degrees Celsius). As they hit Illinois and Minnesota, it’s hard not to shiver along with them.
Originally posted on Popular Mechanics