Imagery from the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite showed the movement of cold, Arctic air over the United States from Dec. 1-11, 2016. The frigid air mass affected states from the north central to northeastern and Mid-Atlantic areas.
The AIRS instrument measures temperature data in infrared light. At NASA's Jet Propulsion Laboratory in Pasadena, Calif., scientists collected a series of AIRS images depicting the temperature of air at approximately 18,000 feet. Temperatures at that level of the atmosphere were minus 30 degrees Celsius (minus 2 degrees Fahrenheit) or less.
AIRS imagery shows cooler temperatures in darker blue and warmer temperatures in dark orange. The edge of the blue indicates the border of the cold air.