The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft captured this infrared image of the first of a series of storms approaching the Pacific Northwest at 2141 UTC (1:41 p.m. PST) on Nov. 28, 2012, marking the beginning of an "atmospheric river" event. Atmospheric rivers are narrow regions in Earth's atmosphere that channel and transport enormous amounts of water vapor across the Pacific or other regions. Areas of deep blue and violet mark the highest and coldest cloud tops, the result of strong convection and the location of precipitation. The flow of moisture (nicknamed the "Pineapple Express") visible south of the low pressure system is expected to intensify the rainfall, causing very heavy rains and possible flooding as well as debris flows in the mountainous burn areas of Northern California.
The Atmospheric Infrared Sounder, AIRS, in conjunction with the Advanced Microwave Sounding Unit, AMSU, senses emitted infrared and microwave radiation from Earth to provide a three-dimensional look at Earth's weather and climate. Working in tandem, the two instruments make simultaneous observations all the way down to Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, three-dimensional map of atmospheric temperature and humidity, cloud amounts and heights, greenhouse gas concentrations, and many other atmospheric phenomena. Launched into Earth orbit in 2002, the AIRS and AMSU instruments fly onboard NASA's Aqua spacecraft and are managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.
More information about AIRS can be found at http://airs.jpl.nasa.gov.