“Fifteen years later, AIRS continues to be a valuable asset for forecasters worldwide, sending 7 billion observations streaming into forecasting centers every day.
Besides contributing to better forecasts, AIRS maps greenhouse gases, tracks volcanic emissions and smoke from wildfires, measures noxious compounds like ammonia, and indicates regions that may be heading for a drought.
Have you been wondering how the ozone hole over Antarctica is healing? AIRS observes that too.
These benefits come because AIRS sees many more wavelengths of infrared radiation in the atmosphere, and makes vastly more observations per day, than the observing systems that were previously available. Before AIRS launched, weather balloons provided the most significant weather observations.
Previous infrared satellite instruments observed using about two dozen broad “channels” that averaged many wavelengths together. This reduced their ability to detect important vertical structure. Traditional weather balloons produce only a few thousand soundings (atmospheric vertical profiles) of temperature and water vapor a day, almost entirely over land. AIRS observes 100 times more wavelengths than the earlier instruments and produces close to 3 million soundings a day, covering 85 percent of the globe.
AIRS observes 2,378 wavelengths of heat radiation in the air below the satellite. “Having more wavelengths allows us to get finer vertical structure, and that gives us a much sharper picture of the atmosphere,” explained AIRS Project Scientist Eric Fetzer of NASA’s Jet Propulsion Laboratory in Pasadena, California.
Weather occurs in the troposphere, 7 to 12 miles high (11 to 19 kilometers). Most of the infrared radiation observed by AIRS also originates in the troposphere.”