AIRS, the Atmospheric Infrared Sounder, is the primary Aqua sensor for measuring the earth’s water cycle. BAE Systems developed AIRS for NASA’s Jet Propulsion Laboratory.
Today, flying in a polar orbit at an altitude of 705 kilometers, NASA’s Aqua spacecraft is collecting data on earth systems and weather features in a scope and detail not seen before. Aqua, launched on May 4, 2002, as part of the Earth Observing System, collects data related to global water cycles with the goal of improving weather prediction and scientists’ understanding of climate change.
Hyperspectral sensing from space is a powerful technique that delivers weather balloon-quality measurements on a global scale. Using infrared hyperspectral sensing, AIRS passively measures temperature and humidity. Just as in the visible spectrum, the infrared region consists of a rainbow of colors. Certain colors correlate with altitude, and the brightness of the color corresponds to temperature. Measuring the brightness at many colors permits full and accurate mapping of temperature from the surface to more than twenty miles in altitude. Humidity profiles are measured in a similar fashion.
Twelve individually optimized arrays, each consisting of 4,500 detectors, provide the system’s high wavelength selectivity and initial signal processing. For high sensitivity operation, the detectors are cooled to 58 Kelvin by a first-of-its-kind, space-qualified Stirling pulse tube cryocooler.
