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The Atmospheric Infrared Sounder (AIRS) is one of six instruments flying on board NASA’s Aqua satellite, launched on May 4, 2002. The instrument is designed to support climate research and improve weather forecasting.〔(【引用サイトリンク】 title =AIRS Mission Objectives )〕 Working in combination with its partner microwave instrument, the Advanced Microwave Sounding Unit (AMSU-A), AIRS observes the global water and energy cycles, climate variation and trends, and the response of the climate system to increased greenhouse gases. AIRS uses infrared technology to create three-dimensional maps of air and surface temperature, water vapor, and cloud properties. AIRS can also measure trace greenhouse gases such as ozone, carbon monoxide, carbon dioxide, and methane. AIRS and AMSU-A share the Aqua satellite with the Moderate Resolution Imaging Spectroradiometer (MODIS), Clouds and the Earth's Radiant Energy System (CERES), and the Advanced Microwave Scanning Radiometer-EOS (AMSR-E). Aqua is part of NASA's "A-train," a series of high-inclination, Sun-synchronous satellites in low Earth orbit designed to make long-term global observations of the land surface, biosphere, solid Earth, atmosphere, and ocean.〔(【引用サイトリンク】 title =Aqua and the A-Train )〕 AIRS data is free and available to the public through the Goddard Earth Sciences Data Information and Services Center.〔(【引用サイトリンク】 NASA Goddard Earth Sciences Data and Information Services Center )〕 NASA's Jet Propulsion Laboratory in Pasadena, California, manages AIRS for NASA's Science Mission Directorate in Washington, D.C. ==Technology== The term "sounder" in AIRS's name refers to the fact that the instrument measures temperature and water vapor as a function of height. AIRS measures the infrared brightness coming up from Earth's surface and from the atmosphere. Its scan mirror rotates around an axis along the line of flight and directs infrared energy from the Earth into the instrument. As the spacecraft moves along, this mirror sweeps the ground creating a scan swath that extends roughly 800 kilometers on either side of the ground track. Within the instrument, an advanced, high-resolution spectrometer separates the infrared energy into wavelengths. Each infrared wavelength is sensitive to temperature and water vapor over a range of heights in the atmosphere, from the surface up into the stratosphere. By having multiple infrared detectors, each sensing a particular wavelength, a temperature profile, or sounding of the atmosphere, can be made. While prior space instruments had only 15 detectors, AIRS has 2378. This greatly improves the accuracy, making it comparable to measurements made by weather balloons. Thick clouds act like a wall to the infrared energy measured by AIRS. However, microwave instruments on board Aqua can see through the clouds with limited accuracy. Using a special computer algorithm, data from AIRS and the microwave instruments are combined to provide highly accurate measurements in all cloud conditions resulting in a daily global snapshot of the state of the atmosphere.〔(【引用サイトリンク】 title =How AIRS Works )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Atmospheric Infrared Sounder」の詳細全文を読む スポンサード リンク
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