Airglow DataIt has been described as a permanent aurora or the light other than the polar aurora, emitted by the upper atmosphere (C.T. Elvey, 1950). During daylight, the solar ultraviolet rays ionize oxygen, nitrogen, and other molecules in the upper atmosphere. These molecular fragments then recombine at night, emitting mostly in a faint green light. At solar minimum when solar activity is reduced, the airglow dims significantly. Airglow occurs in the lower thermosphere and upper mesosphere and can measure changes in the ionosphere and middle atmosphere. While it is usually too faint for the human eye to see, instrumentation, like photometers, can measure the night airglow. NCEI holds data taken during the International Geophysical Year (IGY) 1957-59 and the International Quiet Sun Year (IQSY) 1964-65 for the hourly zenith intensities of ionized Oxygen OI 557.7 nm (green), Sodium Iodide NaI 589.0-9.6 nm, and ionized Oxygen OI 630.0 nm (red), plus some observations of hydroxyl (OH) and ionized Nitrogen N2+ 391.4 nm. These data can be compared with recent observations to determine global change effects. Airglow is extemely sensitive to global change. The darkness of the night sky is affected by 1.) airglow, 2.) light scattered while passing through the atmosphere, 3.) sunshine reflected off dust particles orbiting between the sun and Jupiter (zodiacal light) and 4.) glimmering caused by swarms of faraway stars (Milky Way) -- see Sky Lights by Bob Berman, Discover Magazine, April 2005 issue. Data Documentation
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