Catalog of auroral radio absorption during 1976-1979 at Abisko, Sweden

"This catalog lists concisely radio absorption events recorded by the wide-beam 30-MHz riometer at Abisko, Sweden, during the International Magnetospheric Study (IMS) of 1976-1979. The station has geographic coordinates N68.36° and E18.8° and an L value of 5.64 (invariant latitude 65.1°); magnetic midnight occurs there about 2200 UT. The detector is a standard La Jolla Sciences riometer with additional output smoothing to increase the response time to a few seconds. The antenna comprises two wire dipoles over reflector wires, producing a beam pointed to the zenith and having an approximately circular response pattern in which the gain decreases 3 dB at zenith angle 32° [Ecklund and Hargreaves, 1968]. Quoted absorption values remain uncorrected for antenna beam width; they should be reduced about 30% to obtain the absorption that a pencil beam antenna pointed to the zenith would measure. The catalog should be useful in three ways: (1) to indicate the level of auroral absorption activity in Scandinavia at particular times or on particular days; (2) to study statistically the incidence and intensity of radio absorption events; and (3) to aid in the selection of events of a particular type for detailed study"--Introduction. by J.K. Hargreaves, C.M. Taylor, and J.M. Penman. At head of title: World Data Center A for Solar-Terrestrial Physics. "July 1982." Also available online in PDF form. Includes bibliographical references (page 3). 1982 NESDIS (National Environmental Satellite, Data, and Information Service) Library Public Domain 2286