Book Description

In response to Air Force needs for specifying and forecasting conditions of the Arctic ionosphere, AFCRL's Airborne Ionospheric Laboratory, a highly instrumented NKC 135 jet aircraft, was used in an extensive Arctic research program that started in 1967. To date, 69 flights were made and ionospheric and optical data covering major parts of the auroral oval, mainly the midday sector and the night sector, were collected. During the winter months of 1967, 1968, 1969, and 1970 special emphasis was put on the investigation of the day sector. These flights covered a rather unique and poorly investigated area of the auroral oval, and a detailed report on the observations is given here. A thorough analysis of the data collected in the day sector reveals the existence of a band of continuous particle precipitation south of the location of the discrete aurora. This precipitation hardens towards the south and results in E- and D-region ionization. These observations compare very well with measurements of precipitating particles done by satellite. The investigation of the evening and night sectors showed similar but less organized trends than on the day side. During several flights the continuity of the auroral oval was verified. The investigation indicates that, with additional measurements, it may be possible to develop a model of the Arctic ionosphere. With control measurements from a few ideally located ground stations, the dynamics of the Arctic ionosphere might then be utilized for forecasting propagation conditions in the Arctic. (Author).