Study of Auroral Dynamics by Mean of Global Ground Networks

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In order to clarify dynamical aspect of temporally varying and spatially complex nature of aurora in the polar region, it is essential to get linked data set satellite observation from high altitude in the magnetosphere and ground-based multi-point observation. A global multi-station campaign to observe auroral dynamics was carried out to realize such coordinated observation in 1989-1990 winter time when Japanese research satellite "Akebono" had her apogee (-10000 km) high in latitude in the northern hemisphere.The main observation period was one month starting from 2nd week of January 1990, but at some limited sites early phase observations started December 21, 1989 and late phase ones were continued till the end of February 1990. In order to study dynamic aspect of global aurora and magnetic field disturbances in conjunction with AKEBONO observations, eleven of high sensitive all-sky TV cameras were operated in Alaska (1), Canada (7), Greenland (1), Spitzbergen (1) and Norway (1) at … More the respective number of sites in the parentheses. The global coverage and the continuity of field of view of those all-sky TV cameras were the most extensive one. All-sky images were recorded continuously with TV fram rate as long as weather conditions permitted. Magnetic measurements were made with fluxgate and induction magnetometers at 13 and 26 sites, respectively. Digital data of fluxgate magnetometer were acquired with time and amplitude resolutions of 1 sec and 125pT, respectively. Signal from induction magnetometers was recorded with digital data loggers (8bit compressed 10 Hz sampling) at selected 7 stations and with analog cassette recorders (FM, bellow・5Hz) at other sites.Cases of satellite-ground correspondence were surveyed for the foot print locus along the geomagnetic lines of force at the ionosphere whether they cross the view field of all-sky TV camera (circle of 1000 km radius) at each observation site. Combined with weather condition, 26 cases of correspondences were found.Multi-station observation is also a practical way to cover a weak point of optical observation strongly controlled by weather condition. Less