Initial results of imaging riometer observations at polar cap conjugate stations

概要

論文の詳細を見る
Geomagnetically conjugate observations using a newly installed imaging riometer at Zhongshan (74.7°S geomag. lat.), Antarctica and the existing imaging riometers at Ny-Ålesund/Longyearbyen 〜76°N, geomag. lat.), Svalbard, started in January 1997 for studying conjugate characteristics of cosmic radio noise absorption (CNA) in the high-latitude ionosphere. Examples of nighttime ionospheric absorptions observed at the conjugate stations are presented for strong and weak geomagnetic disturbances in the polar region. Conjugate characteristics of total 30 nighttime absorption events during initial two-week observations are investigated in relation to the ground geomagnetic activities, and also discussed about the effect of the interplanetary magnetic field (IMF), in comparison with the conjugate points calculated by Tsyganenko-96 magnetic field model. The following characteristics are described : (1) Simultaneous absorptions are observed between the conjugate stations more preferentially on the strong geomagnetic disturbances. (2) The shape and movement of small-scale absorption (50-100km) are considerably different, even if large-scale absorption (>100km) shows a similar aspect between the conjugate stations. (3) On weak geomagnetic disturbances, absorptions are mostly observed at a station in one hemisphere only; they may be conjugate or non-conjugate.
国立極地研究所の論文