Polar airglow and aurora.

A survey of night airglow emissions in the polar cap shows stable emission intensities during quiet periods through the winter solstice. Those affected by particle precipitation, O I λ5577 and λ6300, show great variability with solar activity and the state of the interplanetary magnetic field. A statistical study of electron-precipitation occurrence above 78° geomagnetic latitude shows events sufficient to result in observable enhancements in O I emission intensities in about 40% of the satellite passes in the magnetic latitude range from 79° to 83° and in about 15% of the passes for latitudes above 85°.