OI 630 Airglow Observations in the Polar Ionosphere

Instruments operating in the polar caps through the past solar cycle have provided much new information on the structure and dynamics of the polar ionosphere. Digital ionosondes at several stations have yielded electron density profiles and f_o}F{2 variations. Photometers monitoring [O] night airglow emissions over Eureka, Nanavut (80⁰ N), have given a complementary view of the ionosphere. The 630 nm emission intensity is seen to be directly related to the f_o}F{2 obtained from a CADI ionosonde operated at Eureka. We will report on the variations of these parameters through the past solar cycle, drawing on observations through each winter since 1991 from this site near the North Magnetic Pole. [O] emission intensities even under quiet conditions are seen to vary over a factor of ten or more through the solar cycle. During much of the time the airglow is enhanced by either polar auroras or F-layer patches (depending on the sign of the IMF B_z).