Validation of Swarm Langmuir Probes by Incoherent Scatter Radars at High Latitudes

Electron density measured at high latitudes by the Swarm satellites was compared with measurements by the incoherent scatter radars at Resolute Bay and Poker Flat. Overall, the ratio of Swarm-based electron density to that measured by the radars was about 0.5-0.6. Smaller ratios were observed at larger electron densities, usually during the daytime. At low electron densities less than 3 x 10(10) m(-3), the ratios were typically above 1, indicating an overestimation effect. The overestimation effect was stronger at night and for Swarm B. It was more evident at lower solar activity when the electron densities in the topside ionosphere were lower.