Ionospheric electron content and its variations deduced from satellite observations

A procedure is given for correcting the effect of refraction and the high-frequency approximation when Faraday rotation measurement is available on two frequencies. This method is used to analyze the records obtained on the ground of radio transmissions from satellite 1958 δ2 (Sputnik III). The result reveals strong diurnal as well as anomalous seasonal variations. The depression in electron content during magnetic storms is identified, and the preliminary observational result is not inconsistent with the drift theory.