An improved model of the variation of electron concentration with height in the ionosphere

An empirical model of the variation of electron concentration with height is described which overcomes some limitations found in practice with a previous widely used model (Bradley and Dudeney, 1973). In particular, the new model will generate more realistic variations of electron concentration with real height and virtual height, both including and excluding an F1-ledge. The model has no gradient discontinuities and will reproduce cases in which the F1-ledge does not have a true turning point. The model should prove very valuable for a wide range of propagation problems and for certain aeronomical applications.