On the Ionization of the F2Region

In this paper the available data on F
2
region ionization for Peru, Australia, and this country are analyzed in a way that permits the separation of effects due to variations in solar ionizing force from effects due to seasonal and annual changes. It is shown that for constant solar activity the expected curves of critical frequency for Australia and this country appear to indicate both seasonal and annual tendencies. It is suggested as a possibility that the apparent "annual" effect may in fact be due to meteorological conditions which cannot be eliminated without data from more locations.