Some Peculiarities in the Maximum Ionization Density of the F₂ Layer

ABSTRACT

In the course of analysis of data on f₀F₂ at different Indian ionospheric stations on 75°E meridian, two peculiarities have been observed. Firstly, for the equatorial stations showing the bite-out effect, the change in ionization between low and high sunspot activity at the hour of post-noon peak of f₀F₂ is much higher than the corresponding change at the hour of the pre-noon peak. Such an effect is not observed at middle latitude stations. Secondly, when the variation of f₀F₂ with sunspot number is considered, the linear relationship which is generally assumed to exist between the two, breaks down at high sun-spot numbers at certain hours of the day. The point at which the departure from linearity takes place depends on the local time and on latitude.

These effects appear to be due to abnormal increase in the thickness of the layer during high sunspot activity and meridional transport of ionization away from the equator in the evening hours.