A study of the noon critical frequencies of the E and F1 layers of the ionosphere

Abstract

The mean monthly noon critical frequencies of the E and F1 layers of the ionosphere at a number of stations in different latitudes and their variation with sunspot number have been studied in this paper. It is found that while theE layer approximates to a chapman region, the F1 layer is markedly affected by other agenices, somewhat similar to F2. In high sunspot years, ƒoF1 shows two maxima at middle latitudes with a minimum at the equator.