The dependence of ionospheric characteristics on the state of the solar-cycle

Abstract

A review on the solar-cycle dependence of the monthly median critical frequencies of the different ionospheric layers is attempted. Some of the existing questions are emphasized and the differing viewpoints are reported. Moreover, the correlations between daily values of the critical frequencies and solar activity indices are briefly considered and compared to those for monthly median values.

Keywords

• Ionosphere
• standard ionospheric characteristics
• radio wave propagation
• solar activity