Harmonic analysis of the F2 critical frequencies at several Antarctic stations

Abstract

An harmonic analysis of the critical frequencies of the F2 region was performed on data from 12 stations in the Antarctic region, for the period July 1957–September 1969. The constant term from this analysis for each month was plotted against time and a significant difference was found in its pattern of behaviour before and after December 1960. This is attributed to the low level of solar activity during 1960–1966. There is an equinoctial maximum in the values of this constant term, which is particularly evident near sunspot maximum. An empirical equation is put forward which gives a good representation of the constant term for each station. It is shown that the average value of f 0 F2 under quiet solar conditions increases towards the south geographic pole.