The solar-cycle variation of M(3000)F2 and its correlation with that of f0F2

Abstract

Using hourly monthly-median measured values from nine long-standing ionospheric sounding stations with data sets extending over several decades, best-fit empirical relationships are established for M (3000)F2 with different solar and ionospheric indices representative of state of the solar cycle. The statistical analysis shows that there is no difference in the degree of correlation in using one index over another. Comparisons are also made with similar relationships for monthly median f0F2 determined from the corresponding measurement data sets and the degree of correlation between the two ionospheric parameters is established.