Some indices of solar activity based on ionospheric and radio noise measurements

Derivation and test of ionospheric activity indices from real-time ionosonde observations in the European region

“…However, in the middle of the last century first steps have been done to create ionospheric indices deduced from ionosonde observations. The index IF 2 has been derived from noon foF 2 observations at three stations (Minnis, 1955;Minnis and Bazzard, 1959). This index was later improved by using data from 11 stations (Minnis and Bazzard, 1960).…”

Ionospheric index of solar activity based on the data of measurements of the spacecraft signals characteristics

“…Instead of using the (Minnis, 1955, Minnis andBazzard, 1959) procedure of determining the IISA, it is possible to take advantage of the relation between an electronic concentration (Ne) and SA (W or F10:7), already established for a large experimental base of the ionospheric data (more than ÿve Solar cycles). This relation is included in the empirical and/or hybrid ionospheric models Ne(r; t) = M (r; t; W ), where the index of the SA (sun-spots number W and/or radio emission ux of the Sun F10:7) is introduced as an input parameter.…”

“…Because of this, there are signiÿ-cant errors in the evaluation of the ionospheric conditions at short-term prediction. For the sake of short-wave propagation, a new ionospheric index of solar activity (IISA) e ects was proposed (Minnis, 1955;Minnis and Bazzard, 1959;Turner, 1968;Nusinov and Ostrovsky, 1990). It is based on the relationship between f0F2 versus sunspot number observed over several solar cycles and re ects general ionospheric conditions.…”