Total electron content of the ionosphere at 310S, 1967-1974

The total electron content (TEC) of the ionosphere at 310S (geographic) has been calculated on the basis of Faraday rotation measurements made between September 1967 and January 1975 using geostationary satellites. The day-to-day, diurnal, seasonal and solar cycle variations of TEC are illustrated and discussed in relation to the maximum electron density of the F-layer, NMAX. A regression analysis is used to derive curves corresponding to fixed high and low levels of activity. The variations of slab thickness S = TEC/NMAX are also illustrated and discussed. The results overlap the observation periods of other published results and general agreement is found with these other results. (author)