Ionospheric sporadic-e parameters: long-term trends.
The results of observations over 3(1/2) solar cycles of ionosonde parameters describing sporadic-E patches (E(s)) are given for two Southern Hemisphere stations. Analysis has revealed systematic changes in the occurrence probabilities of f(o)E(s) and f(b)E(s), changes that are independent of time of day or season. It is unlikely that observational effects can be entirely responsible for the trends, which suggest that major long-term changes may be occurring at E region heights.
Baggaley
W J
WJ