Ionosphere dynamics

Early studies of the ionosphere assumed that isoionic surfaces were substantially horizontal and smooth, and diurnal, seasonal and sunspot variations were worked out on that basis. In recent years, the attention of research workers has turned more and more to the study of irregularities and movements in ionization. Irregularities examined range in size from the order of hundreds of kilometers to tens of meters and apparent speeds of movement also show a wide variation. Examination reveals that many apparent discrepancies in results reported by different workers can be explained as the result of selectivity in acquisition of data due either to the widely varying methods of observation used, or to temporal or spatial variations in conditions observed. Recent observations with a high speed ionosonde, and recordings of signals from earth satellites are throwing new light on these phenomena, which at first may seem to increase the complexity, but on closer examination are tending to clarify results and point out methods of attack on the unresolved problems.