Recent studies of the ionosphere

Abstract

Results of ionosphere measurements utilizing transmissions at vertical incidence and made weekly over a period of 18 months are discussed. Typical graphs of diurnal variations of the E-layer critical frequency and its relation to the ionizing for ce of the s un are shown for three seasons. Similar graphs for the F2layer are included a s well as a seasonal curve of midday , and maximum critical frequencies of this layer. The absence of midday F 2 critical frequencies during the summer is pronounced.

Radio exploration of upper-atmospheric ionization

“…Extensive valuable surveys of ionospheric conditions in America have been made by Schafer and Goodall (j4) ; by Gilliland(5j' ; by Kirby,Berkner and Stuart(j6) and by Kirby and Judson (57). I n all cases the critical frequency method of ionization measurement was adopted.…”

“…The work on Region F2 does not lead to correspondingly definite conclusions. Observations at Kingston (57) were interpreted as indicating a reduction of 30 per cent from normal ionization at totality. On the other hand, the corresponding observations at Washington(") did not show any optical eclipse effect, though the observers are of opinion that, due to absorption effects which cause region F, critical frequency measurements to be unreliable, the results did not preclude its occurrence, Observations at Deal, New Jersey, U.S.A."" also showed no changes of ionization which could be identified as an eclipse effect.…”

“…In connexion with these results and those of Ranzi, mentioned above, it may not be superfluous to recall the well-known connexion between thunderstorms and atmospheric depressions. Kirby and Judson (57) have made a study of abnormal Region E reflections in America and find no correlation between the occurrence of such ionization either with magnetic storms or with thunderstorms, the latter occurring either locally or within a radius of 300 km.…”