Some regularities in theF2 region of the ionosphere

Abstract

A quick and approximate method was used to analyse (h′ ‐ f) records of radio waves reflected from the ionosphere so as to give the total number (n) of electrons below the level of maximum electron density in a column of unit cross‐section in the F2 region. The, analysis was carried out on records obtained at Watheroo (Australia), Huancayo (Peru), and College (Alaska) for two magnetically quiet days per month in a year of sunspot maximum and a year of sunspot minimum. It was found that the quantity n was closely related to the zenith angle (χ) of the sun's rays, whereas it is well known that the maximum electron density Nm in the F2 layer is not simply related to this angle. The well‐known anomalies which are apparent when Nm is studied as a function of time of day, time of the year, and geographical position, all seemed to disappear when the quantity n was studied instead. A new kind of anomaly which was observed at Huancayo in years of sunspot minimum is described and discussed. A relation between the thickness and the height of the F2 layer is established and the possibility of using it in ionospheric forecasting and theory is discussed. Since the deductions of this paper are made on data from only three stations, it is suggested that a similar analysis should be made for other stations. This is all the more necessary because two other sets of workers have reported results in disagreement with those obtained in this paper.

The Structure of the F Region of the Ionosphere

“…strongly dependent upon height, with a normal Chapman region and failure of bifurcation to appear. Some additional mechanism, such as tides, woul<i probably be necessary to account for the major seasonal alterations in thedistribution of electrons within the F II region, as reported by Ratcliffe (1951). This explanation is consistent with the results of Smith (1952), who from. studies of the refraction of radio stars at Cambridge has found that the integra.ted electron density above h";, is normal for a Chapman region in winter and whilst.…”

Stratification of the Low-Latitude and Near-EquatorialF2Layer, Topside Ionization Ledge, andF3Layer: What We Know about This? A Review

“…In the South American region, Ratcliffe [4] observed an addition layer in h F records from Huancayo (12.1…”

Features of the F3 layer occurrence over the equatorial location of Trivandrum

“…The appearance of an additional ionization layer above the F2 peak is an example of the aforesaid equatorial features. The additional stratification of the F2 layer over low and mid latitudes was known as early as the 1940s (Sen, 1949;Ratcliffe, 1951;Skinner et al, 1954;Heisler, 1962), though the stratification could not be explained. These investigators attributed the traveling disturbances and dynamics involving vertical ionic drifts as the possible sources of these stratifications.…”