Analysis of simultaneously recorded 1.5‐ and 4‐GHz scintillations at Tangua, Brazil, has shown that the scintillation index varies approximately as the wavelength between 1.5 and 4 GHz under weak scattering conditions. The amplitude distributions, especially those of the 1.5‐GHz data, are somewhat irregular in shape and cannot be represented by a simple mathematical expression. The power spectra of the amplitude fluctuations on a log‐log plot show a slope of −3 and have low wave number rolloffs near 10−2 m−1. This paper discusses some possible implications of these findings. Half of the 4‐GHz power spectra show the minima which are predicted by the thin‐screen weak scattering theory. The l/e falloff of the autocorrelation corresponds to irregularities between 100 and 200 m. The cross correlation between the 1.5‐ and 4‐GHz scintillations is about 0.3.

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Sporadic‐E (ES) data from Japan were presented to show the temporal variations in sporadic‐E blanketing frequency (ƒbES), virtual height (h′ES), and frequency of occurrence. Tidal winds were substituted into the wind‐shear theory of ES to calculate electron density profiles and determine the influence of the tidal winds in the asymmetry of the ES occurrence variation. Results showed that the tidal wind model used was not strong enough to significantly influence the formation of molecular ion ES layers, but that the winds did have the proper orientation to accumulate and layer metallic ions in the late afternoon. The role of metallic ions in afternoon ES will have to be established.

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