Simultaneous 1.5‐ and 4‐GHz ionospheric scintillation measurement

Abstract

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.