Amplitude scintillation spectra and statistics obtained simultaneously at VHF (257.55 MHz), L band (1541.5 MHz), and C band (3945.5 MHz) from the MARISAT communications satellite (15°W) are presented. The measurements were made at Ascension Island (7°58′S, 14°25′W, 30°S DIP) over a high elevation propagation path within a few degrees of the magnetic meridian plane. The multi‐frequency data and the unique propagation geometry enable us to study the structures of the equatorial ionospheric irregularities closely. Numerical simulation is used to model a specific event. Comparisons between the modeling results and the observations indicate that the data are consistent with the recently measured (in situ) two‐component power law irregularity spectrum with a shallow large‐scale regime and a steeper small‐scale regime, and a spectral break at about 1‐km scale size.
Analytical and numerical techniques are used to model multifrequency amplitude scintillation data recorded in the equatorial region at Ascension Island. In particular, the behavior of the temporal coherence interval of multifrequency amplitude scintillation recorded at VHF, L band and C band is studied. The data cover a wide range of perturbation strengths corresponding to scintillation indices (S4) in the range 0.05–0.25 at C band (4 GHz). The dependence of the 50% decorrelation interval of the amplitude fluctuations on wave frequency and scintillation intensity is compared to analytical and numerical simulation results that are computed using a phase screen model. The observations are found to agree closely with simulated scintillation generated using a two‐component power law spectrum model for the ionospheric irregularities. A simple inverse relationship is found to exist between the correlation interval of saturated scintillations at VHF and the perturbation strength as measured by the C band scintillation index. The result is shown to be consistent with analytical results based on an asymptotic approximation to the covariance function for intensity scintillations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.