Sporadic structures in the equatorial ionosphere inferred from radio occultation data on satellite-to-satellite paths

We analyze characteristics of sporadic layers in the equatorial ionosphere using the results of radio occultation sounding on the paths between GPS satellites and the CHAMP low-orbiting satellite during the solar flare in October–November 2003. Variations in the amplitude and phase of signals during the lower-ionosphere sounding are studied. It is shown that the use of amplitude and phase data allows one to obtain parameters of the sporadic ionospheric structures. The data on the occurrence frequency, height, thickness, and intensity of the E_s layers in the daytime and nighttime equatorial ionosphere are presented. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 3, pp. 181–190, March 2008.     

Lower polar ionosphere during a solar flare as revealed from radiooccultation data in satellite-to-satellite links

It is shown that there are typical variations in the amplitude and phase of decimetric radio waves in satellite-to-satellite links due to variations in the polar ionosphere structure. The altitude profiles of the electron number density and vertical size of the ionospheric sporadic structures in the nighttime polar regions during the period of intense solar activity in October 25 to November 09, 2003 are estimated. Correlation between the the ionosphere characteristics and the solar-wind parameters is discussed. It is noted that the effect of energetic-particle precipitation due to the influence of shock waves of the solar wind is the main factor responsible for strong variations in the nighttime polar ionosphere. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 52, No. 3, pp. 181–191, March 2009.     

Results of Studying the Daytime Polar Ionosphere by the Radio Occultation Method on Satellite-To-Satellite Paths

Radiophysics and Quantum Electronics - We analyze specific features of the radio occultation method and the possibility of using it to study the altitude profiles of electron density and the...     

The Structure of Stratospheric Irregularities According to Radio-Occultation Data Obtained using Satellite-to-Satellite Paths

We analyze the possibility of monitoring density or temperature fluctuations in the stratosphere based on data of amplitude radio-occultation measurements at centimeter waves using satellite-to-satellite paths. Comparison of the experimental spectra of amplitude fluctuations with the theoretical spectra calculated for a model containing both strongly anisotropic irregularities and an isotropic Kolmogorov turbulence shows that the amplitude fluctuations of radio waves in the stratosphere are mainly contributed by anisotropic irregularities which correspond to the model of saturated internal gravity waves. The efficiency of the radio occultation technique for the global remote monitoring of internal waves in the stratosphere is demonstrated.     

Radiowave fluctuations in the polar ionosphere on the satellite-to-satellite paths under high solar activity

We analyze ionospheric fluctuations of decimeter radio waves on occultation polar paths between the navigational GPS satellites and the satellite CHAMP. Time dependences of the variance of the signal amplitude and amplitude fluctuation spectra under high solar activity in October–November 2003 are presented. The behavior of the signal amplitude fluctuations during occultation ionospheric sounding in the polar regions in different time of the day and in the equatorial regions in the daytime are considered. Radio-wave fluctuations are related to the solar-activity manifestations. It is shown that during strong solar-flare activity, intense small-scale plasma irregularities are excited in the polar ionosphere. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 3, pp. 185–193, March 2006.