Attenuation and scintillation of radio waves in the Earth's atmosphere from radio occultation experiments on satellite‐to‐satellite links

Abstract

A theoretical analysis of refractive loss of radio waves by the Earth's atmosphere in radio occultation measurements along the satellite‐to‐satellite line for various altitude profiles of the refractive index is given. Experimental results for refractive loss on the orbital spacecraft ‐ geostationary satellite link are presented. Theoretical calculations are compared with experimental data, and a conclusion is drawn that the signal amplitude during radio occultation is strongly dependent on the layered structure of the refractive index profile. Amplitude scintillations of centimeter (λ1 = 2 cm ) and decimeter (λ2 = 32 cm ) radio waves used in radio occultation experiments are described. Dependences of the rms value of the amplitude scintillations versus the minimum altitude of the ray line for the two above wavelength bands are presented. The frequency spectra of the log‐amplitude scintillations are analyzed together with the dependence of the rms amplitude on the wavelength. Experimental data are compared to the theory of scintillations in a turbulent atmosphere, and the altitude model of the structure constant of refractivity fluctuations is determined.

Scintillations of centimeter waves and the atmospheric irregularities from radio occultation data

“…The detection of the regularities of the radio scintillation changes during the occultation, depending on atmospheric state, height, location, time, and so on, will extend the understanding of creation processes of atmospheric inhomogeneities. A preliminary analysis of the amplitude scintillations in radio occultation experiments has been carried out by Yakovlev et al [1995b], who showed the possibility of studying the turbulence and atmospheric stratified structure.…”

“…[2] In order to find out the possibilities of the radio occultation method for monitoring the Earth's atmosphere, experimental research on decimeter and centimeter radio wave propagation from orbital station MIR to a geostationary satellite has been carried out in Russia between 1989 and 1998 [Vilkov et al, 1993;Matyugov et al, 1994;Yakovlev et al, 1995aYakovlev et al, , 1995b. In the United States, since 1995 the satellite Microlab-1, receiving decimeter radio waves emitted by GPS satellites, has been used to refine this atmospheric research technique [Ware et al, 1996;Kursinski et al, 1996Kursinski et al, , 1997Mortensen and Høeg, 1998].…”

Radio Wave Propagation Phenomena from GPS Occultation Data Analysis

“…The differences at the initial height of splitting can be related to slow variations in the radio signal amplitude. The existence of splitting is probably a signature of the presence of small, but tangible integral atmospheric absorption, whose magnitude is, on the average, close to the values mentioned in [21] and to the magnitude 0.0096  0.0024 dB/km of absorption per unit length measured in [12,13,22] The introduced method is a perspective tool for investigation of seasonal and annual variations and geographical distributions of the total absorption from RO data. Also this method is, possibly, may be applied to study the influence of the tropical hurricanes and typhoons on the altitude profiles of water vapor in the stratosphere and tropopause.…”

“…To obtain basic relationships describing the radio wave propagation in a spherically symmetric medium it is necessary to use a formula [18] for electromagnetic field E in an inhomogeneous medium that follows from Maxwell equations: 22 …”

Simultaneous observation of the vertical gradients of refractivity in the atmosphere and electron density in the lower ionosphere by radio occultation amplitude method

“…[2] Practical testing of the RO method began in 1989 using telecommunication line between the orbital station ''MIR'' and geo-stationary satellites (MIR/GEO) at wavelengths of 2 and 32 cm [Yakovlev et al, 1995]. A satellite known as ''Microlab-1'' was launched into Low Earth Orbit (LEO) for the RO GPS/MET experiments with highprecision GPS radio navigational signals in the two coherent frequency bands F1 = 1575.42 MHz and F2 = 1227.6 MHz.…”