Stellar scintillations in spacecraft occultation experiment for atmospheric irregularities with variable anisotropy

Abstract

The properties of stellar scintillations are studied in an occultation experiment during synchronous sounding of the atmosphere at different wavelengths. The scintillation auto and coherence spectra are calculated for the model of three-dimensional (3D) spectrum of atmospheric irregularities with variable anisotropy. In the calculations, we used the dependence of the anisotropy coefficient on the irregularity scale derived from chromatic stellar scintillation measurements with fast GOMOS (Global Ozone Monitoring by Occultation of Stars) photometers in tangential occultations. Calculations are carried out in approximations of the equivalent phase screen and weak scintillations. The regime of weak scintillations for low-orbit satellites corresponds to altitudes of ray perigee above 25–30 km. The scintillation spectra are compared for models of 3D spectrum of atmospheric irregularities with variable and constant anisotropy, and their common parameters and features are found.