Case study of polar cap scintillation modeling using DE 2 irregularity measurements at 800 km


  • Sunanda Basu,

  • Santimay Basu,

  • E. J. Weber,

  • W. R. Coley


Although a satellite-borne irregularity sensor obviously cannot measure scintillations, we address the question of what contribution such a sensor can make to model or predict scintillations. To pursue the problem, we have utilized the Dynamics Explorer 2 (DE 2) ionospheric electron density irregularity data obtained at approximately 800 km altitude in the winter polar cap during sunspot maximum conditions. During this period an all-sky imaging photometer located at Thule, Greenland, within the polar cap, detected the presence of convecting ionization patches, and polar beacon satellite measurements detected several discrete, intense scintillation structures associated with these patches (E. J. Weber et al., 1984). The electron density deviation (ΔN) obtained by combining irregularity amplitudes (ΔN/N)rms processed over successive 8-s intervals and the in situ density (N) data acquired by the DE 2 satellite also showed the presence of spatially discrete structures. These irregularity structures, both in N and ΔN, had spatial extents of ∼1000 km in the N-S direction. The density associated with these structures, even at 800 km, showed a twofold to threefold increase in comparison to the background, and irregularity amplitudes (ΔN/N)rms as large as 20% were observed at the edges of the patches. It is shown that the observed scintillation parameters can be successfully modeled only when the satellite sensor irregularity data are combined with additional and vital information regarding maximum ionization density, irregularity anisotropy, and layer thickness in the framework of scintillation theory. We conclude that within the context of other measurements and an appropriate scintillation model, the irregularity sensor data may serve as a valuable input.