Browsing by Author "Gebremedihn, Asmelash"

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    Tomographic Imaging of Ionospheric Electron Density over Eastern Africa using Multi-Platform Instrumentations and Model Ionospheric total Electron Content
    (Addis Ababa University, 2013-06) Gebremedihn, Asmelash; Mengistu, Gizaw (PhD)
    A 3D - computerized tomography technique has been used to investigate the electron density of the low - latitude ionosphere during the low solar minimum in 2008 over the East Africa region. The 3D - tomography uses Damped Least Square inversion with the second order Tikhonove Regularization (DLSTR) algorithm. The TEC used in the tomographic inversion is obtained from the observables measured by a chain of station reciving transit satellite transmission over the region. The algorithm employes electron density from NeQuick model as apriori values. The electron density obtained from the inversion is a weighted combination of the apriori electron density and that obtaind from GPS measurement. The results show that the reconstructed electron density exhibits the required diurnal, latitudinal and longitudinal variations consistent with the physics of plasma formation and transport