Generalization of ionospheric tomography on diverse data sources: Reconstruction of the three-dimensional ionosphere from simultaneous vertical ionograms, backscatter ionograms, and total electron content data

An ionospheric reconstruction method is developed that is capable of simultaneously utilizing information from all possible sources of ionospheric measurement. We describe the method and demonstrate its performance on ionospheric data collected by an over-the-horizon radar (vertical and backscatter ionograms) and total electron content data collected by receivers operated in the Caribbean by the Applied Research Laboratories of the University of Texas at Austin. For each data set the method produces a smooth three-dimensional ionospheric model that is consistent with all the measurements. The method is based on the Newton-Kontorovich method for nonlinear operator equations and Tikhonov's regularization technique for ill-posed problems. We demonstrate here the ability of our technique to reconstruct ionospheric spatial variations from global-scale to medium-scale irregularities or traveling ionospheric disturbances. Overall results of this study demonstrate that the technique suggested makes it possible to unite data from various ionospheric instruments to provide monitoring of the ionosphere over a large geographical area in a wide range of spatial scales.