NeXtYZ: Three-dimensional electron density inversion for dynasonde ionograms

[1] The problem of electron density inversion of digital ionograms is reconsidered from the viewpoints of new possibilities and of modern requirements. The data processing system of an advanced ionosonde (the dynasonde) provides accurate measurements not only of echo group range but also of direction of arrival, among other physical parameters, thus yielding the three-dimensional distribution of apparent echolocations in each ionogram recording. An iterative ray-tracing approach is described here to recover the parameters of a quite sophisticated three-dimensional (so-called wedge-stratified ionosphere) model of the local electron density distribution, characterizing its actual vertical Ne(h) profile together with horizontal gradients and general tilts. The power of a contemporary PC is sufficient to accomplish this analysis quickly. This approach is implemented in the algorithm introduced here, is named ‘‘NeXtYZ,’’ and is pronounced ‘‘next wise.’’