A method for the automatic calculation of electron density profiles from vertical incidence ionograms

摘要

Vertical incidence ionograms indicate ionospheric characteristics over the ionosonde station, from which electron density profiles can be derived. This paper describes a method for the automatic calculation of electron density profiles from vertical incidence ionograms. First, the method calculates the initial parameters of the quasi-parabolic segments (QPS) model by using the International Reference Ionosphere (IRI) model, the Nequiclk2 model, image processing techniques, and the Empirical Orthogonal Function (EOF). Once the initial parameters have been calculated the method then adjusts those to obtain the electron density profiles and synthesized traces that match the recorded ionograms. The algorithm then selects the best-fit synthesized trace and corresponding parameters as output from the candidate ones. Furthermore, the corresponding electron density profile of the recorded ionogram is calculated by using the best-fit parameters of the QPS model. To further test the feasibility of the proposed method, we apply it to some ionograms that were recorded at Wuhan during different seasons. As a result, our results demonstrate that the proposed method is feasible for the automatic calculation of electron density profiles.