A Regional Adaptive and Assimilative Three-Dimensional Ionospheric Model

An adaptive three-dimensional (3D) regional ionospheric model is proposed. It is able to ingest real-time data from different ionosondes, providing the ionospheric bottom side plasma frequency fp over the Italian area. The model is built using as basis empirical values over the considered region of a set of ionospheric parameters Pibase, to some of which has been assigned an increment Pi. Then, the values of the ionospheric parameters actually observed at a given time in a given site will be Pi= Pibase+Pi. These Pi values are used as input of an electron density N(h) profiler. The latter is derived from the Advanced Ionospheric Profiler (AIP), which is the software used by Autoscala as a part of the process of automatic inversion on the ionogram trace. The 3D-model ingests ionosonde data by minimizing the root-mean-square deviation between the observed and modeled values of fp(h) obtained from the N(h) associated ones, at the points where the observations are available. The Pi values are obtained through the minimization procedure. The 3D-model is tested adapting it with data collected at the ionospheric stations of Rome (41.8 N, 12.5 E) and Gibilmanna (37.9 N, 14.0 E) and using data from the ionospheric station of San Vito dei Normanni (40.6 N, 18.0 E) for comparison. The software developed is able to produce maps of critical frequencies foF2 and foF1 and of fp at fixed altitude, and transverse and longitudinal sections of the bottomside ionosphere, in scale of colors. fp(h) profiles of and associated simulated ionograms are easily producible for each geographic location of the Italian region. Values of fp within the considered volume can be also provided.