A forward model for ionospheric soundings and its use with incoherent scatter radar data to obtain ionospheric plasma density profiles

In the probing of the valley region of the equatorial ionosphere (E-region and lower F-region) at the Jicamarca Radio Observatory (JRO) both the VIPIR (vertical incidence pulsed ionospheric radar) ionosonde and the 50 MHz Jicamarca incoherent scattering radar (ISR) are used. The ionosonde measures the plasma frequency of the ionosphere versus virtual height in the form of an ionogram, but the relation between virtual height and physical height is indirect. Our goal is performing the inversion of the ionogram to obtain the electron density profile of the ionosphere by processing the ionogram data jointly with the ISR data.

To solve the inverse problem, we built a forward model for the ionogram O- and X-traces recorded in the equatorial ionosphere geometry. A method for extracting the O- and X-traces from the raw ionograms and fitting them to the forward model was developed. This is carried out jointly with fitting the ISR Faraday rotation phase data by the same density profiles fitted to the ionogram traces.