Modification of the IRI Electron Density Profile from an Observation Ionogram Using the Full Wave Method in the Lower Ionosphere

As the International Reference Ionosphere (IRI) is very useful, the difference between the IRI profile and the actual profile must be checked constantly. For the electron density profile, ionograms are effective data to know the actual lower ionospheric conditions. Now, only special data such as foE and foF2 are used in the ionogram information, though the ionograms have much information of both apparent heights and reflection coefficients on observation frequencies. We suggest a method that estimate the delay time from both the electron density profile and the collision frequency profile by the full wave calculation. In this paper, we investigate difference between the measured ionogram and the IRI theoretical ionogram for one example. And we modify the IRI electron density profile so that the calculated ionogram fit to the measured ionogram.