Reconstruction of topside ionosphere scale height from coordinated GPS-TEC and ionosonde observations

The vertical total electron content (TEC) derived from the data of the Global Positioning System (GPS) is used for reconstruction of topside ionosphere scale height with the ISO_IRI model (the project of the International Organization for Standardization based on the International Reference Ionosphere extended towards the plasmasphere). The ionosonde derived F2 layer peak density (NmF2) and height (hmF2) ensure true electron density maximum at the F2 peak. Topside electron density profile is expressed with complementary half- peak density anchor height above hmF2. GPS-TEC measurements during the solar minimum (1995-1996) and solar maximum (2002-2003) for quiet and disturbed magnetic conditions are used to produce the topside scale height. Mapping of the F2 layer peak parameters and TEC allows to interpolate these parameters at coordinated grid sites from the independent GPS and ionosondes networks. The analysis revealed an expanding ionosphere during the magnetic storm with peaks of the scale height exceeding 800 km during the peak of the magnetic storm by nighttime at middle and high latitudes.