DETERMINATION OF THE VERTICAL ELECTRON-DENSITY PROFILE IN IONOSPHERICTOMOGRAPHY - EXPERIMENTAL RESULTS

The reconstruction of the vertical electron-density profile is a funda mental problem in ionospheric tomography. Lack of near-horizontal ray paths limits the information available on the vertical profile, so tha t the resultant image of electron density is biased in a horizontal se nse. The vertical profile is of great importance as it affects the aut henticity of the entire tomographic image. A new method is described w hereby the vertical profile is selected using relative total-electron- content measurements. The new reconstruction process has been develope d from modelling studies. A range of background ionospheres, represent ing many possible peak heights, scale heights and electron densities a re formed from a Chapman profile on the bottomside with a range of top side profiles. The iterative reconstruction process is performed on al l of these background ionospheres and a numerical selection criterion employed to select the final image. The resulting tomographic images s how excellent agreement in electron density when compared with indepen dent verification provided by the EISCAT radar.