Experimental ionospheric tomography with ionosonde input and EISCAT verification

Results are presented of tomographic images of ionospheric electron density obtained from experimental measurements of total electron content at a linear chain of stations. Comparison with independent measurements made using a special scan or the EISCAT incoherent scatter radar show broad agreement except under extreme ionospheric conditions. The large-scale horizontal features of the electron density are replicated well in the tomographic image. The vertical profile is dependent on the ionospheric model used to create the background ionosphere formed as an initial condition in the reconstruction process. The inclusion of additional independent information in the form of the electron density and height of the layer peak obtained from ionosondes, has been incorporated into the imaging procedure. The resultant tomographic images show improved agreement with the EISCAT measurements in the vicinity of the layer maximum