Tomographic reconstruction of ionospheric electron density with European incoherent scatter radar verification

A campaign was conducted in late September 1991 to obtain experimental measurements for use in ionospheric tomography. Four stations receiving signals from the Navy Navigation Satellite System satellites were set up in a meridional chain in Scandinavia covering some 10° of latitude. Measurements of total electron content were made for six satellite passes over a 2‐day period coinciding with an extended run of the CP3f latitudinal scan common program of the European incoherent scatter radar. A new reconstruction technique involving the use of two‐dimensional basis vectors has been used to convert the total electron content measurements to images of electron density in a height versus latitude plane. Comparisons of the tomographic images and the independent measurements of electron density from the radar show good general agreement. Broadly similar troughs and enhancements are observed by the two techniques, and a latitudinal gradient in the height of the peak density is reproduced in both data sets.