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A comparison of reconstruction techniques used in ionospheric tomography
Author(s) -
Pryse S. E.,
Kersley L.,
Mitchell C. N.,
Spencer P. S. J.,
Williams M. J.
Publication year - 1998
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/98rs01613
Subject(s) - a priori and a posteriori , ionosphere , incoherent scatter , radar , total electron content , tomography , algorithm , inverse problem , tomographic reconstruction , range (aeronautics) , computer science , inverse , iterative reconstruction , grid , remote sensing , computational physics , physics , mathematics , optics , geology , geophysics , geodesy , mathematical analysis , geometry , computer vision , aerospace engineering , telecommunications , philosophy , engineering , epistemology , tec
This paper compares the performance of three different reconstruction algorithms used for tomographic imaging of the ionosphere. The test cases chosen make use of experimental electron content observations obtained from a meridional chain of receivers in Scandinavia at times when the European incoherent scatter radar facility provided independent measurements of electron density for verification of the reconstructions. The examples include ionospheres with layers peaking at both anomalously high and very low altitudes, in addition to a smooth horizontally stratified layer. The results expose the limitations of an algorithm based on use of a standard ionospheric model but demonstrate that with appropriate choice of background a priori profiles, reliable images are obtained from both discrete inverse theory and quadratic programing. For these two latter algorithms the resultant reconstructions are essentially independent of the algorithm used. The study highlights the critical role of the range of the background input to the algorithms. A density value at a single grid cell provides sufficient additional a priori information to constrain the imaging of a horizontally stratified ionosphere.