Correction to: Medium-scale traveling ionospheric disturbances by three-dimensional ionospheric GPS tomography

Abstract

An amendment to this paper has been published and can be accessed via the original article.

Model-free approach for regional ionospheric multi-instrument imaging

“…Ultimately the iterative methods are solvers for linear systems where the initial value and stopping criterion have regularising effect for ill-posed systems. With regularised least squares methods (Kaipio & Somersalo, 2005), the linear system can be solved with more explicitly stated regularising information, typically by constraining gradients and requiring smoothness from the reconstructed electron density (Markkanen et al, 1995;Seemala et al, 2014;Song, Hattori, Zhang, Liu, & Yoshino, 2021;C. H. Chen et al, 2016).…”