1Finnish Meteorological Institute, Helsinki, Finland
2Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland
3Ionospheric Physics, University of Oulu, Oulu, Finland
4Department of Mathematics, Tallinn University of Technology, Tallinn, Estonia
5Haystack Observatory, Massachusetts Institute of Technology, Westford, MA, USA
Received: 26 Aug 2015 – Discussion started: 21 Sep 2015
Abstract. We validate two-dimensional ionospheric tomography reconstructions against EISCAT incoherent scatter radar measurements. Our tomography method is based on Bayesian statistical inversion with prior distribution given by its mean and covariance. We employ ionosonde measurements for the choice of the prior mean and covariance parameters and use the Gaussian Markov random fields as a sparse matrix approximation for the numerical computations. This results in a computationally efficient tomographic inversion algorithm with clear probabilistic interpretation.
Revised: 15 Mar 2016 – Accepted: 17 Mar 2016 – Published: 28 Apr 2016
We demonstrate how this method works with simultaneous beacon satellite and ionosonde measurements obtained in northern Scandinavia. The performance is compared with results obtained with a zero-mean prior and with the prior mean taken from the International Reference Ionosphere 2007 model. In validating the results, we use EISCAT ultra-high-frequency incoherent scatter radar measurements as the ground truth for the ionization profile shape.
We find that in comparison to the alternative prior information sources, ionosonde measurements improve the reconstruction by adding accurate information about the absolute value and the altitude distribution of electron density. With an ionosonde at continuous disposal, the presented method enhances stand-alone near-real-time ionospheric tomography for the given conditions significantly.
Norberg, J., Virtanen, I. I., Roininen, L., Vierinen, J., Orispää, M., Kauristie, K., and Lehtinen, M. S.: Bayesian statistical ionospheric tomography improved by incorporating ionosonde measurements, Atmos. Meas. Tech., 9, 1859-1869, doi:10.5194/amt-9-1859-2016, 2016.