Bayesian statistical ionospheric tomography improved by incorporating ionosonde measurements

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 p...

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Bibliographic Details
Published in:Atmospheric Measurement Techniques
Main Authors: J. Norberg, I. I. Virtanen, L. Roininen, J. Vierinen, M. Orispää, K. Kauristie, M. S. Lehtinen
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2016
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Online Access:https://doi.org/10.5194/amt-9-1859-2016
https://doaj.org/article/e97e1094c99e4da4bed572f37d928b33
Description
Summary: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. 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.