University of Oulu

Madelaire, M., Laundal, K., Gjerloev, J., Hatch, S., Reistad, J., Vanhamäki, H., et al. (2023). Spatial resolution in inverse problems: The EZIE satellite mission. Journal of Geophysical Research: Space Physics, 128, e2023JA031394.

Spatial resolution in inverse problems : the EZIE satellite mission

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Author: Madelaire, Michael1; Laundal, Karl1; Gjerloev, Jesper1,2;
Organizations: 1Birkeland Centre for Space Science, University of Bergen, Bergen, Norway
2Johns Hopkins University Applied Physics Laboratory, Laural, MD, USA
3Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
4School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW, Australia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.8 MB)
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Language: English
Published: American Geophysical Union, 2023
Publish Date: 2023-08-18


Inverse modeling has become one of the primary methods for studying ionospheric electrodynamics, especially when using magnetic field measurements from below the ionosphere. We present a method for quantifying the spatial resolution in an inverse model for non-uniformly sampled spatial data. This method provides a tool for assessing if a model can resolve the physical phenomena of interest. We quantify the spatial resolution for the Spherical Elementary Current System basis functions to model the ionospheric dynamics. Our results apply to models with spatially confined model parameters, unlike spherical harmonics where the model parameters describe the amplitude of global surface functions. The method is demonstrated for the upcoming Electrojet Zeeman Imaging Explorer cubesat mission which will provide spatially distributed remote sensing measurements of the magnetic field in the mesosphere. We show that, including measurements from a single ground magnetometer can significantly improve the spatial resolution. However, the impact of including a ground magnetometer depends on the relative position of the station with respect to the mesospheric measurements. In addition, a method for reducing two regularization parameters to one is presented. Reducing the amount of regularization parameters simplifies the optimization problem and facilitates a fair comparison between the models with and without a ground magnetometer.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 128
Issue: 5
Article number: e2023JA031394
DOI: 10.1029/2023JA031394
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: This work was funded by the Research Council of Norway (RCN) under Contract 223252/F50. KL and JR were also funded by the RCN under Contract 300844/F50. KL and SH were also funded by the Trond Mohn Foundation.
Dataset Reference: The simulation dataset used in this study is available at Zenodo via (Madelaire, 2023).
Copyright information: © 2023. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.