We determine the strength and location of the ionospheric currents responsible for the polar electrojets from magnetic data collected by the Swarm satellite constellation on an orbit-by-orbit basis. The ionospheric currents are modelled using a simple, yet robust, method by a series of line currents at 110 km altitude (corresponding to the ionospheric E-layer) perpendicular to the satellite orbit, separated by 1 • (about 113 km). We assess the reliability of our method, with the aim of a possible near-real-time application. A study of the effect of different regularization methods is therefore carried out. An L 1 model regularization of the second-order spatial differences, and robust treatment of the data (to account for non-Gaussian error distributions), yields the most encouraging results. We apply our approach to two three-weekly data periods in March 2014 (geomagnetic quiet conditions) and March 2015 (more disturbed conditions), respectively. Our orbit-by-orbit approach also allows the temporal evolution of the polar electrojets to be investigated. We find remarkable agreement of the ionospheric activity in Northern and Southern polar regions, with correlation exceeding 0.9 for periods longer than two days. Reliability of the approach is shown by three key results: (1) a common regularization parameter for all orbits with enough data coverage, (2) 0.95 squared coherence with the Auroral Electrojet index, and (3) 0.97 squared coherence is found between the side-by-side flying satellites, Alpha and Charlie, indicating a method invariant to small changes in data input. All these results indicate a possible automated near-real-time application.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.