Time-scale dependence of solar wind-based regression models of ionospheric electrodynamics

Karl M. Laundal*, Jone P. Reistad, Spencer M. Hatch, Therese Moretto, Anders Ohma, Nikolai Østgaard, Paul A. R. Tenfjord, Christopher C. Finlay, Clemens Kloss

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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The solar wind influence on geospace can be described as the sum of a directly driven component, or dayside reconnection, and an unloading component, associated with the release of magnetic energy via nightside reconnection. The two processes are poorly correlated on short time scales, but exactly equal when averaged over long time windows. Because of this peculiar property, regression models of ionospheric electrodynamics that are based on solar wind data are time scale specific: Models derived from 1 min resolution data will be different from models derived from hourly, daily, or monthly data. We explain and quantify this effect on simple linear regression models of various geomagnetic indices. We also derive a time scale-dependent correction factor that can be used with the Average Magnetic field and Polar current System model. Finally, we show how absolute estimates of the nightside reconnection rate can be calculated from solar wind measurements and geomagnetic indices.
Original languageEnglish
Article number16406
JournalScientific Reports
Issue number1
Number of pages9
Publication statusPublished - 2020


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