Emulating and calibrating the multiple-fidelity Lyon-Fedder-Mobarry magnetosphere-ionosphere coupled computer model

Abstract

The Lyon-Fedder-Mobarry global magnetosphere-ionosphere coupled model LFM-MIX is used to study Sun-Earth interactions by simulating geomagnetic storms. This work focuses on relating the multifidelity output from LFM-MIX to field observations of ionospheric conductance. Given a set of input values and solar wind data, LFM-MIX numerically solves the magnetohydrodynamic equations and outputs a bivariate spatiotemporal field of ionospheric energy and flux. Of particular interest here are LFM-MIX input settings required to match corresponding output with field observations. To estimate these input settings, a multivariate spatiotemporal statistical LFM-MIX emulator is constructed. The statistical emulator leverages the multiple fidelities such that the less computationally demanding yet lower fidelity LFM-MIX is used to provide estimates of the higher fidelity output. The higher fidelity LFM-MIX output is then used for calibration by using additive and non-linear discrepancy functions.