Conductance Model for Extreme Events : Impact of Auroral Conductance on
Space Weather Forecasts
Abstract
Ionospheric conductance is a crucial factor in accurately estimating the
closure of magnetospheric currents in the ionosphere. Despite its
importance in predictive investigations of the magnetosphere -
ionosphere coupling, the estimation of ionospheric conductance in the
auroral region is precarious in most global first-principles based
models. This impreciseness in estimating this auroral conductance
impedes both our understanding of the magnetosphere-ionosphere system
during extreme space weather events, and predictive capabilities of
ground-based magnetic perturbations during extreme driving which
generate geomagnetically induced currents. In this article, we address
this concern, with the development of an advanced Conductance Model for
Extreme Events (CMEE) that estimates the auroral conductance from field
aligned current values. CMEE has been developed using nonlinear
regression over a year’s worth of one-minute resolution output from
assimilative maps, specifically including times of extreme driving of
the solar wind-magnetosphere-ionosphere system. The model also includes
provisions to enhance the conductance in the aurora using additional
adjustments to refine the auroral oval. CMEE has been incorporated
within the Ridley Ionosphere Model (RIM) of the Space Weather Modeling
Framework (SWMF) for usage in space weather simulations. This paper
compares performance of CMEE against the existing conductance model in
RIM, through a validation process for six space weather events. The
performance analysis indicates overall improvement in the ionospheric
feedback to the magnetosphere. Specifically, the model is able to
improve the prediction of ionospheric currents which impact the
simulated and , resulting in substantial improvements in predictive
skill.