An Improved Ionospheric Conductance Calculation Method

Ionospheric conductance at high latitude plays a critical role in determining the magnetosphere-ionospheric coupling. Accurate estimation of the ionospheric conductance has remained a challenge despite a considerable number of efforts having been devoted to developing various models. One of the methods widely used in magnetosphere models is to estimate ionospheric Pedersen and Hall conductances in relation with auroral electron precipitation (e.g., Robinson et al 1987). However, very few studies have quantified the degree of uncertainties in using such relationships. In this study, four empirical models work in concert to self-consistently calculate Pedersen and Hall conductivity altitude profiles under a variety of precipitation and background conditions, during periods of both low and high geomagnetic and solar activity. Specifically, we apply the Fang et al. (2010) parameterization model to calculate the impact ionization of precipitating electrons with different energies. The background atmospheric, ionospheric, and geomagnetic field conditions are specified using the Naval Research Laboratory Mass Spectrometer Incoherent Scatter radar (NRLMSIS 2.0) model, the International Reference Ionosphere (IRI 2016) model, and the International Geomagnetic Reference Field (IGRF-13) model, respectively. By applying these empirical models, we calculate conductivities resulting from auroral electron precipitation and then obtain conductances. It is found that the Hall conductance decreases with increasing solar and geomagnetic activity, and the Pedersen conductance shows insignificant variability with the activity. An improved conductance empirical model with understandable uncertainty is derived from our results.