Objective Inferences of the Ionospheric Conductance From a Synthesis of Electromagnetic Observations

The ionospheric conductivity, more specifically conductance, serves as a critical linkage in the electromagnetic energy and momentum couplings between the magnetosphere, ionosphere and thermosphere, dictating important parameters such as ionospheric currents, Joule heating dissipation, and ion-drag. Our ability to adequately address many pressing science questions regarding the couplings hinges on the accurate knowledge of this critical parameter; nonetheless, its global monitoring is almost non-existent. On the other hand, the availability of space-based global observations, such as Iridium magnetometer data, motivates the development of a data assimilation tool with new capabilities to maximize the utility of recent space-based as well as traditional arrays of ground-based observations. This paper presents objective inferences of the conductance from global observations of high-latitude ionospheric electromagnetic variables (e.g., magnetic perturbations, electric fields, high-energy auroral particles) by using an inverse procedure that allows the ionospheric conductance to be an integral part of the optimization.