The effect of ionospheric conductance on reconnection estimates based on ionospheric observations

Ground magnetometer measurements are frequently used to study ionospheric electrodynamics. It is possible to relate and combine ground magnetometer measurements with ionospheric convection measurements through the  ionospheric Ohm’s law. It is therefore important to have knowledge of the auroral conductances in order to utilize both these sources of information together when describing the 2D ionospheric electrodynamics. However, auroral conductances are very difficult to evaluate. In this study we use a new data assimilation technique on an event study to investigate the effect of different methods to retrieve auroral conductances. We focus on the effect on estimates of nightside reconnection, based on ionospheric convection and optical observations of the open closed boundary. We show that different choices of conductance lead to differences in ionospheric convection velocities, and hence differences in estimates of the reconnection electric fields.