A statistical analysis of the assimilative mapping of ionospheric electrodynamics auroral specification

Abstract

The assimilative mapping of ionospheric electrodynamics (AMIE) technique utilizes a wide range of electrodynamics measurements to determine high‐latitude maps of the electric potential, electron particle precipitation (average energy and total energy flux), and ionospheric conductance (Hall and Pedersen). AMIE does this by conducting a least squares fit to the difference between the data and a background model. This fit is then added to the background model. This allows for a very stable technique with even minimal amounts of data. The background models are typically statistical models that are driven by the solar wind and interplanetary magnetic field or the hemispheric power index. This study presents results of a statistical validation of the AMIE conductance and particle precipitation calculations and quantifies how using ground magnetometer derived measurements improves upon the result obtained using only a background statistical model. Specifically, we compare AMIE using the Fuller‐Rowell and Evans (1987) model of particle precipitation and ionospheric conductances to DMSP particle precipitation measurements during the period from May to November 1998. The conductances are derived from the particle precipitation using the Robinson et al. (1987) formulation. The Fuller‐Rowell and Evans (1987) results show low (39–21% with increasing AE) energy flux integrals with respect to DMSP auroral passes and differences in mean electron energies. The AMIE runs, in which ground‐based magnetometers were used to modify the particle precipitation using the formulation by Ahn et al. (1983) and Ahn et al. (1998), show significant improvement in correlation to the observational data. We show that it more accurately predicts the particle precipitation than when using only the background model, especially in the 1800–0300 MLT nightside sectors where solar conductance is not significant. In addition, the AMIE results show a clear increase in accuracy with increasing number of magnetometers in a sector.