Comparison of satellite ion drift velocities with AMIE deduced convection patterns

The Assimilative Mapping of Ionospheric Electrodynamics (AMIE) model has been used in a wide range of studies pertaining to the magnetosphere, ionosphere and thermosphere. In these studies historical data from several different data sources (electric fields from radars and satellites, electric currents from satellites, magnetic perturbations from satellites and ground-based magnetometers) have been assimilated. In its real-time mode (rt-AMIE), only data from an array of ground-based magnetometers are assimilated and convection patterns are produced in 1-min increments. However, the reliability of these real-time patterns for applications involving ionosphere-thermosphere specifications and forecasts has never been systematically tested. To address this issue, a comparison of a 1-year dataset of DMSP F13 cross-track ion drift velocities with AMIE convection patterns, based on data from 80 ground-based magnetometers, has been conducted. First, for each high-latitude DMSP velocity observation, the corresponding AMIE value was calculated. Then, the measured and calculated cross-track ion drift velocities along the high-latitude pass were compared and criteria were established to determine whether or not the AMIE patterns adequately fit the measurements. The comparisons were done for a full year (1998) of satellite crossings of the northern polar region (4300 consecutive satellite crossings). The comparisons indicate that the AMIE patterns adequately represented the DMSP observations about 32% of the time, which is a significant improvement over statistical convection patterns (6% of the time). This is particularly impressive in view of the fact that only a limited number of ground-based magnetometers were included in the AMIE patterns used in this study.