Assimilative Mapping of Ionospheric Electrodynamics (AMIE) Procedure
The Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure is an algorithm designed to quantify high-latitude electric field, electric current and conductance patterns. For any given time the procedure incorporates data from both-ground and space-based instruments as well as a-priori information about features of the electrodynamics. Patterns are derived from an optimally constrained, weighted least-squares fit of coefficients to data. The mappings usually have a heavy reliance on ground magnetometer data, ion drift meter data from the DMSP satellites and drifts estimated from ground-based coherent and incoherent scatter radars.
Ohm's Law applied to the ionosphere allows ground magnetometer data to be related to the mapped electric field through the Pedersen and Hall conductivies. However, a reliable conductivity distribution is required for inverting the information about ionospheric currents into information about ionospheric electric fields. The AMIE procedure first estimates a conductivity distribution before fitting the electric fields. The ion drifts sensed by the instruments aboard the DMSP spacecraft provide a more direct (and therefore more heavily weighted) estimate of the ionospheric electric field magnitude and direction.
Details of the fitting procedure can be found in:
Richmond, A. D., and Y. Kamide, Mapping electrodynamic features of
the high-latitude ionosphere from localized observations:
Technique, J. Geophys. Res., 93, 5741, 1988.
Richmond, A. D., Assimilative Mapping of Ionospheric
Electrodynamics, Adv. Space Res., 6, (6)59, 1992.
A recent application of the AMIE procedure is described in:
Knipp, D. J. , et al., Ionospheric convection response to slow, strong variations in a northward interplanetary magnetic field: A case study for January 14, 1988, J. Geophys. Res., 98, 19273-19292, 1993.
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