87th AMS Annual Meeting

Tuesday, 16 January 2007: 9:45 AM
Midlatitude Ionospheric Effects of SAPS Electric Fields
210A (Henry B. Gonzalez Convention Center)
Geoff Crowley, Atmospheric & Space Technology Research Associates, San Antonio, TX; and T. Garner, A. D. Richmond, and R. G. Roble
High density ionospheric F-region stormtime plasma enhancements at upper mid-latitudes known as Storm Enhanced Densities (SEDs) are caused by Sub-Auroral Polarization Stream (SAPS) electric fields. In conjunction with SEDs, additional plasma enhancements are observed at low latitudes, but their source and possible connection with SEDs have not been explained. This type of event is a significant feature of space weather, and a major departure from climatology, with potentially important effects on GPS and other systems. It is therefore important to develop the ability to model and forecast such events. This paper describes the results of numerical experiments in which SAPS electric fields from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) algorithm drive the first principles global 3-D Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIMEGCM). Inclusion of the AMIE fields produces significant effects in the modeled ionosphere at middle and sub-auroral latitudes that have not been reproduced by previous versions of the TIMEGCM. A stream of high density plasma appears to be convected from midlatitudes through the throat region near 15 SLT and into the polar cap, while the low latitude electron density is also enhanced by the SAPS fields. We discuss the potential for including such effects in first principles forecast models.

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