Summary

The Weimer and IZMEM statistical convection models are driven with a time series of interplanetary magnetic field (IMF) measurements made onboard the Wind spacecraft. The model outputs are used to infer convection velocity at Casey, Antarctica (80.8°S geomagnetic latitude), and then compared with measurements of Doppler velocity made using a Digisonde, and measurements of F-region convection implied by a collocated magnetometer. During a single, representative campaign interval, Feb. 13-17, the Weimer model explained 19% (42%) of the variation in Doppler speed (direction) observed by the Digisonde, and 21% (14%) of the equivalent convection components observed by the magnetometer. This compares with IZMEM which explained 16% (46%) of the variation in Doppler speed (direction) observed by the Digisonde, and 34% (32%) of the equivalent convection components observed by the magnetometer. In general, there was better agreement between convection direction than convection speed. Some of the disagreement was probably due to differences between the IMF measured by Wind located ~170 RE upstream in the solar wind and the IMF actually arriving at the magnetopause. However, the results of this study do show that measurements of ionospheric velocity using different experimental techniques need heavy averaging to identify a common component of velocity controlled by the IMF vector. The present time series approach was also used to estimate 16 ± 5 minutes for the time it takes the ionospheric convection to reconfigure in response to IMF changes occurring at the magnetopause.

Authors:Parkinson M.L. Smith P.R. Dyson P.L. Morris R.J. Publisher: Elsevier Published in: 1999 Category 1: Peer-reviewed literature Program area: Space and Atmospheric Sciences
Parkinson M.L., Smith P.R., Dyson P.L., Morris R.J. (1999) Nowcasting convection velocity in the high-latitude ionosphere using statistical models, Journal of Atmospheric and Solar-Terrestrial Physics 61 (11). 841-855;

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