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Ann. Geophys., 24, 107-113, 2006
www.ann-geophys.net/24/107/2006/
© European Geosciences Union 2006
Observing the north polar ionosphere on 30 October 2003 by GPS imaging and IS radars
C. Stolle1, J. Lilensten2, S. Schlüter3, Ch. Jacobi4, M. Rietveld5, and H. Lühr1
1GeoForschungsZentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany
2Laboratoire de Planétologie de Grenoble, BP 53, 38041 Grenoble cedex, France
3DLR, Institute of Communications and Navigation, Kalkhorstweg 53, 17235 Neustrelitz, Germany
4Institute for Meteorology, University of Leipzig, Stephanstr. 3, 04103 Leipzig, Germany
5EISCAT, Ramfjordmoen, 9027 Ramfjordbotn, Norway
Abstract. The evening of 30 October 2003 was subject to a major storm main phase. For
this time, we combine large-scale electron content maps from GPS imaging with
time series of electron density and temperature of two EISCAT radars in
Tromsø and Svalbard and the Sondrestrom radar, for observing the north
polar ionosphere. The GPS assimilations resulted in the image of the electron
content trace of an anti-sunward polar Tongue Of Ionisation (TOI)
consecutively to 20:00 UT. In combination with the radar observations we
concluded that the TOI persisted during the whole period of continuous
southward IMF Bz until about 22:40 UT while its largest extension
toward the nightside auroral region was found between 21:00-22:00 UT. A
typical F region electron temperature of ~2000 K and the plasma
velocity of ~800 ms-1 support its convective origin from
the dayside mid-latitudes. Due to the structured appearance of the electron
content distribution and the radar electron density time series we believe
that discrete plasma patches formed inside the anti-sunward drift pattern.
After two large oscillations of the IMF Bz the nightside plasma
density was observed to re-enhance after 23:00 UT along a longitudinal band
below 70 N. Coinciding electron temperatures of ~2000 K
suggest again the convective nature of the plasma, while a modified
convection pattern is expected.
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