The dynamics of the auroral oval and ionospheric trough boundaries according to data from the DMSP satellites and ground-based ionosonde network
Abstract
This paper presents the results of a combined analysis of the experimental data of vertical- and oblique-incidence ionospheric sounding in the north-eastern region of Russia and of the DMSP satellite data for the period 1998-2003. The emphasis is on the diagnostics of the ionospheric trough boundaries and the auroral oval position during geomagnetic disturbances. The auroral oval was monitored using the data from the DMSP satellites posted on the Internet: http://sd-www.jhuapl.edu/Aurora/ovation/ovation_display.html. The structure of the ionospheric trough was determined from the vertical-incidence sounding data for Norilsk (69.4N, 88.1E), Zhigansk (66.8N, 123.4E), Yakutsk (62N, 129.6E), and Magadan (60N, 150.7E), and from the oblique-incidence ionospheric data for the Magadan - Irkutsk (3000 km) and Khabarovsk - Irkutsk (2200 km) paths using ionosondes with a chirp-signal. During geomagnetic disturbances, additional anomalous signals with large amplitude deviations from the great-circle arc were recorded on a regular basis along these paths. Anomalous signals were recorded in the winter and at equinox periods during the night-time of local time, starting from 12 - 14 UT. The time interval of recording anomalous signals was as long as 10 - 11 hours. The appearance of additional signals is caused by side refraction of the bundle of beams at transverse electron density gradients in the region of the ionospheric trough. Coordinated observations at a network of vertical- and oblique-incidence ionosondes made it possible to study the dynamics of the ionospheric trough boundaries at the time of geomagnetic disturbances. On the basis of a combined analysis of the satellite and ground-based data for the periods when the trajectory of satellite flight passes over ionospheric regions of the north-eastern region of Russia, it was possible to establish a correspondence of the auroral oval boundaries and the ionospheric trough position. This permits the spatial position of the auroral oval to be refined, on the basis of a diagnostics of the ionospheric trough using ground-based radio sounding data at periods when satellite measurements are missing.
- Publication:
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35th COSPAR Scientific Assembly
- Pub Date:
- 2004
- Bibcode:
- 2004cosp...35..806K