| Summary: | Solar-Terrestrial and Space Physics (STSP) Paper No.: 45. This study investigates the evolution of Jan 10 1997 magnetic storm and the night-time TEC climate change created by the impact of interplanetary shock wave and associated events on the ionosphere. Its main aims are to learn about the response of night-time ionosphere to these interplanetary events particularly focusing on the reaction of night-time Weddell Sea Anomaly. To monitor the process of storm evolution, the WIND, DMSP and NOAA satellite data are utilized. To track down the consequential ionospheric changes, the NASA radar data are employed. As results indicate, the first significant response of night-time Weddell Sea Anomaly was its 25% TEC increase from its quiet-time behavior after the first major storm event when the enhanced westward electric field penetrated to the ionosphere before the shielding process took place. At around 8UT, the second major electric field penetration triggered the depletion of equatorial and mid-latitude ionosphere and launched TIDs. Following a period of very bright aurora (~12UT), southern mid-latitude electron density enhancements reached their maximum. Their noticeable features, confirmed by DMSP observations, are the sudden TEC drop off that is the signature of plasmapause, and the ionization sub-peak that is the signature of discrete aurora. During the recovery phase, the Weddell Sea Anomaly became significantly (45%) depleted. This study concludes that the thermospheric winds and changes in the neutral atmospheric composition produced by Joule heating and electric fields are the major geophysical factors changing the night-time space weather during the studied period.
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