Latitudinal Impacts of Joule Heating on the High- Latitude Thermospheric Density Enhancement During Geomagnetic Storms

摘要

We investigate the thermosphere latitudinal response to Joule heating from 265 geomagnetic storms during the period of January 2002 to December 2008. The total mass density enhancements at 400 km are derived from the Challenging Minisatellite Payload (CHAMP) and the Gravity R_(eco)very and Climate Experiment (GRACE) satellites with temporal and spatial coverage. We examine Joule heating and its influence on the thermospheric density using data from the Defense Meteorological Satellite Program (DMSP) spacecraft and Weimer-2001 electric potential model for storms. The results show that during geomagnetic storms, Joule heating can cause the thermospheric density to enhance in the higher-latitude areas. In addition, during weak and moderate geomagnetic storms, the difference in the latitude corresponding to strong Joule heating with the latitude where high-latitude thermospheric density enhances is only 0°-10° latitudes, while increases to 10°-15° for the intense storms. Besides, it is found that the peak density enhancement in LT is closer to peak Joule heating for more intense geomagnetic storms.