Effect of Solar Wind Dynamic Pressure Enhancements on Thermosphere Density

We investigate the effect of solar wind dynamic pressure enhancements on thermosphere density variations. We find that the thermospheric density observed by CHAMP and GRACE satellites increases nearly instantaneously after the onset of solar wind dynamic pressure enhancements. This response generally is first observed at high latitudes and can happen at any local time. We compared the effects of dynamic pressure enhancements and the storm-time southward IMF Bz. We found that the thermosphere response to southward IMF Bz is also nearly instantaneous and global, but much stronger than that to dynamic pressure enhancements. However, considering the much higher occurrence rate of dynamic pressure enhancements, the effect of solar wind dynamic pressure enhancements is also distinct in terms of tracking and forecasting satellite potions. We combine observations from the CHAMP and GRACE satellites with those of the Defense Meteorological Satellite Program (DMSP) satellites to explore how energy input via Poynting flux is correlated in time and space with the thermospheric density enhancements and their development.