Comparison Between the CHAMP/STAR Derived Thermospheric Density and the NRLMSISE-00 Model

The derived thermospheric density from the CHAMP/STAR accelerometer observations has been compared with NRLMSISE-00 model, and the major results can be summarized as follows. The thermospheric density is lager in Equinoxes than Solstices, and this is much more notable in high solar level. The ratio between dayside and nightside thermospheric density in low-latitude during the high solar level is about 4 but reduces to 2 in low solar activity, and 3 to 1.5 in middle-latitude. NRLMSISE-00 model can capture the main character of the neutral density, but has lower performance during strong geomagnetic activities. This model overestimates density derived from satellite, and the relative errors are 16.512%, 20.004%, 18.915%, 18.245%, 25.161%, 33.261% and 41.980% from 2002 to 2008. The relative error in high latitude is 27.337%, but low-middle latitude is 24.047%. The model has a better performance under the conditions of middle solar activity level, and the relative error is about 15%.