大气密度模型球谐修正研究

大气模型修正是提高模型精度的一种重要方法.利用CHAMP卫星高精度加速仪反演的密度数据，采用球谐函数的形式对NRLMSISE-00模型进行修正.为了消除轨道高度变化对密度修正结果的影响，将密度数据同化到同一高度处，计算修正之后的密度误差，进而对未来三天的密度进行预报.结果表明，经球谐修正后，修正误差和预报误差均有显著降低.在太阳活动高年，修正误差可降至10%左右，提前1~3天预报精度分别提高31.34%，21.39%和13.75%；太阳低年时修正误差可降至14%左右，提前1~3天预报精度分别提高55.03%，47.79%和43.60%. 

Spherical Calibration Method on Atmospheric Density Model

Making calibration on the atmospheric model density is an important way to improve the accuracy of atmospheric model. By using the atmospheric density data derived from the high-accuracy accelerometer onboard satellite CHAMP, a calibration on NRLMSISE-00 model is developed with the spherical method. Firstly, the atmospheric density is assimilated to the same altitude, then the calibration and prediction error are calculated based on the calibration results. Finally, the atmospheric density of the next 3 days are forcasted. The results show that the calibration and prediction errors are reduced significantly after the spherical calibration. The calibration error is reduced to about 10% during high solar activity year, and the prediction accuracy is improved by 31.34%, 21.39%, 13.75% for the next 3 days respectively. The calibration error is reduced to about 14% during low solar activity year, and the prediction accuracy is improved by 55.03%, 47.79%, 43.60% for the next 3 days respectively.