CHAMP和GRACE-A/B反演大气密度数据评估分析

利用Colorado大学公开发布的2001-2008年CHAMP和GRACE-A/B三颗卫星加速度计反演的400km高度上的大气密度数据，以大气模式NLRMSISE-00为参考，分析反演数据与模式值的误差特点、产生误差的原因、密度的变化及合理性，并通过卫星轨道两行根数（TLE）的反演结果进行验证，主要结论如下.CHAMP密度值整体稍高于GRACE-A/B，CHAMP密度与模式值之间的误差整体小于GRACE-A/B，2007-2008年 GRACE-A/B与模式的相对误差变化起伏较大.2001年CHAMP与模式存在整体偏差，通过相似空间环境条件下的密度变化比对以及利用TLE的反演结果验证，确定2001年的CHAMP反演密度整体偏低.CHAMP及GRACE-A/B密度变化个例显示，卫星密度值会出现一些个性化特征，使用时应根据需求进行分析处理.研究结果可为合理应用该数据提供参考. 

Analysis and Verification of Thermospheric Density Derived from CHAMP and GRACE-A/B Accelerometer Data ormalsize

The data of thermospheric total mass density derived from the high-accuracy accelero-meter on board the CHAMP and GRACE-A/B satellites during 2001-2008 at 400km altitude are analyzed. NRLMSISE-00 is selected as the reference model for comparing with those derived density. Mean Absolute Error (MAE) and Mean Relative Error (MRE) between derived and NLRMSISE-00 model values are given. The characteristics and causes of these errors are analyzed. The density variation and their rationality are also discussed. Moreover, the reliability of the derived density is verified by TLEs density. The main conclusions are as follows. Density obtained by CHAMP is larger than those obtained by GRACE-A/B at 400km altitude. The errors between the density obtained by CHAMP and model value are smaller than those between GRACE-A/B and model. There is a global deviation between the density obtained by CHAMP and model. The density variation in the similar space environment and the density obtained by TLEs show that the density in 2001 obtained by CHAMP is lower than actual values. Examples of the density obtained by CHAMP and GRACE-A/B indicate that there are some individual characteristics of the density obtained by the satellites, and they should be analyzed and chosen in application.