基于经验模式给定热层温度对热层大气密度反演影响的评估

摘要

Atmospheric drag coefficient CD is a critical parameter in deriving the thermospheric mass density from accelerometer data.Thermospheric temperature from the atmospheric empirical model is usually utilized in the calculation of the CD coefficient.In this paper,we investigate the prior temperature effect on mass density retrieved from the CHAMP accelerometer data during the deep solar minimum year 2008,when the empirical model MSIS00 predicts much higher density.Besides from the MSIS00,the neutral temperatures are estimated from the accelerometer-derived density and subsequently modify neutral composition.Our results show that,the overestimated temperature of the MSIS00 in 2008 introduces the deviation of less than 5％ in the retrieved density from accelerometer data.In addition,the change of atmospheric composition due to temperature can further reduce this effect.%利用加速度计数据反演热层大气密度算法一般需由经验模式给定热层大气温度,进而计算大气阻尼系数CD.本文基于CHAMP卫星加速度计数据反演得到大气密度,以2008年为例,利用反演得到的热层大气密度循环迭代修正大气阻尼系数CD,通过对比修正前后密度偏差,评估经验模式给定热层温度对热层大气密度反演造成的影响.结果表明,经验模式热层温度计算偏差对大气密度反演造成的影响小于5％,而且考虑大气成分的改变则进一步降低了这种影响.