热层大气密度变化特征与太阳辐射和地磁指数的相关性分析

Correlation of Thermosphere Density Variation with Different Solar and Geomagnetic Indices

利用CHAMP卫星加速度仪资料反演的热层大气密度数据,对400km高度上大气密度与五种太阳辐射指数、两种地磁活动指数的变化对应关系进行统计分析,结果表明:(1)密度变化与五种辐射指数的变化一致,相关程度都在0.97以上。若不考虑辐射指数的物理含义,如从数据统计意义上来表征辐射对密度的影响,任何一种辐射指数均能很好地反映密度的变化。(2)密度变化与两种地磁指数ap、Dst都具有较好的相关性。通过对归一化之后的60个磁暴事例进行统计,从上升时间及增加幅度来看,密度的变化与Dst指数相关性更好。(3)建立一个大气密度与Dst之间的一元线性回归关系,并通过CHAMP和GRACE-A两颗卫星比较验证,说明Dst指数可较好地反映大气密度整体态势的变化。

Based on thermosphere density data of the CHAMP satellite, relationships between the atmospheric density and five solar radiation indices and two geomagnetic indices are analyzed. Results show that： （a） Correlation coefficient between density and each of the five solar indices is greater than 0.97.（b） Compared with ap, Dst index is better correlated with density through analyzing 60 geomagnetic storm samples. （c） A linear regression equation is founded, and the result of comparison between CHAMP and GRACE-A observed data shows that Dst can better reflect the variation of thermosphere density.