不同强度磁暴期间热层大气密度响应特征分析

利用CHAMP卫星数据，对2002-2008年12个不同强度磁暴事件期间的热层大气密度变化特征进行分析，并研究对应磁暴期间大气模式NRLMSISE-00分布特征.结果表明，大磁暴期间日侧大气密度峰值从高纬到低纬的时间延迟为2h，中小磁暴期间的延迟时间为3～4h；春秋季暴时大气密度分布基本呈南北对称分布，而夏冬季大气密度的分布是夏半球大于冬半球，春秋季暴时大气密度大于夏冬季；NRLMSISE-00大气模式得到的热层大气密度很好的体现了半球分布以及季节分布的特征，但模式模拟结果偏小；Dst指数峰值比ap指数峰值更能反应大气密度的变化情况. 

Characteristics Analysis of Thermospheric Density Response during the Different Intensity of Geomagnetic Storms

The CHAMP satellite data is used to analyze the characteristics of the thermospheric density during 12 different intensity geomagnetic storm events from 2002 to 2008,and the distribution characteristics of NRLMSISE-00 model during the corresponding magnetic storm events are studied.The results show that during large geomagnetic storms,the time delay of the peak thermospheric density from high latitude to low latitude is 2 hours,while the time delay during medium and small geomagnetic storms is about 3 to 4 hours.The distribution of thermospheric density in spring and autumn is basically symmetric between north and south,while in summer and winter the thermospheric density of summer hemisphere is greater than that in winter hemisphere.The thermospheric density in spring and autumn is greater than that in summer and winter.The thermospheric density obtained by the NRLMSISE-00 simulates well the pattern of the hemispherical distribution and seasonal distribution characteristics,but the simulation is smaller than the measurements.The peak change of Dst index can reflect the change of atmospheric density better than the peak change of ap index.