太阳活动与热层大气密度的相关性研究

为分析太阳活动对热层大气的影响，使用250km，400km，550km高度处热层大气密度与太阳F_10.7指数数据，研究了二者的周期变化及相关关系. 结果表明，热层大气密度的变化与太阳活动呈现相似的变化趋势；两者均具有显著的27天及11年周期变化特征，热层大气密度还存在7～11天及0.5年和1年的变化特征，且高度越高越明显；热层大气密度对太阳活动的最佳响应滞后为3天，无论何种地磁活动水平下，400km高度处相关性高于250km，550km处相关性最小，且太阳活动下降相期间高于上升相；250km，400km和550km高度处热层大气密度和太阳活动的统计结果分别为饱和、线性和放大关系；高度越高的热层大气密度对太阳活动响应越敏感.

Correlations between solar activity and thermospheric density

The periodic characteristics of solar F_10.7 index and the thermospheric density at 250km, 400km and 550km altitude have been investigated. The results show that the thermospheric density correlates well with the solar activities, and both of them have significant period of 27 days and 11 years. Besides, the thermospheric density also has 7～11 days' period, semiannual and annual variations. The response of thermospheric density lags the solar activity for three days. No matter what the level of geomagnetic activity is, the correlation between solar activity and thermospheric density at 400km is larger than 250km, minimum at 550km. The relationships between the neutral density and solar activity show linear, saturation and amplification features. The thermospheric density in higher altitude is more sensitive to the solar activities.