2008—2009年电离层对重现型地磁活动的响应

利用2008—2009年的GPS TEC数据，分析了电离层对冕洞引起的重现型地磁活动的响应. 结果表明，在太阳活动低年，电离层TEC表现出与地磁 ap指数（采用全球3h等效幅度指数ap来表征）和太阳风速度相似的9天和13.5天短周期变化，表明TEC的这种短周期特性主要与重现型地磁活动相关. 地磁纬度和地方时分析表明，夜间高纬地区正负相扰动明显，中低纬地区则以正相扰动为主，较大的TEC变幅主要发生在南北半球高纬地区，夜间南半球高纬地区TEC变化相对ap指数变化有相位延迟. 白天中低纬地区正负相扰动明显，TEC短周期变化与ap指数变化相位基本一致. 2008年TEC的9天和13.5天周期变化幅度大于2009年. 

Ionosphere response to recurrent geomagnetic activity during 2008 and 2009

GPS TEC data are used to analyze ionospheric response to recurrent geomagnetic activity in 2008 and 2009. Periodic analysis indicates that the significant periodicities of 9 and 13.5 days exist in in global mean Total Electron Content (TEC), ap index and solar wind speed but not in solar F_10.7 index. This shows that the short period variations in TEC are mainly related to recurrent geomagnetic activity caused by solar high-speed stream. The local time and latitudinal analysis indicates that the positive and negative perturbations always occur at high-latitude of northern and southern hemisphere at nighttime. At middle to low latitudes, there is mainly positive perturbation at night. The amplitude of the nighttime disturbance in high latitude is larger than middle to low latitudes at night. The daytime TEC response at middle to low latitude is generally in-phase with ap's perturbation. There is a time delay between TEC disturbance and ap variations at high-latitude of southern hemisphere. The amplitude of 9-day, 13.5-day periodicities in 2008 are larger than those in 2009.