短周期地磁扰动的时空分布特征研究

Analysis on temporal-spatial distribution of the short-period geomagnetic activities

本文对2008—2010年隆尧地磁台站的地磁水平分量H和磁偏角D的秒数据进行了短时快速傅里叶变换,按连续型地磁脉动Pc2—Pc6所对应的频率范围对频谱进行了频段划分,在此基础上研究了各频段频谱总幅值即短周期地磁扰动的时空分布特征.在时间变化上,同一年中不同频段的幅值具有相似的变化规律,每年的幅变特性与该年对应的Vr指数的时间分布也具有一致的变化形态,仅仅在变化的幅度上存在差异.磁偏角D的幅值和Vr D均呈现出显著的季节变化特征,而水平分量H的幅值和Vr H却不显著.在空间变化上,各频段幅值均随地磁纬度的增加而增大,随地方时变化呈现出双峰双谷的特征.

Based on the SFFT-transform of one-second data of H and D components from Longyao geomagnetic observatory in 2008—2010,the amplitudes of frequency spectrum were obtained.We divided them into 5 parts according to the frequency bands of geomagnetic continuous pulsations（from Pc2 to Pc6）,and then studied their temporal and spatial distribution.For temporal variation,we found that the amplitudes for different frequency bands showed similar changes in the same year and the changes were also similar with Vr index.The D-Pc and VrD showed significant seasonal variation while H-Pc and VrH did not.For spatial variation,the amplitudes increased with the increasing of geomagnetic latitude.Both the amplitudes variation and Vr index showed the same characteristics of two peaks and two valleys.