中文摘要：

利用北半球IGS观测站提供的150个GPS观测资料,结合三维电离层层析方法,反演了平静日下北半球上空电离层电子密度的变化特征。结果表明：整个研究区域电子密度在不同纬度和不同高度上存在明显的日变特征,在0°经度剖面上,电子密度最大值出现在世界时13～15时,随着时间推移,峰值幅度衰减;在北纬20°附近,世界时11～13时电子密度出现双峰值;北纬50°～80°范围,电子密度无大的起伏;反演结果说明了电离层三维层析技术为监测电离层时空结构提供了一种强有力的实验支持。

英文摘要：

Based on 150 GPS data from IGS observation station in Northern Hemisphere,combined with three-dimensional computerized ionospheric tomography technique,the temporal-spatial variations of ionospheric electron density during magnetic quiet in northern hemisphere were inverted.Reconstructed images showed the diurnal evolution of equatorial anomaly and the variations of the vertical structure of ionosphere.The maximum value of electron density occurred at UT13~15 o′clock in 0° longitude zones.The peak amplitude of electron density reduced gradually.At 20°N,double peak values occurred at UT11~13 o′clock,and there was no large undulation at 50°～80°.It is demonstrated that time-dependent 3D CIT with ground-based was effective for monitoring the evolution of large-scale ionospheric structures.