Abstract This paper presents a case study when due to the descending additional U-shaped trace on vertical incidence ionograms, increased critical frequency stabilizes. This corresponds to an ionospheric disturbance that moves toward the ionosonde and then stays overhead. Within a 2D model, traveling ionospheric disturbances (TIDs) are superimposed on the inverted background ionosphere. So ray tracing is used to obtain propagation paths through non-stratified ionosphere thus synthesizing the disturbed ionogram traces. Investigated are changes in the cusp shape caused by varying TID parameters. A cusp-fitting method to determine the TID amplitude, spatial scale, and horizontal drift velocity are shown.

中文翻译：

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使用垂直入射电离图上的 U 形迹线研究移动电离层扰动的特征

摘要 本文介绍了一个案例研究，当垂直入射电离图上的附加 U 形轨迹下降时，增加的临界频率趋于稳定。这对应于向电离探空仪移动然后停留在头顶的电离层扰动。在二维模型中，行进电离层扰动 (TID) 叠加在反向背景电离层上。因此，射线追踪用于获得穿过非分层电离层的传播路径，从而合成受干扰的电离图迹线。研究的是由变化的 TID 参数引起的尖端形状的变化。显示了确定 TID 幅度、空间尺度和水平漂移速度的尖点拟合方法。