A D‐Region Ionospheric Imaging Method Using Sferic‐Based Tomography
A D‐Region Ionospheric Imaging Method Using Sferic‐Based Tomography
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DOI：
10.1029/2023ja031573
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发表时间：
2023-08
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影响因子：
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通讯作者：
D. Richardson;J. McCormick;M. Cohen
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作者：
D. Richardson;J. McCormick;M. Cohen
我们提出了一种使用一组空间分布的甚低频 (VLF) 遥感测量来测量 D 区电子密度的断层成像技术。 D 区电离层在许多远程和超视距通信系统中发挥着关键作用；然而，大多数直接测量技术（例如气球和卫星）都无法达到它。幸运的是，D 区域与地球表面结合，形成所谓的地球电离层波导，允许甚低频和低频 (LF) 无线电波传播到全球距离。通过测量这些信号，我们可以估计电子密度的路径测量值，我们假设它是 D 区域的路径平均电子密度分布。在这项工作中，我们使用闪电产生的射电大气 (sferics) 的路径平均推断和层析成像反演来生成美国东南部和墨西哥湾电子密度的 3D 模型。该模型从二维大圆路径观测开始，每个观测都经过参数化，因此包含垂直剖面信息。然后在任意多个高度切片的二维（纬度和经度）上求解断层扫描，以构建 3D 电子密度。我们检查了模型在综合案例中的性能，并确定我们感兴趣的区域内的预期百分比误差优于 10%。我们将我们的模型应用于 2017 年的“美国大日食”，发现不同高度的阳光百分比和电子密度之间存在明显的关系。
We present a tomographic imaging technique for the D‐region electron density using a set of spatially distributed very low frequency (VLF) remote sensing measurements. The D‐region ionosphere plays a critical role in many long‐range and over‐the‐horizon communication systems; however, it is unreachable by most direct measurement techniques such as balloons and satellites. Fortunately, the D region, combined with Earth's surface, forms what is known as the Earth‐Ionosphere waveguide allowing VLF and low frequency (LF) radio waves to propagate to global distances. By measuring these signals, we can estimate a path measurement of the electron density, which we assume to be a path‐averaged electron density profile of the D region. In this work, we use path‐averaged inferences from lightning‐generated radio atmospherics (sferics) with a tomographic inversion to produce 3D models of electron density over the Southeastern United States and the Gulf of Mexico. The model begins with two‐dimensional great circle path observations, each of which is parameterized so it includes vertical profile information. The tomography is then solved in two dimensions (latitude and longitude) at arbitrarily many altitude slices to construct the 3D electron density. We examine the model's performance in the synthetic case and determine that we have an expected percent error better than 10% within our area of interest. We apply our model to the 2017 “Great American Solar Eclipse” and find a clear relationship between sunlight percentage and electron density at different altitudes.