Virtual Height Characteristics of Ionospheric and Ground Scatter Observed by Mid‐Latitude SuperDARN HF Radars
Virtual Height Characteristics of Ionospheric and Ground Scatter Observed by Mid‐Latitude SuperDARN HF Radars
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DOI：
10.1029/2022rs007429
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发表时间：
2022-01
期刊：
影响因子：
1.6
通讯作者：
E. Thomas;S. Shepherd
中科院分区：
文献类型：
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作者：
E. Thomas;S. Shepherd
高频（HF）无线电信号的传播强烈依赖于沿着通信链路的电离层电子密度结构。超级双极光雷达网络（SuperDARN）的地基高频空间天气雷达利用传输信号的电离层折射来监测E和F区域等离子体不规则性的全球环流。以前的研究已经评估了地球电离层极光区和极区电离层不规则结构的后向散射回波的传播特性。默认情况下，这些回波的地理位置是通过经验模型来确定的，这些经验模型根据雷达信号路径上沿着的测量距离来估计虚拟后向散射高度。然而，这些虚拟高度模型的性能尚未在中纬度SuperDARN雷达观测或地面散射（GS）传播模式下进行评估。在这项研究中，我们使用来自圣诞谷东部和西部雷达的5年数据推导出一个适用于中纬度SuperDARN观测的虚拟高度模型。该经验模型可应用于电离层和GS观测，并与现有的高纬度虚拟高度模型相比，提供了对后向散射位置的地面范围的改进估计。我们还确定了重叠的半跳F区域电离层散射和一跳E区域GS的区域，其中测量的雷达参数（例如，速度、谱宽、仰角）不足以区分两种散射类型。需要进一步的研究来确定这些起源模糊的后向散射回波是否被其他中纬度SuperDARN雷达观测到，以及它们对散射分类方案的潜在影响。
Propagation of high‐frequency (HF) radio signals is strongly dependent on the ionospheric electron density structure along a communications link. The ground‐based, HF space weather radars of the Super Dual Auroral Radar Network (SuperDARN) utilize the ionospheric refraction of transmitted signals to monitor the global circulation of E‐ and F‐region plasma irregularities. Previous studies have assessed the propagation characteristics of backscatter echoes from ionospheric irregularities in the auroral and polar regions of the Earth's ionosphere. By default, the geographic location of these echoes are found using empirical models which estimate the virtual backscattering height from the measured range along the radar signal path. However, the performance of these virtual height models has not yet been evaluated for mid‐latitude SuperDARN radar observations or for ground scatter (GS) propagation modes. In this study, we derive a virtual height model suitable for mid‐latitude SuperDARN observations using 5 years of data from the Christmas Valley East and West radars. This empirical model can be applied to both ionospheric and GS observations and provides an improved estimate of the ground range to the backscatter location compared to existing high‐latitude virtual height models. We also identify a region of overlapping half‐hop F‐region ionospheric scatter and one‐hop E‐region GS where the measured radar parameters (e.g., velocity, spectral width, elevation angle) are insufficient to discriminate between the two scatter types. Further studies are required to determine whether these backscatter echoes of ambiguous origin are observed by other mid‐latitude SuperDARN radars and their potential impact on scatter classification schemes.